What heads do you have? If you have typical 2 bolt exh. pattern heads, like the truck would have left the factory with, no go, as 7 of the 8 exhaust ports on the CJ exhaust manifolds used the "side by side" exhaust bolt pattern, so only 2 bolts will work on the drivers side, and none on the passenger side. Plus, unless you already have the CJ exh. manifolds, you will likely pay more for the CJ manifolds than a set of good, ceramic coated long tube headers. Why do you want to put exhaust manifolds back on anyway? My 74 F350 cracked 3 exhaust manifolds before I installed a new pair of Hedman headers, the gas mileage and power increase was very much improved with headers, and no more cracks and leaks. I did replace the headers with new ones, after 14 years, only because they look so crusty, but reality, they were still pretty solid.