318 w j heads?

[moraycen]

Does anyone know if you could get "J" heads on a 70 318. I just bought a old dart (75) with a 70 318 with "J" heads it does not look like someone had put them on.
Thanks Ray

[eric414]

i had a 72 360 out of a wagon with J heads.318 with J heads maybe,thats might be why the older 318 crank of 235hp if i remember right.

[TK]

nope, never. 318's didnt have big port heads untill the 80's. unless the wrong heads were thrown on at the factory, and thats doubtufll.
70 318 heads have the casting number 675

[eric414]

Why made the 318's in 1970 push out 200 and some horsepower VS the late 80's 318's?dont remember the numbers but i do know we didnt get that kind out horsepower out of a 318 until the magnums was born.i have a 1979 volare road runner and it only made 135 horsepower.

[TK]

first off, they had a lil higher compression, my older 318's cc'd at about 59-62cc's. about 72-74, the 973 heads came out, the chambers in them were closer to 65-67cc's.
they were given de-tuned distributers, lean carburators, and they measured the HP at the back of the tranny, instead of the flywheel, and with all the accessories on.
the 318 you are talking about, was 210 HP. that was the truck HD motor, they came in cars, but were more esighned for trucks.
also, food for thought, the 318 ran so good becaus ea balance of compression, port velocity, carb velocity, restrictive exaust manifolds, and rod ratio. the lower compresion and higher flow exayst manifolds messed up this delicate balance chrysler came out with in 67.
the 360 heads, not only lower compression, but lower the performance in mild applications (up to 375-400HP) because of port velocity.

[moraycen]

where will I find the date code on the j head?I dont mean to seem stupid , Im into big blocks!

[rumblefish360]

I don't know how to date them myself, but there made from 70 - 72. They'll have the casting numbers (Last 3) of 915 which also is the 340 T/A head casting number.
J 's mostly came with 1.88 int. valves. Some people swear theres came with 2.02's.