new heads power numbers

SVT3183

Member
Mar 30, 2005
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so i had my car dynod at 330 hp and 380 tq at 7# with a completely stock motor. this was without cats and i have since put high flow cats on but not changed anything else. i figure 400 hp would be nice because i crave more but would not be too much where i'd destroy the short block (the tranny will be toast though). if i swapped heads to afr 165's, kept my cam and rockers and intake manifold stock, where would that get me? i haven't seen numbers for a combo like this. what about heads plus a tmoss ported lower? i could always back the boost off a # or two.
 
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I have done the head swap and kept the stock intake and cam/rockers.
Using an equation for 1/4mile ET and weight of the vehicle my car gained approximately 36hp to the wheels.
That's with the GT40 Y303 heads which are probably the lowest performing aluminum heads out of the box for a 5.0L.
FRPP claims 40hp gain and my track runs backed that up easily.

That said, I could see a set of AFR 165s with no other upgrades getting you very close to 400rwhp.

I would suggest the stud mount style rocker arm AFR heads.
Add to that a set of 1.7:1 ratio roller rockers for a little extra lift from the stock cam.
Chances are you'll need a new set of push rods as well.