Quick question: Olds J2 intake

[briggs&strattonChev]

hey. Will a J2 intake manifold bolt up to a 394 olds? Any help is appreciated.........................Briggs

[55olds88]

From memory if its a 57 371 thats about all it fits, I think the block was raised for the 394..... I could be wrong.

[briggs&strattonChev]

im almost positive its the same J2 manifold 57-58, but yeah, they were on 371's

[BigJim394]

Some manufacturer made machined wedge plates / spacers that allowed you to use the 371 specific manifolds on the later 394s. Pretty hard to find these days, though I have seen them on ebay and at swaps and one HAMBer posted a pic of oa set he owned, one time.

[Blownolds]

The only cast iron Olds 3x2's for the early Rocket engines were the '57-8 371 J2 intakes. If this is the intake you are talking about, it will not fit the '59-60 371's or the '59-64 394's, which all had a taller deck and take a much wider intake.

I HAVE seen, on two occassions, iron J-2 intakes on 324 engines. One was a running '55 engine with the '55 #8 heads, one was a crusty old '56 engine with the '56 #10 heads. I don't know what has to be done to make it fit the earlier engines nicely, but I suspect:

--you'd probably have to mill the mating surfaces (I have heard there is a slight angle difference)
--you would not really want to run a J-2 intake on pre-56 heads if you could help it due to the large intake ports going into a smaller head port--- BAD FLOW RESULTS-- Just make sure the head ports are at least as big as the intake ports and not grossly misaligned.


To put a 3x2 on a 394, you will have to use an Offenhauser or Edelbrock aluminum intake. Or spacer plates for an earlier intake (but why?)