I have a question....

[1BAD68]

My 390 stroker runs great, lotsa tire shredding torque etc.
But at about 4500 rpm and up it just kinda falls on its face. If I stand on it and manual shift (904 trans) at 5000 rpms, it sqwauks the tires in 2nd and in 3rd but right before I shift I can feel the torque just sort of vanish.
I used my stock 318 heads with a ton of porting and I know that they're not helping much but would I see huge gain in the power band if my engine could breathe better with better heads?
Specs are:
318 .30 over
4" crank
9.5 to 1 compression
stock 318 heads (massive porting)
Comp 284 cam
Edelbrock Performer intake
Edelbrock 600 carb
1 1/4" long tube headers
2 1/2" exhaust
3:55 gears

[firefighter3931]

The intake and Carb are probably holding it back but you could be having a fuel delivery problem. What fuel pump are you running on this engine ? The float level could also be set too low.


Ron

[Plumcrazy]

I agree with Ron, you need a Edelbrock Performer RPM intake or something similar along with a carb in the 700 cfm range.

Also, there is no way for those heads to feed 390 cubes no matter how much porting was done. You need better heads

I can tell you from personal experience that a set of Edelbrock heads will make a huge difference. 

[1BAD68]

I agree with Ron, you need a Edelbrock Performer RPM intake or something similar along with a carb in the 700 cfm range.

Also, there is no way for those heads to feed 390 cubes no matter how much porting was done. You need better heads

I can tell you from personal experience that a set of Edelbrock heads will make a huge difference. 

are there different Performer intakes? I have a Performer but not sure its an RPM.
Edelbrock heads are a bit pricey, are there any alternatives like using 302 magnum heads that I keep hearing about?

[BrianShaughnessy]

Edelbrock heads are a bit pricey, are there any alternatives like using 302 magnum heads that I keep hearing about?

http://bigblockranger.com/Magnum.html

[Plumcrazy]

There's the Performer and the Performer RPM.  The Performer RPM is a high rise design with larger runners.  I believe the name of the manifold is cast into it.  The Weiand Stealth would also be a good choice.

There's a couple other choices for heads other than the Eddy's

Tne next best would probably be the magnum heads, the downside of those is that you have to change your lifters, pushrods and valve covers.  Also there aren't as many choices for intakes unless you have the intake bolt holes redrilled and tapped.

The next best would probably be the heads off a late 80's 360 engine.  Those would have the larger valves and ports, they also have the heart shaped (high swirl) combustion chambers with more quench.  Some porting and 2.02 intake valves and they'd be good to go.