J head question

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ep41

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I'm looking at a set of J heads later today that are supposed to have the 2.02 intake. The casting numbers are 3418915-G and the other is H. He says 360 is also stamped on them. He sent pics, but I can't see the 360, just the casting #'s. I have tried to look the #'s up and have found a lot of conflicting info. I can only think to bring a micrometer and measure when I go, but would really like to avoid a 1.5 hour drive down there if I can verify they are not 2.02. Any help would be appreciated.
 
there is no way to verfy what valve is in them unless they are measured..

being that the heads are almost 40 yrs old...the 1.88 could have been replaced with 2.02..
 
The early 360 head had the 2.02 intake, The later had the smaller 1.88. Do you have the casting date or can he measure the intake valve size for you?
 
He says they are early 70's. I asked him to measure in an email this morning, no reply yet.
 
I would rather have a 915 "j" with the smaller 1.88, this way your assured the valve will be up high when you install your new 2.02 valve. if its a stock 2.02 head thats had several V/J's the valve will be sunk low into the head = poor low lift flow. Just my two cents... Also you would have to look at the cast date code on the head my j's 2.02 are like 3600 = 360=360th day. 0= 70 if you see a 1201 or something like that would be 120th day of 71 so it would be for a very late 71 and 72 car with a 1.88 valve.
 
if you could get a pic of the chamber you can tell just by looking at the gap betewwn the exaust valve and intake valve the 2.02-1.60 valves look like they almost touch and the smaller valves have a gap here is a pic of my 915 x heads before i put them on my engine you can see how close the valves are

scan0006.jpg
 
X heads never had the 915 casting. The last 3 were 894. Look at your picture and you can see the casting #. The 915 "J" heads came both ways. 1.88 and 2.02. The 360 casting on the head doesn't mean that they are 360 heads since the 360 engine came out in 73 for the cars. It's just a casting number, not an engine designation.

Ken
 
He sent me a pic of the chamber and there is a gap between the valves. Does this definitely mean they are 1.88?
 
physixx said:
X heads never had the 915 casting. The last 3 were 894. Look at your picture and you can see the casting #. The 915 "J" heads came both ways. 1.88 and 2.02. The 360 casting on the head doesn't mean that they are 360 heads since the 360 engine came out in 73 for the cars. It's just a casting number, not an engine designation.

Ken
Click to expand...

HUH? I bought a brand new 1971 Fury III with the 360 in it?
 
Thanks guys. You just saved me about 3 hours of driving in evening commute traffic. I think I'll just work on my existing heads on my 360.
 
physixx said:
X heads never had the 915 casting. The last 3 were 894. Look at your picture and you can see the casting #. The 915 "J" heads came both ways. 1.88 and 2.02. The 360 casting on the head doesn't mean that they are 360 heads since the 360 engine came out in 73 for the cars. It's just a casting number, not an engine designation.

Ken
Click to expand...

lol sorry i just had 915 on the brain yes your correct 894 i guess i was still thinking of the j heads
 
I've got 2 360s with 2.20" intakes and "J" heads. One has a C.R. of 10.5:1, and it's a real snorter at all RPMs. However, the other engine has a C.R. of only 8.5:1 because it had to pass smog. That one does quite nicely once the RPMs are built up, but it's kinda doggy off the line. There was a reason the factory put those 1.88" valves on the 360: faster charge flow at low RPMs for better low-RPM performance.
 
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