hey guys, i have a 4.2 head and am thinking of using 99 exhaust manifolds. can i do this? i have searched for about 30 minutes now trying different terms and cannot find a thread saying yes or no.
i have a 4.0 head also but need to get it to ndt to check for cracks before i install. i visual'd it and it looked fine but i don't want to install and find something wrong and not have my vehicle to take the kids to practices and such.
also, still no one makes an adapter to put a carb on that 99+ intake manifold? i got that too
I don't feel like working on anything, at this time.
This may or may not help, but in a previous career I spent a lot of time analyzing lots of things. So I tend to look for cause and effect relationships.
I bought my first Jeep about a year ago, an 89 YJ with a 4.2L motor. Had to redo the exhaust system. One of the glitches was a broken manifold stud at the rearmost position. Reading up on here and another forum, the 4.2L motors have a reputation (on the YJs) for either cracking the rear part of the exhaust manifold or shearing that bolt. When I started reassembling with fresh gaskets etc., it became obvious that the manifold hole did not match the stud position closely enough.
I elongated the hole in the exhaust manifold by about .10 inch with a die grinder. I also found one other bolt or stud with questionable alignment near the middle of the head and relieved it slightly. I don't expect to have a repeat of the broken stud problem nor a cracked manifold. New gaskets on both manifolds and all ran well with no leaks.
Why are you trying to put a carb on the 99 intake? You would have to make your own adapter. If you want to keep the carb with the 4.0 head you can use your current intake. I think you might have to grind the mounting flange in a couple spots but it will work.
The 4.0 intake is designed for dry flow with the injectors at the head. It is not suited at all to mounting a carb on. If you want a good flowing carb intake, but one of the aftermarket 4.2 4bbl intakes.