View Full Version : how to beef up the 340

09-08-2010, 08:32 PM
i have a 340 engine and i am looking to beef it up and get as much horsepower out of it as possible. i in the process of restoring a 66 skylark and in need of some ideas on how to improve performance of the existing 340. anyone please help. if it is better to trash the motor and get another one please advise of that as well.


09-18-2010, 08:08 AM
I just acquired a 1966 Skylark with a 340 4v V8, as well. After doing a lot of research, there are many ways that the 340 can be improved for more horsepower.

Search around the forums on this site for links to headers, exhaust, engine overhaul kits, and the like. Also, get the parts catalogs from Year One, TA Performance, Original Parts Group, etc. and you will find what you need. Of course, Internet searches for specific parts and modifications will help, too.

I plan to get at least 350 hp out of my engine when I do my upgrades. It will take time, but I think it will be worth it to keep the 340 under the hood.

bob k. mando
09-18-2010, 08:59 AM
the 340 is out of the same engine family as the notorious Buick turbo v6 of the 80's, the 215ci stock block Indy car competitor of 1961 and the Buick 350.

though light, it is very strong as it's a fully skirted Y-block design.

the problem is that it was only in production for two years ( 1966-67 ) and there is little to no development for it and very few parts. www.TAPerformance.com (http://www.TAPerformance.com) is on the verge of putting aluminum heads for this on the market ... but that's more because the 215/300/340 design is shared with the Land Rover v8 than because it's for the 340.

which, by the by, finding a Land Rover engine guy near you would be a good idea to have this worked on.

turbo and / or nitrous would be the most cost effective ways to get power into it.



bob k. mando
09-18-2010, 09:03 AM
these are some of the mods that AM&P makes to the 350 block. i'm not sure exactly how much changed between the 340 and 350 beyond the cam and valve pattern.


09-18-2010, 08:03 PM
The previous owner had removed the plugs and set them on the air cleaner cover. Took a BFH to get the pistons out. Was told my my machine shop the 340 has parts but it is much more expensive than say a 350 chev.
I plan on setting a pontiac 400 in it. Any thoughts, opinions advice?

Ted Nagel
09-19-2010, 05:50 AM
Well, you are on a Buick site, so you are asking a bunch of Buick gearheads about engine swaps. So I will say it for everyone here- a Buick engine would be what I like, and all the variety of Buick engines are one of the things I admire about the marque.

I like a 350 Buick or 455 Buick for a swap into your car, I'm a Buick fan so that is MHO.

09-19-2010, 07:06 AM
One of the interesting things about the aftermarket industry is that it gives a lot of focus on Chevy and Pontiac parts and not a lot of focus on Buick and Olds parts. I have always been a huge fan of GM and owned many GM cars. But I would want to keep my Skylark as much as a Buick as possible.

This challenge is not limited to what I put under the hood. The car did not come with A/C so trying to find an era correct system was difficult. I lucked out on finding a 66-67 Harrison Under Dash Unit that would have been a dealer installed option back in the day. The Unit has a "Chevrolet" emblem since it came out of a 66 Nova. But it would still be the same part used by a Buick dealer. Once I take the emblem off and put it in my car, then it will look era correct.

If you are going to use other division parts for your Buick, then it will depend on what you want to replace. The 66-67 Chevelle speedo and gauges are similar as the Skylark. The 66-67 Olds wheels are similar as the Skylark.

The more people demand Buick specific parts for their Buick, then the aftermarket will respond. I think there is an increase of Buick specific parts out there, including parts to restore/modify a 340 V8. I am still doing my research and determining my budgets. But I think that it is possible to keep the 340 V8 and get reasonable increases in performance.

It will be interesting to see what you will decide with the 340 V8. Keep us posted either way.

Jim Blackwood
09-30-2010, 06:01 PM
The biggest issue with the Buick 340 is the lack of an aluminum intake manifold. Any other parts you might need are available including aluminum heads and performance parts like forged pistons. However, there *are* a few IR intakes around that will fit the 340, though very expensive, and a few individuals can and will build custom intakes. With the aluminum heads and intake the engine weight is in the ballpark of 400 lbs, almost exactly what a 302 Ford with alloy heads and intake weighs. So it is a very light engine. It also has great torque production which is a very good thing for any street engine. By comparison the SBC for instance is very heavy. Even with iron heads and intake it is light for it's displacement.


10-01-2010, 07:09 AM

I am curious.

How much of a performance gain would one get if there was an aluminum intake for the 340?


Jim Blackwood
10-01-2010, 07:41 AM
Probably just lose weight, unless it was a true performance intake, then something like the typical gains you see with similar intakes, which usually means moving the "sweet spot" up the rpm range a bit (Claims of 20-50hp seem common). Now if you had something like a ported set of heads such as the Real Steel Merlins or the soon to be released TA SBB heads a good intake could make quite a difference, given the right cam, carb (or efi) and exhaust.


10-01-2010, 08:06 AM

Do you know when the TA Performance heads will be released for the 340?

What will the performance gains be for this product and how much will it cost?


Jim Blackwood
10-01-2010, 11:09 AM
Don't know, and don't know. The Real Steel heads are currently available, cost $2100 and come with valve covers but not rockers.


bob k. mando
10-01-2010, 12:31 PM
Do you know when the TA Performance heads will be released for the 340?

keep an eye on the TA web site or even give them a call. i think they're moving the first set of head castings through machining right now.

this does not necessarily mean that the castings will be on sale within the month or what have you. they still need to iron out all of their CNC programming and QA procedures.

11-22-2010, 06:30 PM
#1 thing, go with an electronic ignition,
#2, TA performance makes some good cams
#3 replace the oil pump housing/timing chain cover with a new one from TA.

if you have the block worked make sure to put threaded oil galley caps in, and loose the "freeze plug type.

I did those mods, and a few others, and in return I have 325 hp. (engine rated at 260 factor)

Sanderson Headers in San Francisco makes headers, and don't forget the dual exhaust. I'f i had those I'd have more power I'm sure.

11-23-2010, 04:42 PM
I definitely have Sanderson Headers on my list and I was thinking of giving TA Performance a call soon.

Which electric ignition set up would you suggest?


11-23-2010, 06:21 PM
I used a junk yard HEI donor, than the Pertronix Flame Thrower ignitor and coil.
Accell wires and cap.
you will have to grind down the corner of the intake manifold and possibly the corner of the drivers side cylinder head for clearance.

you also have to run 12 gauge wire from the fuse box to the HEI.
there is a great site on the step by step, but he does not do this on a 340.
I did following his "guidance" and managed to do this to two cars with the 340.

The wire that runs from the fuse box to the coil now is resistor wire, you can cut it off and leave it in place, just tape off the ends so it doesn't spark on anything.
the section that runs to the starter is not needed anymore either.

sean buick 76
11-24-2010, 10:54 AM
I just want to say that for anyone looking to get performanca out of a 340 engine.... Get the heads ported, Gessler is one of the best look him up.

11-24-2010, 04:53 PM
Most certainly, I had my entire engine re worked, and most of the work to the heads.
hardened seats and new valves to handle the unleaded gas, and ported and polished.

11-29-2010, 10:34 PM
I think an aluminum intake would be great. Not only will it save atleast 30 lbs off the engine, but it could offer a huge improvement with port matching and overall porting of these heads.

Does anyone have any experience with Crower Cams or Isky? Saw some of them listed in one of those large catalogs for the 340.