[Driver_WT]

Hello everyone,

I need some help with cam selection for 1975 SBC 355, stock heads (ported and polished), Edelbrock 2701 Performer EPS intake, Edelbrock Thunder Series AVS 650 carb with vacuum secondaries, block hugger shorty headers (unknown brand), 8.5 to 1 compression ratio (as per previous owner). The engine is in a 1984 Fiero with 4 speed manual trans and final drive ratio of 4.11. 16" wheels with 225/50/16 tires on the rear. The headers dump into a Y pipe then a single magnaflow muffler (I can't really upgrade the exhaust system much due to lack of space). Current cam specs are unknown. Engine seems to run out of breath at around 5000 rpm which comes quickly with a 4 speed trans and 4.11 gears.

I also have a five speed Getrag trans that may be a future upgrade for the car. This is a street car, no drag racing. But I would like more torque and improved throttle response. Reasonable fuel economy would be good as car has only an eight gallon fuel tank, but fuel economy is not the overriding concern.

What would you recommend for a camshaft? Engine has to come out for a cam change (have to drop entire rear cradle with engine, trans, rear suspension, etc.), so nothing too radical that would have the possibility of wearing out quickly.

Thanks.

Wade

[75gmck25]

You have a fairly light car, and with that gear ratio, 4 speed, and tires you will always have plenty of RPM. However, the stock heads will limit the flow and the power you can produce. I would probably use a cam with a duration in the range of 220-230 @ .050, with a moderate lift (.50 max?), but I prefer to keep decent vacuum and idle quality. Something along the lines of the comp cams XE268H, or even the XE274H may be what you want.

Bruce

[cdminter59]

A cam such as this one is recommended because of the low compression numbers. Summit Racing SUM-K1101 - Summit Racing® Cam and Lifter Kits - Overview - SummitRacing.com

[vinniekq2]

Because you asked for more RPM I would look in this area
110951-08 NA 275 285 221 231 .470 .470 108 104 Hyd. Hyd. 1
1800-5800 Good idle, Strong Street performance. Needs 4 barrel, headers & lower gears.
the 5 speed will make up the mileage issue,though dont expect to have high mileage and higher RPM and more power.To make more power you need to burn more fuel

[Driver_WT]

Thanks for the replies.

Sounds like I need to save up for a set of heads (since the engine will have to come out to put in the cam; also need to remove the engine to replace the heads as it is too tight to get to the front head with the engine in the car sideways). Any thoughts on the best heads (Patriot, Dart, Edelbrock E-Street, Jegs aluminum 180 cc intake port 64 cc chamber)? I figure I might as well go aluminum for the weight savings and better performance. And does this change your cam recommendations. I was hoping to do just the cam, but if the heads are going to be the bottle neck and I have the engine out, I might as well (spend another $1500). I am assuming I need new rockers, push rods, intake manifold gasket, head gaskets, and head bolts?

[vinniekq2]

How much more power do you want? Heads are a great way to make power,,,I use dart heads on my engine.AFR heads are really good out of the box.
remember,more power means using more fuel.

[Driver_WT]

Originally Posted by vinniekq2

How much more power do you want? Heads are a great way to make power,,,I use dart heads on my engine.AFR heads are really good out of the box.
remember,more power means using more fuel.

325 - 350 hp, 350 375 lb ft torque would be great. And I am thinking that the AFR heads would use up my entire budget before I got to rockers, push rods, gaskets, head bolts, etc. This car is a toy that I would like to get working good, but I will not recoup any investment in high dollar improvements, so I would like to go with good, but not the best parts. If one of the $900 set of heads will make a big improvement, I would prefer to go with them versus AFR for max performance and significantly more money.

[vinniekq2]

If you are removing the engine anyways,consider a quick freshen of the engine? For 350 hp use a set of modified GM vortec heads and a small cam like mentioned above.No need for expensive aluminum heads.This will also give you a chance to see exactly what is inside the engine.
also check to see if the engine was balanced

[cdminter59]

Pulling the heads would be the best idea. You can see what type pistons you have also. If they are the stock D-cup pistons you might want to use a set of Vortec heads. They have a smaller chamber that will boost your compression ratio. Then you can use a higher duration camshaft. This Howards camshaft would be good to use after you get better heads. Howards Cams 112581-10 - Howards Cams Hydraulic Flat Tappet Camshafts - Overview - SummitRacing.com COMP Cams 12-238-2 - COMP Cams Xtreme Energy Camshafts - Overview - SummitRacing.com COMP Cams 12-246-3 - COMP Cams Xtreme Energy Camshafts - Overview - SummitRacing.com All the cams above should put you in the 350+ hp and 400 lbs of torque range.

[ap72]

These heads: http://www.kmjent.com/cart/assault-r...0-383-400.html

And which cam depends on what pistons you have, if you have between 9:1-10:1 final compression I would go for something like this cam: Lunati 20080721 - Lunati Hydraulic Roller Tappet Camshafts - Overview - SummitRacing.com

[Driver_WT]

Is that $600 for a pair of assembled heads shipped?

Originally Posted by ap72

These heads: Assault Racing Complete SBC Small Block Chevy Aluminum Cylinder Heads Angle Plug 350 383 400 - KMJ Performance

And which cam depends on what pistons you have, if you have between 9:1-10:1 final compression I would go for something like this cam: Lunati 20080721 - Lunati Hydraulic Roller Tappet Camshafts - Overview - SummitRacing.com

[techinspector1]

This site has a little age on it, but I still consider it a valid place to go to determine what you want and the parts to get there. All the combinations have been dyno-tested and all of them are pump gas friendly. There are 109 of them, so you should be able to find something that suits your needs......
Ryan's Small Block Chevy Stroker Engine Combo Page

[ap72]

Originally Posted by Driver_WT

Is that $600 for a pair of assembled heads shipped?

Yes it is. they're a little large for your goals but they'll work just fine. Those heads are better than the Procomps from what I've read.

[Silver Surfer]

AP, you don't think the 200cc runners are going to be an issue???

It is going to take a big cam to make use of that. A big cam is not going to like that 8.5:1 CR.

[my87Z]

I too think it is likely your heads that are limiting you and not really your cam.

here is a set of heads I would recomend:
EngineQuest, Performance Chev SB Vortec Heads, 170/64cc, Pr.-Competition Products

RHS used to make a great vortec style head but they have discontinued the model

the EQ heads that I posted accept the early intake bolt pattern and use perimeter bolt valve covers (so pretty much you can use the same intake and valve covers you have now) I'm not sure if they require self-aligning rockers or not but they can had for around 80-110.00 a set. to go with this I would recomend going with a roller cam since you mention that it is so difficult to get the motor out that you would rather not have to do it again anytime soon. the flat tappet cams have a tendency to wipe out with todays oils if not properly taken care of.

either way here is a hyd roller cam I would recomend:
Howards Cams 113215-10 - Howards Cams Retrofit Hydraulic Roller Camshafts - Overview - SummitRacing.com
Howards, Street Retro-Fit Hyd. Roller Lifters, Chev SB-Competition Products

here is a decent flat tappet cam and lifters
Isky Racing Cams 201264-27112 - Isky Hydraulic Flat Tappet Camshafts - Overview - SummitRacing.com
Howards Cams 91111 - Howards Cams Performance Hydraulic Lifters - Overview - SummitRacing.com