sawracer wrote:
Wonder what they were thinking?
As mraxl has stated, you will really have to know at what position your ports are as compared to a stock cylinder.
Whoever did this ended up with a 2mm lift on the transfers and the exhaust port and minus 2 on the intake port. The piston would have to be cut 2mm just to restore the stock timing (which it appears it was, and then some) unless the intake port floor was lowered.
Depending on how much the exhaust was
further raised your engine may have been far from a dog! The stock squish gap sucks anyways so your excessive gap only controls the compression ratio..
If you return to single stock gasket you may now have a too severe piston cut, as lowering the cylinder will increase intake duration on its own. This will likely mandate new pistons.
You may want to make a correct cylinder shim as suggested. If you don't want to deck the top of the cylinders (so you can go back to close to stock with new pistons) you can re-work a head that actually sits down the bore to correct the squish gap (aim for around 1mm).
If you like the setup the final optimization would be to lower the bottom edge of the transfers and the exhaust floor (if they have not already been done) at the bore back to the stock position (typically close to flush with the piston crown at BDC).
Depends on what you want. With big carbs and chambers (that actually work) it appears you could very easily end up with a high HP high rpm screamer.
J