GT40X aluminum heads?

1991notchbackLX

Active Member
Dec 25, 2007
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New York
can you guys school me on these heads and how they perform? i got a set in a trade that are ported and fully assembled...

the only info i can find is on the ford racing website, and of course they say they're the best head around... how do these really flow compared to Twisted Wedges or an AFR 165?? are they comparable to those heads if they're fully ported? i'd like to put another motor together on a budget and drop it into a vert roller... are these heads worth using or better off on ebay?

thanks for any info

Chris :nice:
 
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AFAIK out of the box the gt40x heads dont flow quite as much as AFR 165s or TW heads, but if the set you have were ported. then they are probably as good or better than a stock TW of AFR
 
With the right cam and intake they will exceed 300rwhp.

Do yourself a favor and take those to the head shop, and let them direct you as to what to do with them before strapping them on.
Pay whatever it costs.

In ported form, they are probably unpredictable, they are not usually the head that people spend a bundle porting.
 
The pitting looks like the spark plug side electrode came off and got hammered between the piston top and the bottom of the head.
 
They would not be my first choice but they are a good head. With some port work you can get some nice numbers out of them. I watched the guys at Panhandle Performance test a set with thier stage I port job on their flowbench. They were just under what a set of stock Avengers they had just tested flowed stock out of the box. I would have them checked but they look completely fixable by the pics.
 
thanks for the info guys, these wouldn't be my first choice either but i couldn't turn them down as part of a trade... my main fox, the coupe in my sig, gets the best of the best, these will be used on a budget build, thanks again!!

Chris
 
can't run them as is? the pitting present that much of a problem? or does it change compression ratio? need to be decked, can't they be just bolted on?

You should never just bolt on any head, that even goes for new ones.
And that rule goes double for heads with unknown work, unknown mileage, and unknown problems.
Look at it as head gasket insurance. If there is nothing needed to be done to them, it won't cost you much to have them checked out.