I am pleased to announce that I have received a verbal commitment on a new forged 400E and 425 piston. Sizes will be 4.100" and 4.155" respectively and have the following specs, although not carved in stone quite yet.

4032 material
.980 pin
1.620 compression distance
8cc D shaped Cup and the most modern ring pack available today, 1.00mm, 1.00mm, 2.00mm all steel ring set.
Price would be in the $600.00 range which would include pistons, pins, clips AND rings. Overall piston weight would be significantly less than all the current pistons available.

Compression would be in the mid 9 range on a 400 with stock heads and the pistons approx. .020 in the hole. A 425 will have upper 9:1 compression.
The goal is one configuration for all applications.

 

Good to hear! I love the 425s and have two of them that I plan to rebuild as soon as the budget allows. Lighter pistons and modern ring packs, yes, that's going on the rebuild parts list!

 

It is good to have choices. Thanks for your effort on this.

 

Very cool, Mark. Given the compression height, I assume these would also work in a 350 block with stock length rods.

Edit: OK, never mind. I just saw the other thread in the small block forum.

 

The mid 9 CR is ideal for the street. I have a CR of 9.66 in my 66 400 tri carb and it made 475 ft#'s of torque, 411 HP with VP110 & 406 HP with Shell 93 on the pump. I run 36 degrees of advance with no detonation issues. Sounds like good pistons to me.