Got a big question for all you mopar nuts,

what years from 91-95 were the output ports on the exhaust manifolds bigger?

I was sending my stock manifolds out to get porcelain coated for my project and they sent them back cuz the passenger side was cracked

i went to my truck salvage yard which has quite a few magnums lying around and the owner told me to take them off of whatever engine I could find so. I found a good set that had EGR

got them coated a To my surprise the output ports were way bigger! My old ones were 1 7/8 , the new ones I got are 2 1/8 inch!!!

i have read all different reasons;
only installed on Jeep Grand Cherokees,
early versions from 1991 like first 6 months of production

unfortunately i didn’t look at the side of the block I got them off of to see what year the engine was made

i was a dealer tech for 20 years from 87 to 08 and never noticed the difference! Lol

so I’m asking the real experts out there, what vehicle and what years were the manifold output ports bigger??

viperdave

 

Anybody?

I can’t be the only guy that has run across these bigger manifolds

heyyou, have you heard of these??

 

I have never heard of that. No mention of it anywhere either

 

Well it’s a real thing,
had to re make the exhaust, had to do it anyway cuz I went from single to dual like the 1 ton v8 trucks had with dual cats in 1995 I think the v10s had dual also and the shop had to remake the head pipes to fit

i know the original engine was a magnum out of a truck 1995 and the engine I took the manifolds off of was a magnum, both had EGR. Which means it was pre 1996 OBD 1

i read on another site that they were early manifolds from 1991 first 6months of production but then another poster said they were only on early grand Cherokees

as I said, old ones were 17/8 inch diameter, replacements are 2 1/8 inch. Big difference!!

if anybody has a few of these lying around check and see how big the output is

i know chrysler built some funky stuff for the international market, they made the ram charger From 1998 to 2001 but only in Mexico Seen one, only was made in 2wd but it was cool looking full size BR truck SUV!! XJ cherokees stopped in 1991 but were still made in China up to 2005 and had updated front grill

viperdave

 

“The stock manifolds have 1-7/8" outlets while the jeep ones have 2-1/8" outlets. I should see a benifit. My other choice was a set of hi-po 340 manifolds, but they are running in the 200-400 range while I picked up the jeep ones for $30....I don't want headers on this car.”

That was from a site called ramcharger central


“the 92/3 magnum truck ex manifolds have a much larger outlet than the later ones. iirc 1&7/8 on the later ones & over 2" on the earlier ones.”


That at one was from moparparts.com


there was one flow test where a guy said that the bigger manifolds were actualy as good as headers up to 4000 rpm, then the headers outshined the stock manifolds. I can’t remember what site it was on


there is obviously a difference but nobody can actually quote me production dates


viperdave

 

Oh I'm not saying there isn't, I'm just saying to my knowledge no one knows the answer to your question

 

The only thing that makes sense to me is, late 93-early 94 they made the output smaller to keep the exhaust pressure up, keep it hot and make the cats work better, manifold gets way too hot and warps and breaks the studs or the manifold cracks.

Honestly I have never seen a 93 or 92 manifold crack or studs break, it was always the later BR trucks

which is typical for Chrysler they have something that works great and they try to make it better and screw it up .or they go through years fixing and perfecting a car line and when they make it perfect, it gets cancelled and they start all over again !!!! Lol


viperdave

 

There's a article in the FAQ section of the 1st gen Dakota section that has a copy of a 5 part article from Mopar Action tech editor Richard Ehrenberg swapping a 360 magnum into a '96 v6 auto dak.

There's a complete write-up including pictures of the 'build'. The exhaust manifolds from a 1992/93 magnum measure 2.135" @ the outlet
'94 up measure only 1.875". Hope this helps--& that I copied the right url so you can verify this for yourself. https://dodgeforum.com/forum/1st-gen...ak-5-9-swap-pi Good luck.

 

Awesome!!! Thanks!!