Anyone running GT40 X-303 heads??

[M94GT]

ANyone running the aluminum GT40-X303 heads on a stock short block? I just picked up a set,, but am concerned about the 64cc chambers, lowering compression. Trying to get input from people using them and what is your combo?

I plan on using them with a Ford Racing SVO intake(basically cobra), TFS stage 1 cam, 1.6 rockers, 65mm TB and 24# injectors and matching MAF meter.

 

[IceMan]

They will lower your compression a bit but not too much... I have the same heads with an Edelbrock intake F303 cam Scorpion 1.6 RR 70mm TB but I have a turbo as a power adder... You will gain power form adding them on and not lose power from the lowered comp. You will be fine...

 

[IceMan]

BTW I think they came with 64cc and 58cc chambers... Might wanna check on that though...

 

[Lee12609]

You will be able to run more timing which will make up for most if not all of the compression loss.

If your getting a good deal jump on them.

 

[LAFENATU]

FRPP quality is superb so quality is not an issue. As far as 64cc chambers it isn't going to lower anything from where you are now.

As far as power they are comparable to a Edelbrock E-Street head. If you invest in some portwork, it will wake them up. If you're worried about the larger combustion chambers, you can get the heads milled.

 

[M94GT]

Thanks guys.. I did get a good deal on them, and was considering having them milled to compensate. Anyone know if there any part numbers or identifying markings to tell difference between the 58's and 64's???

 

[BlkoutGT]

X305 is the 58cc and I believe X303 is the 64s. The number should be on the heads in where your valve springs are.

 

[Win]

I will soon be running the X303 heads when the new motor arrives.

 

[M94GT]

X305 is the 58cc and I believe X303 is the 64s. The number should be on the heads in where your valve springs are.

Thanks,,, heads I got have the x303 part number.