Piston/compression height?

[dorin48]

Problem: Want a forged piston but nobody manufactures. TRW used to make a piston but it ups the compression, which I dont want. (trying to work all the details out of a turbo build, 1977 Ford 351m)

Possible routes: Custom = $$$$$
Sister engine= different compression height

Basically I need to figure out which piston will work but I am not sure how the math works.

I have a 351m which is identical to the 70's 400 except for the crank(more stroke) and pistons(shorter compression height). The difference in the height is .3 inches. If i were to just put the 400 pistons in I would end up with a 5.5=1 CR.

So the 351 cleveland's pistons are almost identical to the 400's and there are many forged piston options.

Pistons are sold by CR and bore, not compression height. I need to figure out which 351c piston will work in my 351m while keeping as close to the factory compression as possible.

Picking a 351c piston with a higher CR will obviously counter the compression height problem but how much?

Also, will this ruin my quench area?

Important numbers

Bore = 4.00"
Stroke = 3.50"
Combustion Chamber = 78.4cc
Deck height = 10.297

Reps+ around for valid responses.