340 Heads
- Thread starter jefflock
- Start date
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1qwikScamp
Well-Known Member
x heads are 340 heads and the j's are 360 heads
D-mailman
Well-Known Member
The 'J' (915) heads were used on the '70 six-pac engines with different machining and 2.020 intake valves. Also used on the '71 340's with 2.020 intake valves and '72 and '73 340's with the 1.880 intake valves. It might be more accurate to say the 360's used the 340 'J' head with the smaller intake valves. I believe the 'X' (894) heads were used on the '68 and '69 340 engines, and all 340's after that used the 'J' heads as well as the 360's until they were re-cast as '587' ...Some one might want to check me on this, my memory being what it is now (I am older than I have ever been) but I believe this to be correct... Terry.
My '72 340 motor has 'J' heads.
1qwikScamp
Well-Known Member
i thought that the 6 pack 340's had x and z heads on them
1qwikScamp
Well-Known Member
sorry guy i am being a little missleading the j heads are called 360 j's but they came on 340's and 360's alike where as the x's came only on 340s as far as i know
pagilman
Well-Known Member
I believe the J's had the hardened valve seats for unleaded gas.< check on that. they all had 1.88 intake valves except the ones put on the 340's at the end of production. ( excepting the t/a and aar which had J heads but they were cast differently with offset push rods,) :coffee2:
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