760 head help!!

[dillmu967]

Can anyone tell me what the differences are between a 61x head and a 64u? Building a 760 to race and I have the 64x 760 with the different compression per cylinder which is not ideal. I read on a different forum that you have to use a 64u head on the 760 can not use the 61x but can not find the reasoning why. Moral of the story I have a 61x head sitting on the shelf and I don’t wanna run out and buy a 64u if I don’t have to. Thanks!

 

[user_error]

This depends on if you are using a stock exhaust or not. Most people that use the 760 cylinder need to use the 701 stock head in order to be able to mount the OEM exhaust. If you are not racing a stock/lites class you will typically replace the head with an aftermarket one.

If you ARE racing stock/lites, you can use either the 61x or 64u head. I cannot list the exact differences between them, but either one will work if you are needing the stock head to mount the stock exhaust.

 

[dillmu967]

Well that’s good to hear thanks man and yes I’m racing stock forgot to mention that

 

[Big Kahuna]

I was thinking the rear dome is larger on the 760, Less compression on it.

 

[hornedogg79]

Yeah and that would be a 64x. 64u is a stock superjet 701 head.

Sent from my Moto G (5) Plus using Tapatalk

 

[Big Kahuna]

I was just seeing the 760 part!

 

[bored&stroked]

a 61x head has 81mm bores, they don't work with the 84mm bore of the 760. You can have the 61x head modified to work though.

 

[dillmu967]

So does that mean a 64u 701 head has a bigger bore then a 61x 701 head?

 

[bored&stroked]

701 is 701. You cannot put a 701 head on a 760 without modifying the domes to work with 84mm bore.