michformulaS
Well-Known Member
I mentioned tonight that I am finally getting my 416 with ported X heads built. Currently I have a 318 with "O" heads in my car....What is an "O" head?
Same as a X,J,U, etc....A 340/360 head. Valve size of an X is a 2.02-1.60 and sometimes the J as well I'm told though I never seen one stock this way. All others should be a 1.88 intake and 1.60 exhaust though nothing in the MoPar world is in stone.
They all flow about the same reguardless of letter except where the valve is bigger.
Thanks....I figured they weren't anything all that special. I will keep them for a D100 project I want to start next spring
...The only difference is your X head will have an X by the plug hole and the O head will have an O by the plug hole.
'O', BTW, some very early '68 "X" heads (2531894) weren't even cast with an 'X', but to alleviate assembly line confusion, Chrysler later had them tooled to be cast with an 'X'.
Mark.
Well, that's part of the difference. lol
The 'O' heads, as with all small block heads beginning with the 3418915 (J, O, U, and Z) casting on, have wider lower head bolt bosses.
Supposedly to help with head gasket sealing.
'O', BTW, some very early '68 "X" heads (2531894) weren't even cast with an 'X', but to alleviate assembly line confusion, Chrysler later had them tooled to be cast with an 'X'.
Mark.
Well, that's part of the difference. lol
The 'O' heads, as with all small block heads beginning with the 3418915 (J, O, U, and Z) casting on, have wider lower head bolt bosses.
Supposedly to help with head gasket sealing.
'O', BTW, some very early '68 "X" heads (2531894) weren't even cast with an 'X', but to alleviate assembly line confusion, Chrysler later had them tooled to be cast with an 'X'.
Mark.
My very late built 70 340 Dart came with a set of 2.02 J heads on it.
Dang it! Got sucked in to the old thread dimension again!Pretty old thread. Thanks for the info. Kim