69CSHC

Quote:

Originally Posted by Fun71

Way back in the 1980s I had to rebuild the engine in my car (350-4bbl) but I retained the factory camshaft. The engine wouldn't pull past 5000 RPM, then I installed a .435" lift, 204º duration camshaft and it was a huge improvement, and with new valve springs the engine would pull well past 5000 RPM.

71OldscutlassS I'm with Fun71 on this, if the cam swap is a must go small. As was recommended to me (along with new timing chain and lifters) he put what sounds like the equivalent of the basic stick cam in his car back then. Been reading Fun71s posts for a long time. He knows both of our cars, has experience in both. I respect his opinion.

71OldscutlassS this move along with everything you have done may get you to about 235 HP or so well tuned. A world of difference versus stock and with the nice go package you put together potentially a 14.7 second car. Quicker than many a stock 442 but still far away from the big dogs. Big dog territory is 300 HP and up, full performance build needed... Now we are talking 13s which was very quick back then and still a healthy mover today.

P.S. the only stock Olds 350 that can touch 300 HP with basic bolt-ons (headers) is a W31 version.

(sorry about these 2 last posts being a bit out of sync with the thread, meant to post this days earlier)

71OldscutlassS

Thats exactly what i think about!

Which spring set would you recommend?
Im a bit clueless in this case. Perfect would be a set from comp or edelbrock which is available on Summit, because for us in Europe, we mostly order our parts on Summit.

My plan was at first to do a full engine rebuild bearings, gaskets and so on and keep the stock crank and rods, just replace the big dished 1971 pistons to flat top or smaller dish pistons to raise compression.

But now, that mostly all of you say that this isnt really worth it, i think i keep my current engine rotating assembly stock and maybe someday i find another good 350 engine or 455 and make my full build then.

So, i think this is the list for my Engine:

- Comp 260H Cam and lifters Set
- New Comp or Cloyes Timing Chain (now i have a Comp single Chain installed)
- New Valve Spring Set like Fun71 recommends (which one)?
- new Valve Seals (which Set is a good choice?)
- Hughes GM20 BPO Converter for TH350 Bolt/Lug Type
- all gaskets/hardware i need for this job

have i forgot something?

im very thankful for help in Parts recommendations

Greetings from Austria

coppercutlass

That 260 h won't pull to 5800. Great cam but dead after 5k rpm. If you wanna spin to 5800 and still pull like a freight train you are gonna need alot more compression and cam. Like 9.5 to 1 + and a cam above 220 duration. Keep it simple my current 355 spins to 7k rpm and rim running 11.6's at the track. It's very rare that I do any burnouts on the street or even go above 4k rpm. Which is my highway driving RPM. Now my pontiac had the same set up I suggested which I also did for a local guy here. And it's a fun car to drive. I enjoy that more than my cutlass with the wild 350. I say this because alot of people start building something and get carried away . Build it modest and go from there. Just my 2 cents. You got a solid plan

71OldscutlassS

I have not that much expierience in engine building, me and my brother built together a 408 stroker out of a mopsr 360, but on this built he purchased a whole balanced kit for the rotating assembly (crank, rods and icon Pistons from scat), so this built was quite a p&p except the machine work for the block.

I was hoping that there is a piston set, which i can use with my stock crank, rods and my #7 heads to get a compression like 9.5. And i thought, when the bores are ok and in good shape to swap pistons without machine work, because this is VERY expensive here in Austria.

So, maybe its better to leave the short block like it is for the moment and just swap to the 260h cam, converter and new valve springs. Its not that important for me to be able to revv it to 5800-6000 rpm, i just want to stop the valve floating at 5000 and a bit more bang off the line. As i wrote in my post before, maybe its a better idea to do this to my matching numbers 350 and get another engine to do the full built with 9.5 compression and more cam.

Thanks a lot for your help, im learning a lot from this forum!

coppercutlass

Do the minor mods it will boost performance and you will be happy until the time comes for a full rebuild.

olds 307 and 403

The Mahle or CP pistons are designed to be hone to fit in the 4.065" size, IF your block isn't too worn out. The CP are basically a flat top with 1.3 mm valve reliefs, compared to the Mahle at 10cc. They have compression height listed but you need to know your head CC as well. Before buying anything, do a compression test and check hot oil pressure, it will tell a lot. Even if you end up just doing the cam and springs, degree the cam, the cam or timing set can be way off.