redline RPM for buick 340

I have recently acquired a complete 73k mi Buick wildcat 375 340ci 4bbl motor in a "pulling" tractor (1947 farmall M) and have replaced the bearings and checked it out. what is a good redline to shift at stock? after installation of headers and a 230deg at .050 or so hyd cam and springs?(will be using MSD triggered form the points dist, to retain the vacuum advance and a full manual kit in the super turbine 400 and manual pitch control) what chip would you put in the MSD for rev limit? not worried about getting max power (exhibition pulls only, no added weight) I want the thing to sound cool and live a long time because it is such a unique and rare engine. thanks!

stock rods? i don't think you want to go over 6000.

otoh, intake passages are kind of narrow on the 340 ( it uses the same heads as the 300ci ), i'm not sure if it will pull much past that. the Buick 350 amounts to an overbored 340, but it has significantly larger intakes. i think the 340 exhaust looks like it probably flows better though.

do you know if any of the oiling mods were ever done to the engine?

thanks for the help!, Yes, stock rods, no oil mods, (any suggestions?) I will set the rev limit at 5300-5500. I will be removing the heads for valve job and may clean up the ports and gasket match. I will be using 35" tube vertical 4 into one open headers. I actually want to kill some of the bottom end torque and cyl press with a good sounding cam so I can run 91 octane non ethanol marine fuel. I am familiar with big cams, the most extreme was when I ran a 265deg@.050 104deg lobe sep .630 lift mech (AFTER .032 lash) in a cc'd at 7.75:1 comp. in a 440 mopar with a wieand x-ram 6bbl using a homemade top that used 2 1000 cfm thermo-quads in a 4860lb '73 newport as my only daily driver with a coan 11' convertor and 4.56 gears on 87 octane. the only time i took it to the track it ran a 13.41 @107mph dragging cyls 6&8 after 1st gear, haven't ran it since I fixed the fuel dist problem that caused the miss. it will be getting a 275 deg @50 108 lobe sep hyd cam, 10.5:1 pistons, and a 4000 stall and going into a MUCH lightened, 12pt caged 2800lb with driver '64 polara ex drag car that will be driven on the street. But, back to Buicks! most use of the 340 will be at 2500-3000 rpm pulling farm implements that require about 50h.p., the tractor was only 34h.p. stock! The main purpose is to show off the Buick wildcat 375 and super turbine switch pitch 400 trans. at fairs, shows, pulls, and parades, etc. I would like to find decals, new air cleaner pie tin, and proper paint for the engine. for a cam I am looking at the Crower #50233 .448-.501 280-286 deg 112deg cl hyd cam with Crower lifters. what I need to know is, is there a SINGLE spring that doesn't require seat machining or new retainers, (I can cut down valve guides for lift if I have to, no prob.) that will work to 5500 rpm, cam is rated for 7000 ( all rpm usages were based on a 300) and they only sell dual springs that are probably overkill for me and require seat machining. I have spent 2 hrs looking on internet and haven't had any luck. thanks for your patience and help! P.S. I will get some pics of this ugly duckling on here as soon as I can.

no oil mods, (any suggestions?)


most of the Buicks share significant design philosophies in the oil circuit, so most mods that work on one engine will work in some form on another. so if you can find a local guy who knows Buick turbo 6s, 455s or Rover v8s, they can make a pretty good start.

the simplest upgrades are a 5/8s ID oil pickup from a late 70s / 80s V6 and a *quality* ( no Fram ) oil filter such as AC-Delco / Wix / NAPA Gold. you can also turn your filter bypass screw in or shim the spring to give more pressure, although that should really only have an effect at higher rpm. and a higher viscosity diesel oil ( 15w-40, typically ) doesn't hurt either.

after that, you get into stuff that should only be done with a full tear down like drilling out the oil galley passage between the pickup and timing cover and honing out the timing cover passages ( multiples 90* turns between the pump and filter and going back to the block ).

Thanks for the info, I have done similar things to Mopar big blocks, boring them out for bigger pickups, using windage trays (which my 340 already has), making deep sump pans,adding baffles, installing high volume pumps etc. however this was overkill on them for a street/strip motor not running over 6500 rpm and was more essential for round track use. What would be required for use in the 340 at 2500-3500 with brief rare runs to 5300, or will stock system be fine? Are these engines like Chevy small blocks that used valve float to limit rpm. I will be using Crower camsaver lifters with the new cam. (.501 lift max) is there a single spring that will work to 5300?

A note about oil and filters, we raced the 440 for 13yrs and with over 2000 passes and drove it daily to work in all seasons using Shell rotella 15w-40 diesel oil and Napa filters. with that said it washed out the bearings and when I talked to a Shell rep he told me that although diesel oil HAD (past tense) better high pressure wear additives, it also has much higher detergent levels for diesel use that severely compromise high rpm film shear strength, causing high speed bearing wash out, after inspecting several other automotive engines using this oil and 4.10 or more gears I found those same symptoms.
After building over 300 diesel engines and then running them on the dyno, as well as over 100 gas of all brands we found that Napa GOLD filters filtered the best and flowed the WORST due to the fine media. Napa even had to replace several Allis Chalmers tractor engines (maybe others too) nation wide on warranty because of oil starvation issues. my local Napa guy told me this when he handed me a silver filter instead of the gold I ordered. Napa and Amsoil are made by Wix but may have different specs. I would demonstrate this issue by letting doubters see an immediate 20 psi increase in pressure in some engines by doing an oil change and then running the engine, stopping it and then screwing off the Napa gold and installing Fleetgaurd filters on Cummins engines! I can also do it while I dyno an Allis Chalmers 190xt tractor by changing out a new Napa fuel filter for an Agco one and get another 10+H.P. However, we still run napa filters on unaffected engines on the farm because of the good filtering etc.
Currently we run Valvoline VR1 racing oil in the 400 cross-ram motor, and non-synthetic 10w-40 gasoline engine oil with BOTH STP for the ZDDP additive AND Lucas for the film strengh (total additive of 1 qt) in all of our other gas engines.
A friend of mine is an Amsoil rep and their family has been selling it since the '70's to racers tractor pullers etc. I believe it is a good product and would run it in anything EXCEPT an older design engine with either loose clearances (much over.0007) or with high compression on the street! It has superior lubrication BUT vastly inferior cushioning. on the third oil change in my friends new 12:1 440 he went from standard 15w-40 shell to Amsoil synthetic 10w-30 and we headed to town, running it out on the way, he let out of it and I told him his valve lash sounded good (I was running a mechanical cam in mine at .032 lash) then he said this is a hydraulic cam! we looked at the pressure which had been around 100psi before and saw about 65psi! we found nothing wrong with the pump etc and I used it later, but it had wiped out the forged crank in ONE run, it looked shiny like a mirror with no galling and so did the bearings that were hammered out around the rods and mains, but, you could see the bearing oil grooves beat into that forged crank. Not willing to believe it was an oil problem he did it again in another engine later with about 9.5:1 but with loose clearances (no rattles though) about a month after this oil change we had TWO forged cranks that are only good to be ground into strokers which we will not build. The 12:1 motor got a CAST crank and regular oil with STP and has lived many years running a best 11.97 in a full bodied '72 charger. Royal Purple warns about street use of synthetics in racing motors at low rpm.
hope some of my screw ups may help others, results may vary!

he went from standard 15w-40 shell to Amsoil synthetic 10w-30 and we headed to town, running it out on the way, he let out of it and I told him his valve lash sounded good


you're telling me Amsoil killed two forged cranks?

hanh. that's interesting.

we've been recommending Rotella for stockish rebuilds of older cars with NO catalytic convertors ... and getting some dissent for it.

yes it killed two cranks, beat down but shiny as mirrors, he told me to expect to loose up to 20 psi with synthetic, its viscosity rating is NOT the same as for standard oils but is a manufacturer specified "equivalent" (gee I wonder where the MPG savings comes from?!) low viscosity at low rpm and high load = not enough cushioning just like a bad fuel pump diluting the oil till it dropped that much psi. with synthetic for street use on high comp. use at least a 50w then drain it when you get to the track and put in 20-30W, put the drained 50w back in for the drive home! Amsoil is not the only synthetic company that says this as per their recommendations. we still use shell rotella in most of our engines both diesel and gas, most are not high winding or have high comp and have done well for years with a bottle of STP or some other ZDDP additive since it has been reduced in rotella as well. (still a very good oil) ZDDP additive protects flat tappet cams.

1155, thanks for the useful information here as I have been on the same train of thought in using the flat tappets still. I noticed that Mobil1 still has 1300 ppm of zinc in their 15W-50 oils which has worked good until winter time here. You seem like trial by fire has been had a few times, may I pick your brain and see what you think about their stuff?

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Originally Posted by Modernfuse

1155, thanks for the useful information here as I have been on the same train of thought in using the flat tappets still. I noticed that Mobil1 still has 1300 ppm of zinc in their 15W-50 oils which has worked good until winter time here. You seem like trial by fire has been had a few times, may I pick your brain and see what you their stuff?

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Hi Modernfuse
Ask anything you like. I am not sure what you mean by "See what you their stuff" means. Please clarify. We have found in a winter where the temps got at zero or just above that a non-synthetic oil with 15W at the low rating was too thick; we got oil starvation while cold and hurt a couple of motor's rod bearings, one 318 Mopar and a Jeep 4.0 High Output. We can hear one or more rod bearings making a slight noise at start-up when changing oil that goes away as soon as pressure comes up. We now go with 10W non-synthetic at the low end and have not had the problem again.
Back to our 340; we have drilled out the oil passage in the block to 1/2" and will be using the TA Performance larger pick-up tube. We are also modifying the passages in the front cover along with one of their oil pump renewal kits and an adjustable oil pressure pump relief valve kit. I highly recommend that company; you will talk to ladies that are extremely well versed in all parts they have and have good suggestions. They know part numbers by heart. Refreshing in a world where now if it all does not fall in line on a computer a 'parts counter person' cannot help you from experience. We have multiple GMC V-6 truck motors here, probably over 20 from the late '60's and early 70's. We love them because of their high torque. They run in CI from 305 to 478 CI in the same block configuration envelope size. We had a counter guy tell us there was not a V-6 block made he could not carry across the shop. I clued him in on his misunderstanding! You would have to be a serious body builder to carry one of these truck V-6 blocks! I have adapted a 478 CI V6 into a Massey Ferguson 1100 farm tractor. This is the parts guy that then told me that motor did not exist! He then made the further mistake of telling me there was no such thing as a Unipoint set for the big diameter GM window distributor. The Unipoint set (Delco D-1007) has the condenser attached to the point set which makes installation quicker. While this was going on I looked past him to a rack of ignition parts behind him. I told him "OK, just turn around and give me that point set, third row up from the bottom, center". Guess what; it was the Unipoint set!
This is Martin, Dan's dad. Dan is the one normally responding but I have responded here. I am 72 and have worked much like he has all my life both as a professional mechanic, now as a side-line in our farm shop while working my full-time job as a design engineer. This is a great site! Keep ip the good works!

There is a lot of controversy about modern day oils in older flat tappet engines. The ZDDP and the calcium detergent packages in modern day oils are antagonistic. The ZDDP tries to stick to parts, and the detergents try to clean it off. That is why the additives might not be the best answer.

http://www.v8buick.com/index.php?thr...l-tech.222499/

I have been using the Joe Gibbs Driven HR oil in my engine for about 5 years. I have about 30 1/4 mile passes on the engine with no problems whatsoever. I started off with the HR2 10W/30 conventional oil, and now use the HR-4 Synthetic 10W/30.

https://www.summitracing.com/search/...ance-motor-oil

Detonation can beat the rod bearings out of any motor. I never run my car down the track without at least some 110 leaded race gas in it. I would rather have too much octane slow me down than have my engine detonate at sustained WOT.

I have heard more stories about engine failures with Royal Purple than any other engine oil. Never seen it first hand, but I'd never use their oil just based on that. FWIW.

1155, I have updated the post. It's what I get when my kids walk into the office while typing. That's what I was afraid of with the 15w oils but regardless I'm hearing stay clear of a few marketed brands.

Larry70gs, I've been thinking the same thing but looking at how oils perform in stressful heat matters because I know foaming will kill quickly too.

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Originally Posted by Modernfuse

Larry70gs, I've been thinking the same thing but looking at how oils perform in stressful heat matters because I know foaming will kill quickly too.

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Synthetic oil withstands heat way better than conventional oil, and it flows better in the cold as well. Keeping the oil away from the crank goes along way in avoiding foaming. The problem with diesel oils is diesels are low RPM engines, so they may not have the anti foaming additives present in racing type gas engine oils.

thanks for the good info.