Avanti 60mm crank

[mick1]

If a 60mm crank was fitted to an Avanti with a 1.5mm base packer would any alternations be needed to the barrel (raising/lowering of ports, etc).

What would be the likely benefits or changes in performance ?

Thanks for replies

[faf]

I didn't need a packer on mine as the squish was spot on without one,had to take 3mm off the piston skirt though as it was hitting the crankcase mouth at BDC!