Is there any way to get 300hp out of a 350 with 8:1 compression on a budget? I gave my brother a 70 350 and when we pulled the heads off we found someone had put cast dished pistons in it. It's stampped as a 250HP 350 so I thought it would have had flat tops in it. It has the original 441 heads on it, is std bore, and appears to be in good shape. Is it worth putting a cam in it to try to bump performance up and if so which one. Ultimately this is going in an old 41 coupe (a little off topic), turbo 350, stock torque converter, with 2.90 gears in the rear. He has a set of ram horns but they're the 2" outlet version, an older edelbrock performer, and is planning on running a quadrajet. I have a set of 461 heads that I may let him have to get it up to 8.5:1 and they have 1.94 intakes and were upgraded to 1.60 exhaust valves. I have a friend that will sell a set of TRW forged flattops with the D cut vs the 4 eyebrow valve reliefs for a $100. I'm looking for suggestions on which way to go with this thing. Is it worth $100 on the pistons to bump the compression up? Would it be worth a set of shorty headers on it (Summit painted are $75)?

Thx,

Ted

Ted:

You might want to go here. http://chevyhiperformance.com/techarticles/index4.html
And read through articles about the work they did and the numbers they got with a low compression Goodwrench engine. Lots of basic stuff in here that will give you good info on upgrading your set-up.

Post any questions about a specific component they used and folks can give you feedback of their experiences.

Good luck in your project;

John

ill give it a shot to get you started buy the piston , not a bad deal the 441 heads are good flowing heads for stock heads i believe they were 72cc combustion chambers comp cams 268 cam it is as high as you can go with stock converter the 270 will need a good intake and headers witch i do recamend long tubes, the 461s will work even better with the 1.6 exaust valves if you dont need the bolt holes

Just a tip. All 30 over pistons are not created equally and some might not fit into a 30 over cylinder the same as a different 30 over piston might.

Originally posted by Toby Keen:
Just a tip. All 30 over pistons are not created equally and some might not fit into a 30 over cylinder the same as a different 30 over piston might. :confused: Huh - If you are having your machine work done by a skilled and competent machinist and you are using quality parts (TRW's are good) then a '.030" piston should always fit into your .030" bore' - period. The machinist should have the piston set during the final finishing of the cylinder and will mark each piston for it's bore. There are obviously slight differences in piston finished size due to manufacturing tolerances - but a machinist should correct cylinder sizing for these variations.

No offense meant - but if you are having troubles with this I would change machine shops.

If the short block looks good use the 461s they will be fine. With 2.90 gears you probabily won't want a 268 Comp Cam. Drop down a couple of sizes or no bigger than the 260.

Originally posted by Vintage 68:
</font><blockquote>quote:</font><hr />Originally posted by Toby Keen:
Just a tip. All 30 over pistons are not created equally and some might not fit into a 30 over cylinder the same as a different 30 over piston might. :confused: Huh - If you are having your machine work done by a skilled and competent machinist and you are using quality parts (TRW's are good) then a '.030" piston should always fit into your .030" bore' - period. The machinist should have the piston set during the final finishing of the cylinder and will mark each piston for it's bore. There are obviously slight differences in piston finished size due to manufacturing tolerances - but a machinist should correct cylinder sizing for these variations.

No offense meant - but if you are having troubles with this I would change machine shops. </font>[/QUOTE]Vintage 68, he is right. Different pistons require different clearance between skirt and wall and different rings can require a different wall finish. So the finish bore when done correctly can vary a couple thousandths when setup correctly for different pistons. Read the piston mfr's catalog for their bore specs. If your machinist told me .030 over was .030 over I'd find a different machinist.

For example, when I built my 383 (actually a .060 over 388) I did it with KB pistons. The KB's needed a tight bore. My machinist set it up in accordance with KB's recommendation. Well, I broke a piston a year later and wound up looking for a piston that needed a looser bore than the KB so we could salvage the block. It turns out that the SRP flat tops fit the bill and mfr specs wanted a slightly looser bore than the KB's. So we did a light hone on the cylinder to achieve the correct finish and we were set.

As long as your bore is the same size as or slightly larger than the recommended spec rings should seat OK. The bore can take 15 or 20 or even more wear between rebuilds and still run OK (sloppy but OK). It is not a HUGE deal but 030 is not necessarily 030 ;)

from what i've read- and what my machinist told me 3 years ago when i did my engine- 99 times out of 100, you can set the final bore right at .030 (or whatever) and good quality pistons will slide right in with the proper amount of clearance- within specs, at least.
for a .030 over 350 Chev, for example- the piston will be a few thousandths smaller than the actual boe size of 4.030, to allow for expansion. yes, there are tolerances of a thou or 2 either way, and a good machinist will make everything perfect on the final hone. you "can" get by just slamming .030 over pistons into a .030 over hole, but then everything might not be "perfect", but it will run fine and probably live a good, long life.

With 2.90 gears, go with something like either the Performer cam at 204/214 or up to the Crane 266 at 210!! Your gears will thank you b/c you need all the low end grunt you can muster.. And it will only get moreso if you go taller/wider tires

Imho.. pdq67

I agree with pdq, the Edelbrock Performer cam is an awesome driver cam. It's also available from Summit for 79.95 with lifters. Specs are L, .420-.442 D, 204-214 @ .050, 112 LSA.

I have personally used this cam in the last 3 "daily driver" engines I've built. Really strong low-end.

On the piston issue, most pistons will have the recommended clearance built into them. A .030 over forged racing piston that the manufacturer recomends to run .006 clearance will nominally measure .024 over standard. A stock style piston suggested to run at .002 will nominally measure .028 . Thus a .030 bore (should) work with (most) .030 pistons. Of course you should ALWAYS mic them and fit them to the bore to be sure.

Extra clearance will come into play depending on the appliction. Things such as NOS, blowers,marine duty, intended rpm, etc will all effect what you will want your final piston-to-bore size to be.

I've got the Cranne 266 in my Camaro with 4.10 gears...what a tire roaster!