I have a couple questions regarding this engine, namely the compression. Is it actually 10.25:1? What octane is generally run in a Buick engine like this? Also, what are the cam specs? Are the chambers 58ish CC like all 350s? Can I swap to a later style stamped steel rockers if need be? I've heard these had .020 thick headgaskets, is that true? Any input is appreciated.
No its not actually 10.25, a bit less from what I've read and heard. I would not run regular gas, try mid grade, then premium, see if it pings. BUT all this is dependent on your timing, and the condition of your distributor. Read Larrys Power Timing Thread All 350 heads are pretty much the same, no special High Performance heads were made by Buick for the 350. Yes you can swap to stamped steel rockers. STOCK 350 GS cam specs are in the Buick Chassis manual for your year. Yes, steel head gaskets were original, .020 All of the above is based on if the engine is indeed UNTOUCHED ORIGINAL
That's pretty much what I was looking for. And, afiak, the engine is an untouched original I'm looking at. 70k miles on it. Won't really know until I get my hands on it in a few weeks, but the guy sounds trustworthy and the pics look good.
I've put in the specs of the 350, along with the .020 head gasket into a compression calculator, and it only gets 9.7:1 static compression. Dynamic is just over 8:1. I plan on regasketing the motor, with the felpro .040 gaskets and that brings it down by almost half a point with the gaskets being around .040 thick. I think I can get away with 93 now that I think more about it. Timing would just be a new TA HEI dizzy, no points here. 22* advance starts at 1000 all in by 3600, might play with it in accordance to that power timing thread.
9.7 is reasonable. I would leave that alone. As far as timing, change curve to 26-2800 . Don't forget that these engines had a slightly higher torque converter and 3.08 gears . Which can change octane tolerance some as engine not lugging due to steep gears ment for mpg not power
If you were concerned about ping I wouldn't put lighter springs in the advance without proving things first and taking proactive steps aiding safety margin
You can always use a light spring and a middle spring to help taylor in the timing. The springs with the loop at the bottom of the spring are junk, the loop of the spring should be in the middle of the spring like the originals.
You won't know anything until you get it in a car and run the complete combo of your car and it's tune. Then you can tune it for your fuel and trans/rear. otherwise you can't gauge anything. You can guess all day long.
I would suggest to the OP to start his tuning from the side of slower timing curves, and conservative tuning practices, then work towards the direction of aggressive...after making the entire package more suitable to push the boundaries. 'Not a guess' (Didn't mean for this to read so confrontational, just don't want to see a thread called "why are rod bearings so inferior these days" or something like that) Definitely great advice to get hands on and not jump on the advice that you agree with the best.
Before its in the car and still on the engine stand, leave head gaskets alone as in DON'T remove heads, the compression it has is a great foundation for better parts! DO remove timing cover and replace the factory timing chain and gears before you spend the time to install it in car! While you're there perhaps consider a different cam that would better suit the compression ratio with todays pump gas? The TA-413 would be a sweet cam with that ratio and good with premium pump gas or the TA-290-94H would have a little better street manners with slightly better fuel economy running the same fuel. Or a Scott Brown custom for your combo for about $20 more he can possibly get you better economy AND better performance than either cam for your combo. The small factory cam with that much compression may get challenging with your combo and pump gas? A WHOLE LOT easier swapping a cam with the engine on an engine stand than doing it with the engine still in the car! GL Derek
Timing chain is a good idea. I think the stock cam would be ok for now. I think op should see what he's got first. As in how it runs. It may be enough for him. Especially with not knowing what trans/ convertor combo he wants and rear gear. Factory those engines had a 3.08 and alittle more converter. Not much but enough to change how the engine rpm range will be in his vehicle
Th350, 1100 stall with a shift kit, maybe come governor mods to shift at WOT in drive at 5000. 2.41s. Next summer however will be 3.42s and a 2200ish stall. It's going in a 1985 Regal.
Well with an anemic rear gear like that you will more than likely experience "pinging" that will be hard to tune out without a cam change. You don't want to go to much bigger though so either the TA 284 or the TA 290 to maintain low end torque so its not to much of a dog from a dead start because of that gear, maybe even the TA-212 if the dynamic isn't to high? Should be a fun car next summer! Derek
I'm thinkin, if this motor really is as good as it seems, and really only has 70k miles on it, (let's face it, no one hardly ever drove these old cars past 100,000 miles), if the bores and bearings look ok, I think I'm just gonna get the heads spiffed up with a good valve job, new valve springs, and either that TA 284 or TA 290 cam. Along with all new gaskets and seals of course, plus an oil pump rebuild kit of the TC is ok. I will install a new front cam bearing though, if needed. Which it probably does.
If your going to go thru engine, might as well upgrade front and rear seals from rope to neoprene and do the block oil passage and pickup screen.
