Quote:

1971 j heads from a 340 thier not here so I'm not sure. Just looked them up 1.78 in. 1.50 ex.



Should be 1.88 in and 1.60 ex at least if they are J head.

I thought 71 340 J's are 202 in and 1.60 ex but may have switched to smaller 1.88 intake late in production??? Don't know about that.