Ford Mustang Forums banner

1 - 7 of 7 Posts

·
Registered
Joined
·
162 Posts
Discussion Starter #1
With the exception of the 1/2 inch head bolts are the GT40s from the 351lightning exactly the same as the 94-95 cobra 5.0 GT40s? Most importantly, chamber volume, rear smog "holes", springs, valve size etc?
 

·
Registered
Joined
·
301 Posts
The only other difference is they have 64cc chambers vs 60cc for the cobras.
 

·
Registered
Joined
·
162 Posts
Discussion Starter #3
ASAP, some say the chambers are different others say no. The F3ZE cobra heads are 61-63cc according to some websites. So, I can't get a clear answer! The F3ZEs that I have are definitely lightning heads with slightly larger than 1/2 bolt holes. I think I'll just measure them!!
 

·
Registered
Joined
·
301 Posts
Good idea! Are you boosting it? If so, I would, if not, it's not that big a difference. They are great heads for the $$. I just pulled a set of edelbrock performers off and went back to stock gt40's getting ready to sell my truck. The only problem is once I got the engine rebuilt, i'm thinking of keeping it a while longer.....It happens, i guess...lol.
 

·
Registered
Joined
·
950 Posts
I sold my stock lighting heads, but pulled my stang to the track, broke axel on first pass, unhooked truck fron traliler,and ran 13.77 w/4 lb of boost, have not run it again with the gt-40X that i repalced the stockers with.
 

·
Registered
Joined
·
39 Posts
I have ben doing some research on the GT40 heads, what I read was that the lightning heads and the 95 cobra R heads are the same casting. on the 95 R motor they milled the botom of the heads to increase the compression. I have a 94 set of gt40 heads and my plan is to mill them to the smaller chamber size and run the 9 to one like the R motor did. they must have run a better grind roller cam as well to get it up to 300hp that year.
 

·
Registered
Joined
·
901 Posts
From what a guy at FRPP tech told me, the 95 Cobra R was flat tappet cam in a roller ready block as well, just like the Lightning. That never made sense to me in either case.....the Lightning or the R.
 
1 - 7 of 7 Posts
Top