View Full Version : 340 heads on a 350



randyrhr
10-12-2009, 08:47 PM
I know this one has been batted around somewhat but wanted to relate a motor combination I just got in a project car . This had a '75 350 block with '66 340 heads, intake and exhaust bolted on. I never did try to run it - didn't care as a 455 is going in. Looked like it had actually been running. I'm thinking that if the 340 cam were installed it might run. I haven't tried to compare all the detail dimensions to see if it would work. The lifters looked like they lined up well on the cam lobes (all were just slightly off center) and none of the push rods looked "non-parallel" so I think the lobe/valve spacing was probably the same or very close.

Anybody had any experience with a combination like this or any thoughts about it. Just curious - not interested in trying to run it.

Randyrhr
67 GS 4spd convert project underway

bob k. mando
10-13-2009, 08:21 PM
I'm thinking that if the 340 cam were installed it might run.

yes, it would certainly require a 340 cam. there doesn't appear to be any issue with the center pushrods interfering anywhere?

word has been that on a 340, the center pushrods are spaced further apart in order to get around the siamesed intake runners.

the 340 cam would also require adapter bearings. on the 215/300/340/Rover, the journals get smaller as you move to the back of the block. on the 350, they are all the same size.




Anybody had any experience with a combination like this or any thoughts about it.

we have been bandying this idea around quite a bit in the Buick community, especially since TA announced they were going to produce "Rover style" aluminum heads.


not interested in trying to run it.

dang, i know there are quite a few people who would like to see you do it though.

randyrhr
10-18-2009, 11:18 PM
Sorry about the long delay - had a Class Reunion to attend - and a great time was had by all!

Anyway - to answer your question about the push rod alignment - I only checked it visually before pulling the heads but they all looked really, really, "right" .

Now you have me thinking about putting the heads and manifold back on and trying to at least start it - just have to find the time! BTW it had the correct orig '66 carburetor on it.

I'll do a little actual measuring and post the results sometime after the first of Nov (another short trip out of town getting in the way).

bob k. mando
10-19-2009, 11:19 AM
any information that you can give us on this hybrid will be greatly appreciated.

if you'd rather not, it might be possible to locate a Buick fan in the NW who'd be interested in playing with it.

randyrhr
10-19-2009, 04:31 PM
Just in case I've misread something - here are the numbers I took off the parts as I disassembled it - maybe you could double check my info:

350 Short block - casting no. 1241748 - 1975. There is an extremely small ridge and the bore is standard (3.80"). Virtually no rust or scoring and no visible cracks in the cylinder walls. The motor looks pretty good overall but it's been sitting for about 25 years.

340 Intake Manifold - casting no. 1374559 - 1966 4bbl

340 Heads - casting no. 1376330 - 1966 these look pretty good, they were bolted onto the 350 block.

340 Exhaust Manifolds - casting no. 1375901 - L, casting no. 1375912 - R.

bob k. mando
10-19-2009, 05:27 PM
the 340 heads/intake/exhaust are easy to identify.

the 340 siameses the center intake passages while all of the exhaust ports have discrete runners. the stock 215/300/340/Rover exh manifold looks almost like a set of cast shorty headers.

the 350 has siamesed center exhaust runners and looks quite a bit like a big block Buick manifold.


There is an extremely small ridge and the bore is standard (3.80"). Virtually no rust or scoring and no visible cracks in the cylinder walls.

it appears that you have the engine in some stage of disassembly. if it has a stock type 340 cam in it, the cam bearings will have to be non-standard adapter bearings. all of the 350 bearing journals are the same diameter. the 340 was designed with journals that get smaller in size the further towards the back of the block you get. so, bearing thickness on the rear journal will have to humongous in relation to bearing thickness on the front journal if you have a 340 cam in a 350 block.

if they somehow custom ground ground a 350 cam to a 340 pattern, all of the bearings will be standard 350 bearings, ie - the same specification for diameter and material thickness.

randyrhr
10-19-2009, 07:05 PM
Yes, I have the heads off but have not pulled the front cover (or cam of course). And from the heads up this is obviously 340 hardware.

I just went out and set one head back on with push rods in place. Measuring with a dial caliper and my eyeball here are some numbers for the center pair (340-intakes)

The top of the push rods, fore and aft spacing, at the rockers - 2.720
The lifters - fore and aft spacing - 2.550

Each of the actual intake/exhaust pairs are slightly wider at the rocker arms than at the lifters.

The head gasket push rod holes line up perfectly with the lifters and not with the rockers. The gasket pattern on the block looks like it fit the block just right around the cylinders and based on these two observations I believe they used a 350 head gasket (And it looks like it fit just right on the underside of the 340 head too) . Note too that the head alignment dowel pins are a perfect fit.

Now that I'm really looking closely, the push rods are definitely visually skewed a little but none of them touch any of the clearance holes through the head or the clearance holes in the gasket (which are actually spaced correctly for the lifters and not the rockers). The ends of the push rods, the rocker "sockets" and the lifter "sockets" don't show any abnormal visual wear patterns (I actually only cleaned up and looked at the center two so far).

The center two are skewed the most and each intake/exhaust pair is also skewed a little (spread out at the top as noted above). Interestingly, the third rocker in from each end looks to be lined up just about perfectly with it's corresponding lifter. All the others get a little further off as you move either toward the center pair or toward the front or rear of the block.

When I get a little more time I'm going to pull that cam and see what the bearings/journals look like - that will have to wait several days. I'll keep you posted.

Do you know of a reference that would have some useful dimensional info - like cylinder spacing, valve spacing, cam lobe center-to-center distance, etc that might help here. Bore and stroke and the bearing sizes are easy but some of the other stuff I haven't found yet.

Also - if you think of anything else I might look at or measure, let me know. I'm way too interested now so I'm going to get some gaskets and put this thing together enough to try starting it one of these days soon.

bob k. mando
10-20-2009, 09:11 AM
cylinder bore spacing on the SBB's is 4.240"

i'm going to try to get ahold of somebody else i know and refer them too this thread.

bob k. mando
10-20-2009, 09:20 AM
engine section of 340 in 1966 Chassis Manual:
http://www.teambuick.com/reference/library/66_chassis/60-b.pdf


engine section of 350 in 1971 Chassis Manual:
http://www.teambuick.com/reference/library/71_chassis/files/60-b.pdf

Dr. Frankenbuick
10-20-2009, 04:21 PM
You guys are aware the intake and exhaust valves are reversed between a 340 and 350 right (the middle two cylinders to be more precice)?

Jim Blackwood
10-20-2009, 05:49 PM
Randy, this is a real find!

We've been kicking around the idea for several years now but so far you are the first with the parts actually assembled. If it did run, I'd guess it has a custom ground cam in it. If you can see the rear cam bearing, an oversize bearing to allow use of the 340 cam should be fairly obvious as it should be around 1/8" thick. But based on information from direct measurements, the center cam lobes should then be off enough to cause trouble. If you have it together enough to do it, rotate the crank and see if the valves open in the correct sequence. You are particularly looking to see if the center four valves are reversed. Check out this link, particularly page 4:
http://www.v8buick.com/showthread.php?t=156953&highlight=340+heads+350+block

From your observations it could be that pushrod misalignment is less of an issue than we've been led to believe based on measurements taken, and this would be a tremendous benefit. So it is crucial to this effort to find out just how well the parts fit together. If you could post some photos that would be most helpful. If it turns out that the pushrod geometry really is that close, then all that would be needed to run the new TA heads on a 350 block is a custom cam. Not at all an insurmountable obstacle.

Jim

Jim Blackwood
10-21-2009, 07:13 AM
Also, if you get the chance, I'm guessing from your comments that the engine has a custom ground cam in it. That is based on your description of the lobes being well centered in the lifter bores. If that is the case and the valve sequencing is correct then it would be of tremendous benefit to learn the source of this cam. There may be some markings on the nose of the cam that can be used to help identify it. That is actually the last remaining piece of the puzzle that needs to be resolved, and if known might enable the building of high performance 350's in the neighborhood of 400 lbs of weight. Obviously this has potential.

Jim

turbos1w
10-23-2009, 10:59 PM
Hey guys, I'm interested in a couple things your talking about but 1st, why we want to do this swap? Whats the real benefit? Are the runners bigger, smaller, do they have a smaller cc or larger cc combustion chamber? Inquiering minds want to know.

bob k. mando
10-24-2009, 07:39 AM
why we want to do this swap? Whats the real benefit?

the single largest benefit is actually slightly in the future. www.TAPerformance.com has 215/300/340/Rover aluminum heads in prototype at a casting plant. they're hoping to be in production by next year.

if we can use this style of heads this would be the very first aluminum head to ever be available for a Buick 350.

other benefits would be:
availability of existing Rover style parts to use ( headers, intakes, valve covers, etc )
modern combustion chamber design
much better than factory runners, straight out of the box ( TA big block heads normally flow as good or better than heavily ported factory irons )
big weight savings over the factory head+intake combo



Are the runners bigger, smaller, do they have a smaller cc or larger cc combustion chamber?

i think as far as the factory iron castings go, there's probably only one advantage to a 340 head.

a Rover style head separates all of the exhaust ports so you don't have a hot spot in the center of the head like you do with a SBB 350 or BBB. this doesn't mean much for street use but it makes a difference for all out race applications.

Buick/Rover engines other than the 340 don't have the runner size to support a 350 displacement.

Jim Blackwood
10-24-2009, 10:28 AM
why we want to do this swap? Whats the real benefit?

Buick/Rover engines other than the 340 don't have the runner size to support a 350 displacement.

Unless you add a blower. :bana:

The weight reduction is a big deal too, getting the weight of the engine down to around 400lbs or less for 350 cu.in. with an iron block makes a big difference in many applications. Also cheap aluminum valve covers are available. Those things may not mean much for restoration type applications, but for others it can make or break the build.

Jim

turbos1w
10-24-2009, 05:24 PM
So let me get this straight, The Rover is a 340 or it just uses the 340 base line parts? So tell me this, I have a 66 Skylark w/340 4bbl, are there parts from a rover that will work?

Jim Blackwood
10-24-2009, 05:38 PM
Aw heck no, the Rover was a 215. It's grown up to about 4.6 liters but that's still smaller than a 300. It *is* aluminum which is pretty cool, and fits in a lot of cars, but stepping up to a 300 or 340 with aluminum heads and intake is very much worth the roughly 80 lb weight penalty.

What Rover parts fit your 340? Well, valve covers for one, there's a front cover with a concentric oil pump that might be made to work, cams, rocker shafts, the P76 intake with about 1/4" spacers but you might not like the runners, Wildcat heads$$$, the new TA heads, and ancillaries. Not a great source for spare parts but one to keep in mind.

Jim

bob k. mando
10-24-2009, 07:12 PM
So let me get this straight, The Rover is a 340 or it just uses the 340 base line parts?

no, as Jim says, a Rover v8 is not a 340. is what it is, is in the Small Block Buick family. the original SBB v8 was the aluminum 215ci, in production from 1961-63. in 64, GM transitioned to the cast iron, taller deck 300ci and sold the designs and molds for the aluminum engine to British Leyland/Land Rover in 1965. BL / Land Rover referred to it by it's metric displacement of 3.5L

so the 215 ( short deck ), 300 ( mid deck ), 340 ( tall deck ) and Rover engines ( short to mid deck ) can all swap many parts.

the Buick 350 is still in the SBB v8 family, but when they introduced it in 1968 they changed the valve order around so that the center exhaust runners on each side were siamesed together just like a SBC. makes for cheaper casting and assembly on the exh manifolds. if you look at your heads, you'll see four discrete exhaust runners on each side. a 350 only has "three" runners.

in order to keep from people getting confused and installing the wrong parts, Buick made several other changes like making all of the cam bearings the same diameter ( so it's impossible to install an earlier cam in a 350 or vice versa ) and changing the valve cover design.

your 340 has the same crankshaft as the 350, it just has a slightly smaller bore. there's no real advantage to you in "upgrading" to a Buick 350 block as you'd only gain 2.94% displacement.




the P76 intake

just so you know, the "P76" is an Australian only variation of the Rover design that displaces 4.4L but it had a taller deck and longer rods than any other Rover variant.
http://en.wikipedia.org/wiki/Rover_V8#4.4



It's grown up to about 4.6 liters but that's still smaller than a 300.

actually, TVR punched it out to 5.0L in the Griffith 500 and Chimaera. at 305ci, it's slightly larger than a 300. still a shorter deck than the 300, 340, 350 and P76 though.
http://www.carfolio.com/specifications/models/car/?car=30481



Unless you add a blower.

tch, tch, tch, Jim.

you know that most people on the 350 end of this are not dealing with your type of under weight, over powered, traction limited cars. runner size and intake charge heating will be a concern for most of us here in the States. :D

Jim Blackwood
10-25-2009, 08:38 AM
runner size and intake charge heating will be a concern for most of us here in the States. :D

Hmmm.... building an experimental intercooler for that.
My target is 300hp, a fairly modest goal for a 340 I think.;) That'll give me 1 hp per 8 lbs of vehicle weight which should be plenty.

Jim

turbos1w
10-25-2009, 09:57 AM
Turbo's are simple enough, 300hp should be a walk in the park on motor alone. Are these motors that weak? If your stock 340 only makes 150hp on motor you can ad 14psi and basicly double you numbers.

bob k. mando
10-25-2009, 01:00 PM
Are these motors that weak?

umm, i believe the original aluminum motor is the only GM design to hold two F1 championships. 1966-67, will be listed as a REPCO motor but is actually an OHC modification taken from Rover.
http://www.britishv8.org/Articles/Rover-Autocar-Article.htm

it's also the basis of the v6 that NASCAR was using in the Busch series back in the 80s and early 90s.
http://www.teambuick.com/reference/library/v6_stage2.php

as far as i know, the 'best' 350 to ever go on a dyno was an engine that was designed for a turbo that pushed close to 700hp normally aspirated. it went over 1000 on boost. Jim Burek at PAE had one NA over 550. keep in mind, there are no performance parts to speak of for these engines and there are no 4 bolt main blocks.

that's one of the reasons why we're interested in moving to a "Rover style" head. there HAS been hot rod and performance development on the Rover engines ... in the UK and Australia.

the 'problem' with Buick engines is that they came in near top of the line ( GM has always marketed Buick just below Cadillac ) cars. this means a lack of production numbers in relation to Chevy and a lack of hot rodding opportunities by the shade tree mechanics who tend to drive performance development. shade tree mechanics tend not to have the money to invest in an expensive car.

i think there's a reason why Jim has that "wink" smiley in that post.

Jim Blackwood
10-25-2009, 01:38 PM
OK, I'll fess up. So often you hear extravagant horsepower claims, often with nothing to back them up and I don't want to be seen that way. I've gotten my fair share of incredulous looks, usually when talking about something I've built without whatever it is being present and it isn't all that comfortable even though I'm telling the absolute straight truth. So I figure the best thing to do is to make what has to be seen as a reasonable claim. I'll probably never put the car on the dyno anyway, and all I really care about is the way it drives. So what if it's more than claimed? At least that way I won't get called on to prove it. And at 300hp, an MGB takes an experienced hand to drive safely.

300 is just a few ponies more than stock so that isn't much of a stretch. I should be able to do that easy. The motor has some custom parts, it's got (iirc) a 2.4 overdrive on an M-112 Eaton and the aforementioned intercooler. I think 300 will be a walk in the park even with the '64 300 heads. What'y you guys think?

Jim

sean buick 76
10-31-2009, 10:31 PM
You are pretty funny Jim, and you will be over 500 hp :shifter:

This is all very interesting, I would like to hear more about this engine and especially hear that he gets it running! I just find it hard to believe that someone went to this much trouble to build a 350 with 340 top end to only gain 10 cubes. I have a feeling that the cam is still a 350 cam and the person tossed it together because it was what he had.

There is no way that the 340 heads out perform the 350 heads but maybe I am wrong! Anyone have flow numbers for stock 340 heads? I have numbers here for a stock 350 head to compare.

If all this is true then maybe I need to look into my 215 alum heads and how much I can get them to flow? Most likely the 64 alum 340 heads would be the best bet although rare.... Another option is the iron 340 heads which may have more room for head porting and I believe they flow better than the alum 340 heads anyway.

bob k. mando
10-31-2009, 10:50 PM
I believe they flow better than the alum 340 heads anyway.

there are no "aluminum 340 heads". never have been. while there aren't any important differences between a "300 head" and a "340 head", a 340 never had anything but cast iron on top.



I just find it hard to believe that someone went to this much trouble to build a 350 with 340 top end to only gain 10 cubes.

if he overheated the 350 and warped the heads and he had a 340 sitting there, swapping heads+manifolds+cam would only require adapter bearings to get going. shouldn't have been that expensive if he was doing his own assembly.

that is a good point though. if it should turn out that this transplant works, a lot of 1961-67 people could get a really cheap bore/stroke job by swapping a 350 short block into their car. and that's something i'm sure the 215 and 300 guys would love.




Anyone have flow numbers for stock 340 heads?

it's not the stock heads that concern me.

the 340 intake was of interest because you might could use it to kludge a Rover racing aluminum head onto a 350. now the TA head will be coming on line as well.




I have a feeling that the cam is still a 350 cam and the person tossed it together because it was what he had.

that's a possibility. which wouldn't disprove the viability of the project but it would certainly render this mule difficult to run. i think it would only fire on 4 cylinders? very rough, if it runs at all.

340=EI,EI,IE,IE vs
350=EI,IE,EI,IE



speaking of which:
Randy, the motor, wtf? any updates? :bana:

Jim Blackwood
11-01-2009, 06:21 AM
EI, EI, Oh!

Sean, Randy stated that the lobes were centered under the lifter bores, which means he either has a stock 350 cam in there (massive built-in positive flow EGR... how that could possibly run I don't know) or a custom cam. My guess, if it ever ran it only idled... very poorly. Of course if he left out the center lifters and pushrods it'd run just fine, as a 4 cylinder.

Why do it? Well we've been trying to get someone to try it for two years now. I just wish Randy would come back on line and let us know his progress. Maybe he made a mistake and they really are 350 heads, or it really is a 340 block?

Bob, I hope those nasty rumors about the TA head prices aren't true.

Jim

sean buick 76
11-02-2009, 08:23 PM
I believe they flow better than the alum 340 heads anyway.

there are no "aluminum 340 heads". never have been. while there aren't any important differences between a "300 head" and a "340 head", a 340 never had anything but cast iron on top.



Anyone have flow numbers for stock 340 heads?

it's not the stock heads that concern me.

the 340 intake was of interest because you might could use it to kludge a Rover racing aluminum head onto a 350. now the TA head will be coming on line as well.


Yeah, sorry too many beers that night LOL... I guess what I was getting at was that the iron 340 heads are the best flowing of the 215-340 heads and that I was thinking of trying to port a set of iron 340 heads in a MAX effort to get the best flowing "BUICK VINTAGE" heads on a high compression 350 bottom end for NA.

I do not think I even need alum heads for my twin turbo and nitrous 350 car since the ported iron heads I am using made 540 hp NA in Sonny Seals car that ran 11s. :shifter:I should be safely over 800 hp.



I just find it hard to believe that someone went to this much trouble to build a 350 with 340 top end to only gain 10 cubes.

if he overheated the 350 and warped the heads and he had a 340 sitting there, swapping heads+manifolds+cam would only require adapter bearings to get going. shouldn't have been that expensive if he was doing his own assembly.

that is a good point though. if it should turn out that this transplant works, a lot of 1961-67 people could get a really cheap bore/stroke job by swapping a 350 short block into their car. and that's something i'm sure the 215 and 300 guys would love.


True, I am hoping that this engine does run!:hurray:



I have a feeling that the cam is still a 350 cam and the person tossed it together because it was what he had.

that's a possibility. which wouldn't disprove the viability of the project but it would certainly render this mule difficult to run. i think it would only fire on 4 cylinders? very rough, if it runs at all.

340=EI,EI,IE,IE vs
350=EI,IE,EI,IE



I was just thinking that this may have been as far as the swap went.... Hopefully he/she thought it through enough to figuer out the cam. :clonk:

randyrhr
11-29-2009, 03:55 PM
OK, I'm back from playing, traveling, hunting, etc, etc. I was able to get the system to rotate and sad to say it is bogus. The cam is a stock 350 and the valve opening/closing is impossibly wrong - couldn't run. I went ahead and pulled the cam and indeed it has all one size journals. This motor was put together well and had all fresh gaskets, etc. I don't think it was done to fool the buyer (me) but rather was done by someone that didn't know any better. It all fit so why not bolt it on there. I suspect the car was for sale because it didn't run after assy or ran so poorly they gave up. It was sold as not running and as I said before, I never tried - just wasn't ever planning to use it. I am sorry to have gotten your hopes up on this one but it was done so well it just looked like something that was "legitimate". I do think that the custom ground cam idea would be very workable and anyone still interested in the possibility of those upcoming aluminum heads going onto a 350 block would be wise to talk to a cam grinder about it. The angle of the push rods between the 340 rocker assy and the 350 lifters are far smaller than the angles we see on many other engines (BB Chevy for example) so that shouldn't be a problem at all. There are reallly no other issues that I can see. Just need to get those valves opening at the right time. Thanks for your patience on this - very interesting thread. Randy

bob k. mando
11-29-2009, 07:50 PM
appreciate you looking into this Randy.

Jim, there isn't any possibility that you could come up with a set of adapter bearings, is there? that plus an old 215/300/340 cam would be enough to get this running.

Jim Blackwood
11-30-2009, 09:02 AM
You could make it run that way Bob but I'm not sure for how long. Still it might be worth doing just to blaze the trail. Randy, if we came up with the parts would you be the guinea pig? I can probably make the bushings but someone else will have to donate the cam bearings and cam.

The problem is that the center lifter bores will be offset from the cam lobes by nearly 3/8" and that is just about guaranteed to cause the lifters to wipe the lobes in fairly short order. The better idea is a custom cam.

I just had a custom cam ground by Charles at Camcraft. Cost me something over $150. He might be able to find you a blank that will work. Camcraftcams.com
Good guy to work with and knowledgeable, none of the hurry you get with the big companies. Very familiar with Buick engines too.

One last thing, did it have 340 or 350 head gaskets? The difference is that the pushrods go through holes in the 350 gaskets but the entire pushrod area is cut out of the 340 gaskets. If it was the 350 gaskets I'd like to know how much clearance there was in the pushrod holes of the 4 center lifters? That will tell us if 340 and 350 head gaskets are basically interchangeable.

Jim

sean buick 76
12-06-2009, 05:14 PM
You could make it run that way Bob but I'm not sure for how long. Still it might be worth doing just to blaze the trail. Randy, if we came up with the parts would you be the guinea pig? I can probably make the bushings but someone else will have to donate the cam bearings and cam.

The problem is that the center lifter bores will be offset from the cam lobes by nearly 3/8" and that is just about guaranteed to cause the lifters to wipe the lobes in fairly short order. The better idea is a custom cam.

I just had a custom cam ground by Charles at Camcraft. Cost me something over $150. He might be able to find you a blank that will work. Camcraftcams.com
Good guy to work with and knowledgeable, none of the hurry you get with the big companies. Very familiar with Buick engines too.

One last thing, did it have 340 or 350 head gaskets? The difference is that the pushrods go through holes in the 350 gaskets but the entire pushrod area is cut out of the 340 gaskets. If it was the 350 gaskets I'd like to know how much clearance there was in the pushrod holes of the 4 center lifters? That will tell us if 340 and 350 head gaskets are basically interchangeable.

Jim

I just tried a 215 head on a 350 block to other day and had a good look. The pushrod alignment is not really THAT bad, some clearancing needed it looks like however not too bad.

Jim Blackwood
09-30-2010, 03:34 PM
Anything new on this?

JB

bob k. mando
10-01-2010, 01:32 PM
Randy hasn't even been on the board since March of this year. so i'm guessing Sean would be the only one left looking directly at this.

sean buick 76
11-21-2010, 11:04 AM
Randy hasn't even been on the board since March of this year. so i'm guessing Sean would be the only one left looking directly at this.

I have not looked into this any further... Interesting however I am set with all my 350 parts...