head swap question need help asap
 

ok i just purchased a set of gt40 heads and the 1.72 factory crane roller rockers from a 94 cobra. i will be bolting these onto my 87 mustang. will i need to shim the rockers or get different push rods or will my stock push rods work with them. the pedistals and bolts come with the rockers that were used on the gt40's in the cobra.

also what kind of power increase is normal for swaping e7's out with gt40's and the 1.72 roller rockers?

Re: head swap question need help asap
 

Shimming probably isnt necessary. They should just bolt down and be good to go.

They are a decent upgrade over E7's but not huge. My guess would be about 10-12 RWHP with the added lift of the 1.72 rockers and the GT40 heads.

If you still have the stock intake port the lower intake and there is even more HP to be had.

Re: head swap question need help asap
 

i have the performer rpm intake, equal length shorty headers, off road h-pipe, mac cat back, under drive pullies, 65mm tb and 4.10 gears. hopefully it will be a good performance upgrade. still hope it will be a good upgrade