Originally Posted by wreckchick
When I'm cruising in gear but without applying any accelerator, the exhaust is popping. I'm assuming it's back pressure and it makes me want to open it all up a little bit (or a lot a bit, I'm flexible).
I'm putting a new carb on it so I'll have that side of the engine torn down already and it seems to be a perfect time to put in a new manifold. Should I do it? Also, what should I get?
If the popping is happening during deceleration, it's normal & might even sound cool to some folks.
I cant remember if you ever did say you had a 4.2L I6 & what year your jeep is.
These two details would be a big help to me.
The intake manifold on the 4.2L is fine for the MC2100.
when doing the swap, there are a few things on the intake that should remain hooked up.
The intake manifold heater. Needed to keep the air/fuel mix from the carb vaporized, until the manifold warms up. Also it's sender switch.
The CTO switch (or valve) whatever it is, & all the vac lines for it.
The charcoal canister.
The EGR valve.
Now the exhaust manifold (log) can be replaced with a header.
Hedman, & Pacesetter being two companies that make reasonably priced headers for the 4.2L
Both of these companies make a dual outlet header,(6 into 2) in case you are putting duel exhaust on there.
Did I mention, that none of the mods we've been discussing lately, are exactly legal? Nutter, MC2100. Exhaust mods too.
If you don't have Emissions inspections there, you'll probably be OK.
And for the tree-huger in you, it's likely that your engine will run cleaner & more efficiently with those mods, so you won't loose any sleep over it.