Sure, you could cut and reweld the headers to fit, but you'd need to make the adjustment up top to get them to angled low enough to miss the hump, then another adjustment at the bottom to get it back where it should be. However, thats also just about as hard as cutting up the firewall.

The main sticking point is right down where the downpipe tunnel curves from the firewall to the underbody- right at that corner. The whole tunnel is nice and smooth, except right in the middle there is a metal protrusion that sticks out into the tunnel area. Since the firewall is double layer- it isn't really feasible to just bang the part in. On mine, my headers down section were sticking above the INNER metal layer of the firewall- so just banging it in would've been impossible.

If you're trying to get it in quick- a PLOG, and custom bent 3" DP would the easier route. Its not particularly difficult, but it is just time consuming if you're trying to make it look halfway decent and not cut a massive gaping hole in the floor just so it fits the first time.

 

well its kinda too late. i already bought the speed daddy headers. i explained it all to the guy doing the install and he feels confident that he can get it to work. so we should know soon.

i was worried about the PLOG as i didnt want the extra expense and it not flow as good as headers. and have yet to see a good rear manifold replacement... ZZP just needs to make a rear power log and have them selfs a nice set of shorty headers

 

Ok engine was finally pulled today and the shop let me get in and do the pounding and cutting to the fire wall for the headers. they say it should be done tomorrow.... so once running i'll have more pics and maybe some video.
Here are pics:





Before:



After:



thanks to bumpin's writeup over on montecarloforum.com i was able to know where to cut and pound the fire wall back. the engine is going in tomorrow so wont know 100% if it all worked yet but it should have been more then enough.

 

Very sweet, can't wait to see it finished

Welcome to the L36 club, and it's time to remove those DOHC badges

 

errr.... i loved those too... they were a hybrid of the olds DOHC badge and the monte badge from the dash board. came out nice. i'll add them to the my wall with the ported intakes i made and are saving

 

hey guys, i am new to the forum, and to monte carlos in general, and its interesting i found this thread when i did. i was about to order some of the headers off of ebay. I saw where the firewall had to be beat up, but was that the only mod needed?? thanks

 

first off welcome to our forum. second, when you get a chance please fill out your signature or put your vehicle info in your profile so we can help you better.

What year Monte Carlo do you have? if you have a newer MC then a 1999 then you will not need to do any modification to your car. if you by chance do have a 95-99 monte carlo then you will need to do this modification.

Just like Bumpin said in the beginning... this is not a mod most will need to do. it is very difficult and a royal PITA. to quote, "pounding doesnt begin to describe it" very true words. i pounded and cut and never did cut space for the o2... so i ended up having to relocate it.

im assuming you already have a 3800 in your car. if you do need to modify the fire wall it will be extremely difficult to do this with the engine in the car. if you wanting more flow, ZZPerformance.com sells their power log. it is a great replacement for the front exhaust manifold and then i would recommend a new down pipe.

 

Don't put on headers. An easier mod is a top swap. You get the extra compression and it adds way more horsepower then headers. Not to mention you can do it by yourself in a weekend.

 

if your going to do a topswap you will probably need headers anyway.

 

I forgot about all of the extra hp that needs to be pushed through those manifolds.