These engines only had around 180HP - 200HP stock IIRC and am curious what a bone stock '72 350 4bbl w/dual exhaust and 3.42 posi (TH350 trans) would run in the 1/4. I recall driving this car bone stock with single exhaust and (to me) it seemed fast at the time, but I was much younger then.

Just wondering how much hassle it would be to put '70 pistons (or aftermarket) in my '72 350 to get a little more power and compression (say ~9.5:1). Weekend summer driver, concourse type resto (2.73 open to 3.42 posi and duals going to be only mods - maybe suspension upgrades - Hotchkis TVS perhaps, since I have that sitting here still).

Also, how many here put higher compression pistons in their 71/72 350's when they rebuilt the engine?

 

It's your car rebuild the engine the way you want it. You'll be happy with it, as long as everything works together. The higher compression pistons "which 9.5:1 is fine in a street engine", some head work, little more cam, and the 3.42 gears. You will have a very nice running car.

 

Cool car, nice combo. It wets my appetite for stick car Check out this thread as I think it directly pertains to your situation.

https://classicoldsmobile.com/forums...orsepower.html

If you want my opinion, which you might notice I have been regurgitating all over the board lately, I offer 2 options I would look at if this was mine.

1) Cheap route - disassemble engine, have everything cleaned & measured. If it is a relatively low mileage engine or you are wicked lucky, I would consider an almost "cheater" rebuild. Hone cyls(solid hone w/ torque plate preferrably), reuse pistons if you can keep to a roughly .005" cylinder clearance, lands are good, pins not sloppy, etc. Low drag ring pack, maybe resize rods if necessary & if that could be done w/ pistons still on - don't know. Deck block & heads moderately for true & to maintain compression w/ thicker gskts, a little extra for increased compression. Light polish on the crank if dimensionally OK, new bearings, Durabond cam bearings. You would end up w/ a nice loose engine that should work well. What chance you have of being lucky enough to have a short block in good enough condition to pull this off, I don't know. You might have a better chance @ winning Powerball! Basic recondition on heads, slight upgrade on cam - not too much and this thing would really be a nice running car for not a big investment in the engine. I have pulled similar to this off, but you gotta be a little lucky. You keep as much original stuff as possible, for better or worse.

2) Moderate but thorough route - Bore & hone w/ torque plate, possibly a Mahle piston kit that gets you slugs, pins & performance ring package for around $500. There are lotsa other options, I just think that is quality product @ good price that is compatible w/ some restrictions. Chevy rods, I or H beam, crank would have rod journals sized for Chevy rod dimension. This stuff is lighter & cheaper than typical Olds replacement parts & the machine work needs to be done anyway. Machine everything to loose end of factory spec, maybe just a touch looser. Stick w/ standard head recon unless seats need replacement, then I would enlarge the valves "while you are there." Again, if they're shot, you really aren't spending much if any more for the upgrade. Mild cam upgrade, maybe even a mellow hyd roller ($800-1k upgrade when all is said & done, not counting upgraded valvetrain components) if you want to splurge & not worry about oil additive content for the rest of your days. Cam aside, this wouldn't necessarily provide any more performance than "cheater" build but would ensure reliability & piece of mind along w/ really being able to dial in compression ratio exactly where you want it.

Even on a nice resto like you are doing you end up w/ a bunch of non original stuff inside the engine that no one can see or possibly even detect, if you are gonna "really" rebuild it, might as well upgrade vs spend same money to recon 40 yr old stuff.

How far are you from Rochester, NY? There's an Olds guy there that can do you right whether you want to upgrade a little or just simple rebuild.

I gotta get away from this computer!

 

I just had my 350 rebuilt. Went with a W-31 cam, bigger heads, forged flat top pistons, compression about 10:1, Torquer intake, headers, 2.5" mandrel bent duals out to the rear. I am in the break in period now so I have not gotten into it, but it feels good. This cost about $4000.00.

 

Impossible if it's a 350.

 

With a smaller roller regular hyd flat tappet style springs are fine. Roller cam and lifters are about $625.00.

 

I was figuring in machining the block's cam thrust face & installing rollerized thrust bearing & bumper in that figure too.

Agree springs don't need to be special, just high quality.

 

I completely forgot about this thread until now. Thanks for the info. I am still undecided on what I want to do engine wise. Will prob shoot for 9.5:1 compression. I rebuilt the engine myself back in the early 90's and it ran like total crap afterwards. ie. stock low comp. pistons but stuck a big cam in it, which resulted in almost no low end at all. It was a Crane Cam, HMV-272-2 IIRC.

 

I had that exact same cam in my 72 with 9.7:1, it was still lazy. That cam would be better on a 110 and/or with less exhaust duration.

Keep us posted.