I am helping a friend with the mentioned swap. Sat the car down on the engine last night and the passenger side header (Hawks) is touching the frame rail pretty hard, I mean its right on it. And there is now way the number 8 coil is going to clear the AC/Air box. We used hooker LS swap brackets and reused the thirdgen motor mounts but installed new prothane guts in them.

I was wondering if anyone has shimmed down the K member to get some more room on the coil, or what everyone is doing there. As far as the header I have no idea what we are going to do there. I didn't get any pictures because it was late last night when we sat it down on there.

 

Some have trimmed the hvac box, some have relocated the coil.
I remember reading a build that had the same frame rail/header problem, but I can remember the solution, nor can i find the thread.

 

Yeah, I have been searching too but cant find anything. May have to call Hawks Monday to see if they can give some insight. Where are guys putting the coil?

 

Some guys are Using the truck coils/brackets, and rotating the rear passenger coil a bit. Jazzdadss's build thread shows how I believe. Also, if planning on removing A/C, a AC delete eater box provides plenty of clearance for the coils.

Another hawks header fitment issue, where the collector hits the frame.... What a surprise!!(sarcastic). Hopefully you have better results speaking with hawks, they were completely un-concerned when I had the same issue, just told me to expect that with aftermarket parts. Acceptable on 100 dollar Chinese headers, not 700-1100 dollar pieces. I was able to Insert a pipe that fit tight into the collector(so it didnt oblong the collector) and tweaked it until it did not hit anymore. Clearance is very tight and I have to use band clamps now, they don't seal perfect, but the exhaust leak is not audible. Others have had the collector cut off, re-angled, and welded on in a slightly different orientation to gain the clearance needed. Some have even had 3 bolt or Vband collectors added for better sealing. A handful of folks have gotten lucky and headers fit great.

Search "hawks header fitment issue" here in the ltx/lsx swap forum, and there's two solutions with photos so far.

 

Ok thanks I will see what I can dig up.

 

If you want a cost-effective method for the HVAC to coil clearance issue, just grab some truck coils and brackets and throw them on the car, should clear just fine.

It's weird though, my dad's '89 IROC-Z that had an LS1 swap with A/C had a factory HVAC box and 1998 Fbody coils and brackets and he didn't have any clearance issues.

 

I trimmed a bit off hvac box & coil bracket no issues but it is a tight fit

 

The 98's are different right? They pretty much bolted the coils right to the valve cover and were up a little higher, they changed in 99 which is what we are dealing with. The bad thing is he just bought these coils. So will be selling them and trying to find some truck coils. Any certain year engine size to get them off of? I am wondering if our swap is tighter than most because of our motor mount setup.

I found the Hawks header fitment threads, that sucks. Either bend them or cut them and re-weld. That's great.

 

I have heard the "melco" truck coils are slightly hotter.

 

97-98 LS1s and LSA/LS9's mounted directly to the valve covers

Take a coil off the bracket and bolt it directly to the valve cover. Only one hole will reach. If that works, then just trim the bracket down and mount the last coil with one bolt

Truck coils came in many flavors. The round ones with the external heat sink are favorites because they are slightly more powerful than previous versions. Be aware that when switching to truck coils, the drivers side fuel rail feed will not clear and needs to be bent upwards. They also require longer plug wires

Personally, I wouldnt modify the headers. Id build better mounts shifting the engine to the drivers side

 

Will try mounting it right to the cover, how do you suggest modding the motor mounts to moove the engine over?

 

Wouldn't shifting the driveline over to one side make driveshaft alignment/vibrations a possible worry?

 

I dont think so, I now the old Ford truck I pulled a nine inch out of, the 9 inch sat 4" to one side vs. the trans centerline.

 

Not really, he's not building a pro-mod. Anyways, stock the driveline is almost 2" to the pass side and a few degrees turned which meets up with a centered rear axle. Nice going GM...

Do the best you can. I found it was easier to build new mounts from scratch

 

Just had no clue how touchy that stuff was, or wasn't. Had no clue the driveline was mis-aligned from center from factory.

 

Me either until I read a few shaker hood build threads