273 Commando pistons are above deck pistons, you're closed chamber heads will interfere. You'll require really thick head gaskets or open chamber heads like the heads that came with that motor originally. 65'
1965 commando's had closed chamber 315 heads and steel shim head gaskets, That's what I read from other posts.
from another post >> 273 4-Barrel Thin Head Gasket {.021" thickness}
Original Part #2463 338 General Information
Near impossible to find a set of Original {.020"} Thin-Steel Head Gaskets {#2463 338} for the 273 4-Barrel.
But, if you dig a little, you can find a set from the 1968 318 {#2806 984}, {.020" thickness} which are designed for the 3.91" Bore.
Or possibly.
1969 Part #2951 259 {.028" thickness}
1970 Part #2946 082 {.028" thickness}
another post >>> The steel shim gasket wasn't just on the 4 barrel 273...they used on the 2bbl as well...big blocks had 'em too. That's what they used back then.
