620 big bore kit - purchased!

[POCO LOCO]

Well I pulled the trigger on a set of FBF 88mm 12:1s for my620 monster.I wanted the 11:1s but were out of stock.Does anyone out there have any experience, knowledge setting up a 620 with these pistons (12:1) I am aware that these in a 620 would have alot more of compression Ratio than 12:1 Would I have to shave piston tops, cut for valve clearence, squish ?

[koko64]

Get some pro help to do those very things, (assemble, measure and reassemble to set piston to valve clearance, piston to head clearance, machine piston crowns to set desired compression ratio, relieve and/or resize valve pockets, and squish). You will have plenty of work to do so don't balk at paying a pro to do it right.
It has to be right.

[DarkMonster620]

And prepare the wallet for the hit . . .

[koko64]

So how is it all going?