Anyone know if there is any significant difference between Ford 390 GT exhaust manifolds and 428 CJ exhaust manifolds? Will the 390 GT manifolds work on a CJ head?
The CJ manifolds flow much better than the GT manifolds. Both use the same bolt pattern with the vertical only used on the rear driver side. And there were some 14 bolt CJ "N" heads that were used and found on the 68 Cougar GTE's with the 428CJ engines. As KD said the rest were all 16 bolt pattern. What is the application you want to use the GT mani's on?
I am using them on a 390 with CJ Heads that I am swapping into a 1957 Ford Custom. The GT manifolds that I have fit the car fine. I'm wondering if buying a set of CJ manifolds is worth the cost.
The CJ repops are close to $500. And the originals are a bit more pricey due to the CJ/SCJ restoration costs going thru the roof. But you can find some deals on them every now and then. A nice set of original GT mani's are in the $300 range. Besides being used on the S and X code Stangs and Cougars they were alos stock on the 68 427 GTE Cougars. Personally I'd just use the GT's for now as they fit well without issue and you have them. You can always shop for the CJ's or even a nice header down the road if you want more.
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