I first would like to say that I did search this forum and on the Web in general.
I put heads on the motor, and I used some solder through the sparkplug holes on all six cylinders, and I get roughly 0.05" cold squish/quench clearance. Will this clearance get bigger after thermal expansion? Or will it get smaller?

 

It should get slightly smaller, within .020" I would say. Which would still give you perfectly fine clearance.

 

Thanks dark_man_x, i hope that 0.020" isnt too small. I read where 0.04-0.035 is ideal.