The issues caused by decking the block and milling heads to me are not worth the trouble they bring.

D I appreciate the information but I'm looking for off the shelf parts. I'm looking to get the max performance from what parts are readily available, if that maximum is a few horsepower less than custom parts so be it.

It looks like 76.75mm pistons are available via eBay, they appear to be the 1mm deep,dish which are around -2.75cc and with those it's possible to get the compression up to 10-1.

The goal is to get a near as possible 1300cc putting out around 90whp. The 1171cc GX motor with the flat slides and ported head made 73whp, so I think it's doable.mthe motor going in the car now is probably near 80whp.

I won't be doing anything until after my next race; I previously made the top 6 overall in the small bore group with the A12, I was finishing 12-15 seconds ahead of the cars behind me and about 12-15 seconds behind the cars ahead of me. If I manage the top 5 or 6 then I will leave the motor alone unless I'm within 4-5 seconds of the next group of cars