Answer these questions and I'll give you your approximate mechanical compression ratio.
Engine Bore:
Engine Stroke:
Deck clearance of block: (.035" - .045" is stock I think)
Head gasket compressed thickness: (.038" is normal)
Combustion Chamber CC: 61
Number of valve reliefs per piston:
Going by .038" standard compressed gasket thickness, 61CC heads, 4.03" x 3.25", 2 reliefs:
deck clearance of .00" will give 10.3:1 :edit: fixed!
deck clearance of .01" will give 9.98:1
deck clearance of .02" will give 9.68:1
deck clearance of .03" will give 9.40:1
deck clearance of .04" will give 9.14:1
deck clearance of .05" will give 8.89:1
Whoa... blue thunder... please re-check. Either your way off or my computer is!! Using a -2CC's for the valve reliefs, .010 deck, and the .039 compressed gasket, 61 CC's and 4.00 bore is.... to my computer... only 9.56 !! ?? cool?? vs the 9.8 ?? and with a .000 deck its a whopping 9.8??? not the 11.14 indicated??? Cool??
Whoa... blue thunder... please re-check. Either your way off or my computer is!! Using a -2CC's for the valve reliefs, .010 deck, and the .039 compressed gasket, 61 CC's and 4.00 bore is.... to my computer... only 9.56 !! ?? cool?? vs the 9.8 ?? and with a .000 deck its a whopping 9.8??? not the 11.14 indicated??? Cool??
Oops, I mustve entered 4.3" for the bore instead of 4.03" on the last check, (.000 deck), because that one should be 10.3:1, not 11.14:1 @.000 deck clearance.
I used my own program for calculating ratios. I entered his 4.03" bore and a gasket thickness of .038", though.
Try yours again using his 4.03" bore, not 4.0".