[Johnny406]

Gentlemen,

I will kid you not, this is not my area of expertise but I ran into a situation today while assembling my new 428 Pontiac bracket motor. The engine is a factory 4-bolt 428 block and I am using a old 421 s/d forged crank with Eagle 6.625 floating rods. Both the pistons and rods use a .990 pin. So putting in the first couple of pistons into the motor, I noticed by eye the deck height from the piston to the block was a bit large. I confirmed by measuring it and had a WHOPPING .047. Certainly not good for a n/a motor. My good friend Jack Ferris was trying to help me figure out where the F-up was. I eventually dug out the receipt for these pistons that I bought from the late Greg Merrick (Pontiac Gregg) over a decade ago and they say 428 blower pistons. For whatever reason, I thought they had a thicker crown to go with the very heavy duty pistons.

With my digital caliper and by eye centering it, these pistons have a 1.55 C/H. A Icon piston for this application (428 4in stroke 6.625 rod) has a 1.95 C/H which covers the large gap I found.

My question is: Are/were blower builds built with a lower C/H instead of a dish piston?