hi everyone,

this topic deals with piston to deck height clearance...long post

my motor is at the machine shop now. the machinist/builder is a trusted name in the area and has built many Pontiac motors for over 20 years.

my plan is to have the block deck zeroed in relation to the piston top. I have read from many post that "zero deck" or at minimum of 0.010 in the hole is best as it is good for combustion efficiency and quench. also, it will keep the engine cooler and will be less prone to pre-ignition.

so, my engine builder believes that it is not necessary to zero the deck height in relation to the piston top. he believes that 0.020 in the hole will work just fine on pump gas with the cam im using. so, I did more research and have found several post that 0.020 in the hole will work and that I will not have any problems.

im just a bit frustrated/confused now. not sure what to do or think. I guess I can do either as I probably wouldn't notice much difference. right? maybe add octane booster if needed?

on that note, please give me your own experiences and advice on this. if you have similar builds, please help as it will be greatly appreciated.

thanks!!

some might not agree with my build so please don't hate.

my build...

68 firebird
400 0.030 block
#13 heads cc'd at 77cc's
sealed power forged flat top pistons
forged I-beam 5140 rods
summit 2802 cam
1.5 rockers
msd ignition
stock cast iron intake
Qjet carb
TH400 tranny
13" 2500 hughs stall converter
3:55 gears