I pulled the 305 and am finally ready to build my 350. The motor is out of a 71 Caprice. The heads are "993" casting with 1.94" valves. Im keeping those heads and am just gonna do a valve job on them. I was wondering what compression and cam to do? It has to have all the CC carb and dist. along with all the sensors and computer. The rear is a BW 9-bolt with 3.45 gears and a posi. The car has a 5-speed out of a 91 Formula with a new centerforce clutch. The exhaust consists of Edelbrock headers and 3" y-pipe high-flow cat, and 3" flowmaster catback. I want to run consistent mid-13's with the car. I am located in Phoenix so I am at sea level. I was running 14.90's with the stock LG4, exhaust and the 3.45's. So I think it can be done without too much work. Please give me suggestions as far as good emissions legal cam that makes good power and such. Also the compression. I cant find any pistons over 9 to 1 for 76cc heads. How do you figure compression from 64cc heads to 76cc? Is there a formula? Please help me out here as I am ready to buy the parts and build it. Thanks all.

 

Nobody has any ideas?

 

Why are you hell bent on trying to build a 350/375 horsepower engine with old 200 horsepower heads???
Ya can't get blood out of a stone.

Here is a combination that will run mid 13's. It will be fine with your CC carb. And be a joy to drive every day.

350 ci motor
Federal Mogul Hypereutectic flat top pistons H345p
"0 decked" block (pistons come right up to the top of the block)
Vortec heads (S/A rockers Replacement valve springs, shortened valve guide boss)
Professional Products Cyclone vortec intake PN#52007
www.professional-products.com
Crane Cams Blue Racer cam (214/224@.050" .442"/.465" 112)
http://www.blueracer.cranecams.com/


This recipe is easy, low buck and fool proof.

 

....

 

Well first off, I need to pass emissions and the Vortec heads dont have EGR support. I dont want to run tubes and pipes from my exhaust to my intake manifold. Not to mention, the only reason the early 70's motors were rated so low is ...(1) GM rated the horsepower differently from 71 on, (2) the "993 heads are proven to be good performers, (3) Most of the reason the motors from 71 on were so bad was because of 8.something to 1 compression and the weenie cam they used in them. Now with 9.5 or so compression and a good cam you cant tell me this car wouldnt be at least high 13's. All I wanted to know was if the 9.5:1 was ok for my car, and I wanted a few suggestions on a good cam. Will someone please help me out here? I need to find out what parts to order and order them so I can get my car running again. Thanks in advance.

 

Yes, that setup should let you run 13's at sea level. 9.5:1 is the highest compression you want on a street engine using premium pump gas. The engine I have in my car now is only 8.5:1 and thats with 40 over pistons and it should be high 13's low 14's at my altitude runs great on 85 octaine too. I cant reccomend a cam that will meet your emmission needs but the comp 270H would be a good one IMO.

 

I thought you could go 10:1 on premium gas?

 

Depends on what type of heads ya got. From what Ive been digging into if your running cast heads 9.5:1 is the highest you want to run on pump gas, 10:1 is the highest pump gas compression you want with aluminum heads.

Note to self: Win powerball and buy VP tanker full of RED.

 

The bigger the duration on the cam the more compression you can and need to run. Static compression is good for referencing but knowing that adding duration to the intake lobe reduces the dynamic compression is important. A mildly camed motor may ping with 10:1 static compression where a cam with 230 deg at .050 will probably be ok on 92 octane.

 

Well, I think I decided on a cam. The Crane Compucam 2040. This is an OK cam right? Remember I need to stay emissions legal. So that, the 9.1:1 compression and maybe a Weiand Action Plus intake, combined with my exhaust, 5-speed, and 3.45 gears...ya think thats a recipe for 13's at sea level? If so, I'm gonna order everything. Thanks for your help everybody.

 

id say the comp cam XE262 or XE268. ive got the 262 in my daily driver 305, and it runs like a champ.

 

I'm running this cam. I love it!!! Alot more torque and HP down where it's useable. I've passed smog here for two years straight, and they test for Nox also. You may be able to take a step up from the 2040 with a 350, so far as lift goes.

It comes with a sticker to attach to your radiator shroud that gives the CARB EO number that says it's legal, so they can't fail you for that. My state does'nt do underhood inspections though anyway.

 

Dont 4th gens have over 9.5:1 compression? People use regular 87 octane in those with no problem. Maybe the computer controlled ignition allows this?