stock heads

[Renato Velati]

how much extra hp can you get if you port a set of stock heads?

 

[VadersV6]

Not an easy question to answer. The more power you can make in N/A form, the more you make forced...alot more forced.
Boost divided by 14.7 + 1 = boost ratio.
Use this boost ratio to make a rough power calculation.
20psi/14.7+1 = 2.36
Using this ratio, Ive calulated that the stock TR motor would make about 137hp in N/A form, given the real power number for most TR's was about 275hp....ish
137.5 x 2.36 = 324hp. Thats upping a stock TR motor to 20psi.
Now up the N/A power with mods. Say between ported heads, cam, ported intake, free flowing exhaust and intake, we'll say 180hp. Could be more.
180 x 2.36 = 424hp. Add 43hp N/A, and make 100hp boosted off 20psi.
Lets go to 25psi.
25/14.7+1= 2.7
180 x 2.7= 486hp.
Lets add more flow to the motor so we get 1hp per cube N/A. Not totally out of reach.
231hp x 2.7 = 623hp at 25psi.
Its fun playing with numbers.
The boost ratio is also an important part of picking out a turbo when you look at a compressor map.

 

[Under Pressure]

how much extra hp can you get if you port a set of stock heads?

i gained over a second in a 3500#car with a cam swap also