***273 Commando pistons and '302 heads???***
We took and cut some 1.88s down to 1.84's on my 273 with no problems. I'm usining the L2222 pistons. If you take the stock stats on the Hipo 273 such as the stock deck height, steel shim gasket, combustion chamber on the 920 head etc. you'll find that the actual CR on the stock 235hp was around 12 to 1.
If you have access to a flow bench do a comparison between the 920 and the 302 in terms of port velocity and flow. You'll find that the 920 flows a bit better. One reason I think is the 920 was suited to flow wet air (carb) while the 302 was better suited for dry air (fuel injection). if you do flow test a comparison make sure you use a realistic 18" of vacume rather that the 28" of vacume. That way you'll get a better real world comparison.
As far as I know, they are stock 1.78 intakes...same as the original wedge '920 heads that came off the engine. I could just stay with the 2 bbl ,4 valve relief pistons that are in there now,and use the thin MP gasket (.028 compressed), but I was hoping to try the Commando pistons for a bit more comp. I was concerned about the Commando dome hitting some part of the '302 combustion chamber....
We took and cut some 1.88s down to 1.84's on my 273 with no problems. I'm usining the L2222 pistons. If you take the stock stats on the Hipo 273 such as the stock deck height, steel shim gasket, combustion chamber on the 920 head etc. you'll find that the actual CR on the stock 235hp was around 12 to 1.
If you have access to a flow bench do a comparison between the 920 and the 302 in terms of port velocity and flow. You'll find that the 920 flows a bit better. One reason I think is the 920 was suited to flow wet air (carb) while the 302 was better suited for dry air (fuel injection). if you do flow test a comparison make sure you use a realistic 18" of vacume rather that the 28" of vacume. That way you'll get a better real world comparison.
