1g-gte bore question

[gc8_g_r]

HI,this is my first thread,say hi to everybody.

Here is my question, I am going to bore up my 1g engine..thinking about using 78mm piston or 77mm piston.

78mm piston is HKS,not forged, cast, all hks 78mm 1g-gte piston are cast, hks 77.5mm piston comes both forged and cast , just read original HKS 2G full instruction sheet.

77mm piston is custom made forged, also it's got an advantage, i can use stock bore gasket, most stock 1G engine gasket is 77mm bore, no worry about finding 79mm gasket.

The main thing I worry about is cinlinder wall...78mm is too thin? friend in japan tried 79mm piston, after installation, just started the engine, then leaking air..

Any suggustion?

Hope I get more 1G info and friends here.

cheers