I do not believe The header from a 4.2 258 will not fit the 4.0 motor. The intake and exhaust ports on a 258 are all even with each other. On a 4.0 the intake and exhaust are staggered. I think you will run into fitment issues if you tried to swap.
Nope, different designed head. The intakes will swap with a little tweak, but not the exhaust.
86/00 CJ7 Laredo, 33x9.5 BFG AT's, 'glass nose to tail in '00, 'New' frame,wires and plumbing in '09. Carter BBD Carbed 4.0 HO in '10.
89 YJ Renegade. BBD Carbed 4.0 HO. Locked front and rear with 33x9.5 BFG AT's
Some Canadian Bush Jeep Runs and Build Photos: http://mikeromainjeeptrips.shutterfly.com (10 new albums added Sept 16/10)
4.2l CJ headers will fit, However there may be some fitment issues with intake manifold thickness(spacers), O2 bungs(easy to add), EGR valves(eliminate), carb heat risers(eliminate) , pulse air systems(eliminate), and auto trans linkage clearance issues. If you have tough visual emissions issues they may not be for you.
It Wouldn't Be A Project If Everything Worked Right.
Borla makes one and they are based in California. Just make sure that the EO number that is stamped on the header matches your year. I installed mine and then the smog station said it was the wrong EO for my year so I had to have Borla send me the correct EO and then I had to tack weld it on after installing. Pain in the rear.
yea, I actually found those previously and forgot about them... I was surprised that hooker and hedman didnt have anything... and a few others... not sure why...
and yea, the bung can be added but it will get shot down by the visual inspection... as will the pulse air system... Ive heard they don't care about the hot air riser and carb choke isnt as much of an issue, (as we are in sunny so california... )