91 stock ls 4-1 jdm header swap?? Anyone done it and can give tips?

I’m trying put the 4-1 header on a stock 91 integra. I know I have to notch the cross member and reweld it. The thing Im conserned with is will it fit with my oil pan and there is a support bar running right on the other side of the oil pan from the cross member just passed the axel. Will it fit? Any tips?


I think it takes time for people to respond or maybe not many of us has the jdm ITR header.

U need to try to search and come back and explain if u havent found any in searching rather then making this when u already made one and it ended with no luck


Best place u can try is honda-tech or nonvtec.com
I just went to honda-tech and type in “itr header on ls” and it popped up alot.

Also to answer a few things. If u plan on using that JDM itr you would have to use a 2.5in CAT coz the collector is bigger and the header/downpipe is longer i believe. Now if it was a 94+ ls its a better fitment.

I believe as far as fitment goes it should do the trick once u notch enough room for the front to clear the crossmember and the support bar under the oilpan and a new CAT with 2.5 flanges. I havent really done one so i dont know if it clears the oilpan or if u need aftermarket oilpan (slim) version if it exist, but this is from info i read so anything would work just have to fabricate or modify it to work/fit.


thanks man i tried quite a few different seaches on here and honda tech but it never brought up anything that would help me…i have been trying to have paitience… but i made a thread last week and all i got was 2 people comment.i just figure with the itr header bein common someone would have done it by now and could help me out a lil…

I have the ITR header on my rebuilt LS block. However, I opted to use the aftermarket IM Front Crossmember which makes the use of the “support bar” impossible. (I’m assuming the support bar you are talking about is the one that connects to the middle of the stock front crossmember.) My oil pan does not get in the way with this setup.

I’ve heard that GSRs don’t even come with the support bar, so I assume its not a critical part incase it gets in the way of the header.

hope that helps.

Yea the support bar (center Beam) can be removed but if u want ridgity i would keep it there.
I used to have the lower tie bar for the front and when i used it it sorta help but not much then i took it off
for over 8 months though i still had the clamp/bolt piece on the car. After that I finally got to it again and when i got back to installing it the thing wont line up so i had to adjust it more. That tells me my car shifted or moved a bit NOT GOOD.

glad i can help.

thanks a lot

what header couldi get that would fit with it with out spending a bunch of cash?

If u are planning to stay non-vtec and plan to stay around 7.5rpm range get a 4-2-1 for better low to midrange. For good low end to midrange pull.

If u going vtec get 4-1 so u can make good use of the mid to high end mainly.

Someone lead him to a shop/site for some cheap deals?