Boring the MAC84

[tnrcboatracer]

HAs anyone 'bored' the MAC84 by swapping the P/L with one of the 90 sized sleeve sets? Just thinking out loud here.

 

[henry velasco]

I don,t think it would be a good idea -- the 84 is a 67 case bored out and is prone to breaking as is

Henry

 

[tnrcboatracer]

I didn't know if the OD of a 91VAC liner was larger in OD than the MAC84 sleeve. I know that the latest molding of the MAC 67/84 case was a little bigger, and the inner port cores were different. Andy confirmed that to me. I already have an early silver head 67 case that was bored to accept an 84 sleeve. THe port velocity should be very hight on that motor. Just need to finish it.......

 

[Don Ferrette]

I didn't know of the OD of a 91VAC liner was larger in OD than the MAC84 sleeve. I know that the latest molding of the MAC 67/84 case was a little bigger, and the inner port cores were different. Andy confirmed that to me. I already have an early silver head 67 case that was bored to accept an 84 sleeve. THe port velocity should be very hight on that motor. Just need to finish it.......

I believe the VAC91 liner o.d. is 1.260"

 

[henry velasco]

I didn't know of the OD of a 91VAC liner was larger in OD than the MAC84 sleeve. I know that the latest molding of the MAC 67/84 case was a little bigger, and the inner port cores were different. Andy confirmed that to me. I already have an early silver head 67 case that was bored to accept an 84 sleeve. THe port velocity should be very hight on that motor. Just need to finish it.......

I believe the VAC91 liner o.d. is 1.260"

If that,s the size then that means another .040 per side has to come out of the Mac case -- man i,d be scared of that

Henry

 

[dwilfong]

Don't do it. It will pop the top off the case.

The HR sleeve is smaller in OD. 1.220 only .040 total .020 off each side.

David