AFR 165 vs. GT-40X

[eightyfour]

Would I gain much HP swapping out GT-40X heads for some AFR 165's?

 

[umstang]

Your going to be able to noticeably feel a difference in the car. Do it

 

[CRASH7772]

On a motor that made 306hp@5300 (avg hp 253.08)and 342tq@4000 (avg tq 316.00) with E7TE.

GT40-Y's made 353hp@5600 (avg hp273.75)and 363tq@4200 (avg tq338.19)
AFR's 165's made 396hp@5800 (avg hp288.89) and 342tq@4700 (avg tq353.86)

This is out of Sept 2003 MM&FF. I know the X's flow better than the Y's but I thought this info might help a little.

 

[CRASH7772]

I just found flow numbers on both all from MM&FF.
.50 .100 .200 .300 .400 .500 .550 intake@28"
GT40-X 30 57 110 162 193 215 222 ([email protected])
AFR 165's 30.5 58 122.5 178 213.2 237 240

 

[PURESTREET5006]

And if you port those AFR 165'S...Man, hold on to your hat!!!

 

[Highbredcloud]

I was curious myself since I have GT-40X heads 64cc, however, they are ported and polished, and made about 20RWHP less than avg. AFR set up...that was without tuning but still...THE only difference I can say for sure is that the AFR's are 165cc as oppose to the X heads being 178cc so AFR's will feel better in lower RPM's...keep in mind that X's are not ported like the AFR's...for the money AFR's are a better head...but don't exclude the X's...they are really good even though overpriced...

 

[87gn2]

Why port 165s when you can get 185s for the exact same price?

 

[Highbredcloud]

Why port 165s when you can get 185s for the exact same price?

Just as my previous post a smaller head will make more TQ down low and will keep pulling hard uptop once ported...simple...velociyt along the cc's of the head determing the powerband...

 

[90mustangGT]

I would choose the AFR's over GT40's anyday. Not saying the X's are not good but the best results I have scene is with the AFR's. There is more than flow numbers to take in consideration. The AFR 165's flow as well if not better than many other heads with larger CC ports. The smaller size will make more velosity which is definatly important.

 

[Legendary]

So is it better to get the afr 165s and port them vs. the afr 185's? This would be for a forced induction car.

 

[NeQX]

So is it better to get the afr 165s and port them vs. the afr 185's? This would be for a forced induction car.

Depends on size of block, 302-306 go with 165's, 331 or so forced use 185's

 

[eightyfour]

whoa! ok thanks! btw, this is on a GT-40X crate motor. so will i need pedestal mounted or stud mounted versions? thanks!

 

[GT40XStang9]

Crate motors come with pedestal mount rockers.