Those are the lowest compression height forged 440 pistons TRW sold.

With 88-90cc open chamber heads and .040 gaskets it could easily be under 8:1.

The c/h spec I found is 1.926, which would put it down the hole .150 +/-....... Which is 36.5cc. @ +.030 over.

With an 84cc head, .040 gasket, +.030 over bore and an uncut block, it's 7.95:1.

Basically, it's a forged replacement piston for something like a 76-78 motor.

Depending on what the goals for the car/motor are....... It might be worthwhile to swap them out now.
Or..... Add some boost maybe.

Swap to some 75cc E street heads, .027 gaskets gets it up to 8.65.
Mill the heads to 70cc gets you to 8.98.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads