CadillacPat
08-03-2005, 02:27 AM
I have run into a 500 (the fourth throw casting number is 1496793) with "493" 120cc heads and flat-top pistons. The
"Caddy Shack" site page, http://www.geocities.com/MotorCity/Pit/9364/guide/Engineid.html
only mentions the '74 472 as the only year 472 having a "true flat-top" piston. I know 472's and 500's have the same rods, and make up for different strokes by changing piston pin locations (472 and 500 pistons are not interchangable). Did the 500 of the year also have flat-tops? Also, since the '75 and '76 engines also used 120cc heads, and with small "eyebrow" reliefs for the valves which resulted in an 8.5:1 CR, wouldn't this combination of using flat-top pistons with these heads result in a higher than advertised 8.5:1 CR? The engine has an HEI distributor, but is apart and was last painted "Chevy Orange". Also, I have two '74 500's, but both are together.
"Caddy Shack" site page, http://www.geocities.com/MotorCity/Pit/9364/guide/Engineid.html
only mentions the '74 472 as the only year 472 having a "true flat-top" piston. I know 472's and 500's have the same rods, and make up for different strokes by changing piston pin locations (472 and 500 pistons are not interchangable). Did the 500 of the year also have flat-tops? Also, since the '75 and '76 engines also used 120cc heads, and with small "eyebrow" reliefs for the valves which resulted in an 8.5:1 CR, wouldn't this combination of using flat-top pistons with these heads result in a higher than advertised 8.5:1 CR? The engine has an HEI distributor, but is apart and was last painted "Chevy Orange". Also, I have two '74 500's, but both are together.