84mm 61x vs decked 760, any difference?

[bored&stroked]

I was talking to a friend about this the other day. He milled his 760 to get 61x port timing. I asked what the difference between boring a 61x cylinder to 84mm is besides the cylinder thickness at that point. He could only say the exhaust was still "different". So, what exactly is the difference? Will one style make more power then the other or at different rpm's still even with the port timing matching?

 

[Quinc]

Unported the 760 exhaust ports might be bigger?

@Nuklear6 would know, he is the expert on the 760 big bore.

 

[kevbo]

The 760 would still have a little higher exhaust than a 61x . The lower exhaust will offer a little better response at the expense of power if all else was equal.

 

[Nuklear6]

At 84mm it's definitely questionable which is better. The 61x has a little more transfer volume due to the o.d. of the sleeve being smaller. But un ported the 64x sleeve to cylinder casting matches much better and the casting is stronger. Exhaust Port width is similar. Real benefit of the 64x is the ability to go to 86mm safely.

Chuck Palmucci
CPT Enterprise LLC
609 510 3062