440 compression

[Garys1969RR]

And due to minor items that increase chamber volumes such as the Piston Ring being down below the top of the Piston a little bit, and sometimes a small taper at the top of the cylinder where it meets the deck, he would probably be closer to 10 to 1 with the 73 CC Chambers

 

[BSB67]

1972 440 - should be rated as 8.2:1, but actual will be slightly different. That would be a piston with a 1.91 compression height, and will be 0.160" in the hole. The very best the head will be is 88 cc, could be 92 cc, assuming that no one has changed anything in that motor in the last 45 years.

 

[Garys1969RR]

He is going with 915 heads, and has measured the piston at .075 below deck.

 

[BSB67]

He is going with 915 heads, and has measured the piston at .075 below deck.

Right on the 915, probably about 80. .75 may, or may not be 0.075. The 1.99" piston, usually in the hole about .085/0.090, would be from a 71, or is a replacement.

 

[ks114]

Thanks for the input. The heads are 915 HP heads.

 

[Garys1969RR]

You will need to cc your heads to know for sure what size the chambers are. You can get a kit from Summit, or make one up yourself. Head cc is the only unknown at this point. Will need an exact size to determine C Ratio

 

[EarlyAuto]

Thanks to everyone on the thread, I feel more confident decking my stageIII heads down to 65cc’s combined with a semi dished Icon .040 piston, .020 gasket and .010 quench to wake my motor up a little.