J302 was the part number that Ford assigned to "AR" heads manufactured
by Alan Root. They were developed for Root by Ken Duttweiler and were
the first of the modern Windsor-based aftermarket aluminum heads. Prior
to that, the only aftermarket Windsor heads were the Ford tunnel ports
and the Gurney-Weslakes. I had a set many moon ago. The chambers were
58 cc's out of the box and they nominally used 1.94"/1.6" Chevy valves.
The assembled SVO J302's came with 2.02" intakes. There was no provision
for exhaust heat or EGR. Port volumes were 170 cc's intake and 60 cc's
exhaust. There were dual exhaust header bolt patterns for headers up to
1 3/4" and the valve cover rail was raised for roller rocker clearance.
The were machined for screw-in studs (some of the studs go into the water
jacket so use sealer) and guide plates. They also use solid bronze guides,
grooved for oil seal retention. The intake ports measured 1 1/4" wide by
2 1/16" tall. The exhaust ports measure 1 7/16" wide by 1 5/16 tall and
proved too wide for my Motorsport 1 5/8" stainless steel shorty headers.
Ford and other manufacturers had specific headers for the J302's. The "AR"
specific bolt pattern has the bolts offset, and was adopted by a lot of
head porters who did serious exhaust work on later heads. Fel Pro carries
a header gasket for the J302's. It's p/n 1486 for J302 & K302 (dual bolt
pattern, stock Ford and inline spread bolt Dart & TFS) port Size: 1.40" x
1.40".
Like George said, they are in-line valve Windsor heads, not Cleveland
heads.
Dan Jones
