heads ??
 

just woundering and making sure of the heads i have.

ok how do u tell if you have gt 40 or gt 40p heads and what ones are better?

i thought it was the lines on the front of the heads but now i forget and wound like to make sure

thanks mike

Re: heads ??
 

Gt40 has 3 line and p has 4

Re: heads ??
 

Also GT40 have angled plugs and GT40P's have straight plugs.

Re: heads ??
 

And P heads have a "P" stamped in between #1 and #2 spark plugs.

Re: heads ??
 

thanks very much i have the gt 40 heads b/c of the angled plugs on them. now are they better then the "p" heads? ( for flow etc.)

thanks alot again

Re: heads ??
 

also i was thinking of putting roller rockers on how do tell the size of stud ( just measure it) ? also what size should i get 1.6 or 1.7
thanks

Re: heads ??
 

Stud size is either 3/8 or 7/16. I am thinking it is 7/16. I run 1.7 roller rockers

Re: heads ??
 

You mean the factory pedestal?
It's 5/16, you wont need a stud unless you convert to the stud conversion, you have bolt down rockers.
1.7's work for me, but im foing to 1.6's and really dont know why lol.
To answer the question, the p is a better flowing head due to the angle on the plug , some people will argue, but #'s dont lie, the non-p has a bigger exhaust valve that responds to porting quite well, so ported 40p against ported non-p is probaly pretty close with the p still maintaining better economy.