EARLY HEADS ON A LATE 360

JERSEYJOE

WITH NO OTHER CHANGES WHAT WOULD THE STATIC COMPRESSION RATIO BE IF YOU INSTALL EARLY ( 1970 ) 390 HEADS ON SAY AN 87 360? I'M GUESSING IT WOULD GO UP .5 FROM 8.5 TO 9.0?

AMX69PHATTY

Spreadsheet I made shows 8.48:1 stock with 57.92cc & 9.07:1 with 50.60cc on an otherwise stock 360.

JERSEYJOE

Thank you. are yhere any issues with chamber shape of the 50 cc head and the late model 360 dished piston?

AMX69PHATTY

I'm no expert, but don't believe so, pretty sure AMC kept combustion chambers pretty much the same shape all along, just shallow or deeper.

tufcj

I'm running 291-C heads on the 75 360 in my CJ. Running stock pistons, stock bore. No problems at all, just slightly better compression. Bob tufcj

JERSEYJOE

I HAVE AN 87 J-20 THAT HAS SOME BAD VALVES, LOW MILES. I WAS GOING TO PULL THE HEADS AND PUT A SET OF 70 360 HEADS ON SINCE i HAVE SEVERAL SETS AROUND. MIGHT EVEN THROW IN THE EDELBROCK CAM I HAVE LEFTOVER. TRUCK IS ALMOST RUST FREE

73hornut

JERSEYJOE wrote
I HAVE AN 87 J-20 THAT HAS SOME BAD VALVES, LOW MILES. I WAS GOING TO PULL THE HEADS AND PUT A SET OF 70 360 HEADS ON SINCE i HAVE SEVERAL SETS AROUND. MIGHT EVEN THROW IN THE EDELBROCK CAM I HAVE LEFTOVER. TRUCK IS ALMOST RUST FREE

Should be a good combo, also add crane valve springs and new retainers and keepers.