heads/cam combo advice....

[hfd410]

My 71 has a newly built .060 over 4bolt 350 with 882 casting iron heads. Edelbrock performer intake, HEI, Edelbrock 650 carb, sanderson ceramic headers, 2 1/2" exhaust with magnaflows, and a comp cams XE274H flat tappet cam. I have a TH350 with the recommended stall for the cam with 3.08 gears. The engine runs great and starts immediately however I think it has more to offer. Everything is new and professionally built and I selected the cam based on what I wanted it to sound like vs perform. It sounds incredible by the way....Any help appreciated

[geezer#99]

Lots of cam needs lots of initial timing.
What's your initial timing?

[rickpilgrim]

Ign timing needs to be advanced for best performance.
If your heads are stock and not ported you've likely hit the wall of the 882 heads. XE274 is a lot of cam also, I would expect a weaker bottom end with that. You could also try Rhoda's lifters but that will soften the sound but work with your manifold/ header selection better on low end and still keep the mid/top strong

[Gus350]

To me and I'm no expert but if you want performance you have a good set up on motor . I think you need to look at the rear end 3.08 is grandma gears lol I would think 342'S with a posi would be lots better.

Kevin

[hfd410]

its about 18 degrees initial timing. And not that it matters but cylinders are .040, not .060

[hfd410]

I guess what Im asking is if anyone has an opinion of a set of heads that would help wake it up...maybe some Vortecs ? I dont know much about heads and cams so any help appreciated. I realize that vortecs would be an intake and valve cover change also..

[hfd410]

ttt

[Gimme Jimmy]

Are you using the "dish" top pistons? If so use small chamber heads (65-67cc) some 1.94 327 heads work well for that application. If you are using flat tops, the 73cc heads will render a 9.3 to 9.5 comp. ratio. In any case, a big cam requires high compression to really "thump" and there are several ways to do that using combinations of small block parts that are relatively cheap and easy to come by.

[hfd410]

yes they are dishtop....I guess higher compression would help at low RPM ? It seems to have kind of a "flat spot" in the 1200-2000 RPM area

[rickpilgrim]

I build 2-5 motors/yr for myself and customers so if you were in my shop I would tell you:
Your XE274 cam is 230@.050 intake 236@.050 exhaust with 106 centerline with a rpm range of 1800-6000rpm and power range of 22-2400 to 5800rpm so there are no stock heads without a lot of porting that will give you what you want.
You really need to step up to the Edelbrock head or comparable with 185cc ports and 2.02/1.60 valves with small chambers to provide the neccesary airflow and compression for performance.
eBay that performer intake which is a stock replacement part and get a performer rpm or stealth(air gap in warm climate) which can flow the air needed for your cam.
With this much cam you need 1 3/4" x 28" long headers with a 2 1/2" dual exhaust with x or h pipe with large volume mufflers like flowmaster 50's .
I realize this is a lot of changes to your build, but if you really want it to perform like it sounds this is what's needed to reach that goal
Good luck with your build

[hfd410]

thanks rickpilgrim, I have been wanting to upgrade the heads which I know would wake it up quite a bit. My exhaust fits your specs as I described. Thanks a bunch...

[Gimme Jimmy]

There are very few cams that will increase performance of a motor with 9 to 1 (or less) compression. You will actually decrease performance and driveability by using a cam that is "too hot" for your compression ratio.
High compression improves performance all across the rpm range on practically any engine. Although cam grinders (cam companies) specify lift, duration, etc. they rarely give printed information on how much compression their cam is designed for. I suggest that you should call the manufacturer and ask one of their engineers or technicians what they think. Remember that increased compression practically always requires higher octane fuel.

[rickpilgrim]

As to low compression (less than 9/1) there are a lot of things in cam land that can really help. What you do is find a cam that increases your "dynamic" compression. In my 82 crew cab is a 355 with 8.75/1 compression with ported 487 heads w/ 2.02 1.60 tuliped undercut valves with screw in studs/guide plates roller rockers and stud girdle with double springs. It has a Holley 300-36 intake manifold topped by a Holley 3 barrel carb of 730 cfm or so. Runs dual 3" exhaust with H pipe and 50 series flowmasters.
I've got a crane cam of 226@.050 intake and 234@.050 exhaust with .490 intake .510 exhaust lift . I run Rhoads VVT lifters and have 160 psi cranking compression and it revs to 6500 rpm fairly quick and in that 5800 lb crew cab is ok below 2500 but comes on like a freight train after that and has been checked with a certified speedometer to 130 mph.
It's about dynamic compression and while static helps dynamic is what moves you.

[msgdsrf]

You said 1200-2000 rpm. So thats really just off idle and cruising. Gears will make all the difference. You could also advance the cam a few degrees, that would make it play nice with the low compression. As for heads, that could help for sure but the 1200-2000 wont likely see a whole lot of benefit. 3.73 rear would do the trick.

[bigsnookmaster]

I would go with small chamber World Products Sportsman II heads, Performer RPM Intake, and a 3:73 rear. This would wake things up quite a bit!

[Econman]

With the dish pistons, you'd improve performance with Vortec heads.

[67 chevelle]

Originally Posted by bigsnookmaster

I would go with small chamber World Products Sportsman II heads, Performer RPM Intake, and a 3:73 rear. This would wake things up quite a bit!

great advise