302 head question

-
gipperco

gipperco

Well-Known Member
Joined
Mar 13, 2007
Messages
252
Reaction score
0
Location
Turner, Oregon
Ok everyone I am totally confused. Today we started cleaning things up and while my wife was cleaning the heads of her 318 she asked me what does this J by the last spark plug hole mean? I went over and looked and sure enough there is a J there. I thought that J castings stopped in the mid 70's but these heads are cast with 302 as the last 3 on them. weren't 302's in the early mid 80's ??????? I don't have exact measurement tools but I measured the intake valve with a tape measure and they are only about 1-3/4". What the heck do we actualy have here??????

Dazed and confused. HELP!!!!!!!!!
 
Sound's like you have 85-90 302 heads, small heart shaped chambers and large pushrod hole.
 
so the J stamping means nothing then like it did in the early 70's versions is that what I am understanding? it is the 302 casting number that is the important then.
 
The early letter castings have very big letters raised up by the spark plug holes. In the top picture, you can see the "J". This is a '72 head. The next shot ( bottom) is a 318 with the number "5". This is a '79 head.

100_0805.JPG


100_0806.JPG
 
To me I only go by casting number, the letter, like "J" "U" "O" "X" etc mean nothing to me.


Chuck
 
I agree with you 340 mopar, as you could have the same casting # with different letters.
 
or different casting numbers with the same letter. "J"s can be 915's or 587's and now it sounds like 302's


Chuck
 
there is also a number 4 cast on it too just like your number 5 and the J is the same in size and location. So from what everyone is saying, IF I understand it correctly, the casting number is definetly 302 so that is what I must have. I tape measured the intake valve, I know not very accurate but the best I can do right now, it is right at 1-3/4".

Thank you.
 
what is the stock ehaust size on 360 heads. beacuse i was told that i should have that done to my 302's.
 
So 1.60's is what I have been told to use. Is that enough or should I go with the bigger ones? Will .10 or .125 really make that big enough difference for the expense? I guess I am asking is the bang worth the buck here for that change?
 
If the valves are close in price, and they probably are, the bigger valve would help in the exhaust poret since they flow poorly in stock form. The extra size will help, but it is a very small amount.
At this point, any help is a step in the right dircetion.
Watch that you do not get Magnum valves.
 
You must log in or register to reply here.
-

Back
Top