I'm finally getting back into this one. I was making a new transmission crossmember, and getting ready to set up and install the full dual exhaust system when I noticed a few issues with the engine mounts and engine placement. Further investigation revealed even more issues.

A note about this car. The LS1 swap was done a year or two ago by a shop that does really excellent custom interior work. Every thing I look at, it shows that the guy who did it is really good at custom interior work. This engine was installed by someone who was totally awesome!!! at custom interior work.

The engine was installed using a kit from "Butch's Cool Stuff." The kit can be seen here: https://butchscoolstuff.com/42-53-pl...nt-kit-2192cp/ Our car has an older version of that kit with a crossmemeber that was set up for a single exhaust pipe on each side of the car. We're going with a dual exhaust with both pipes on the passenger side. I'm making a new crossmember for the rear transmission mount/support.

Issues.

• When removing the current "Butch's Cool Stuff" transmission crossmember, I noticed that the back of the transmission (and the entire engine/transmission assembly) is tilted in the car. The passenger side is lower than the driver's side. This is not good and needs to be corrected.
• The frame mount on the passenger side of the car was mounted further rearward than the instructions for the mount kit specified. This drawing is from the instruction sheet. The black is the original instructions. I've indicated in red approximately where the passenger side frame piece is welded on the frame.
  
  
• That drawing also specifies that the front edges of the frame pieces should be level with the top of the frame rails, and the rear should be 7/16 below the top of the frame rails. Ours are mounted with both the front and back edges about 1/4" below the top of the frame rails, parallel to the top surface of the frame rails.
• The kit includes an option to offset the engine 1" toward the passenger side to clear the stock steering. Ours has a rack and pinion conversion, so it shouldn't need the offset, and should be fine with the engine centered. However, some Bubba (could've been the shop that did the engine swap, or it could've been the guy who tried to make the AC work who might've been the first to try to install an AC compressor) used the offset parts to offset the engine 1" toward the driver's side in an attempt to make more room (still not enough room) for the AC Compressor in the stock, low mounted position.
• The car had some center collector shorty headers (possibly Sanderson "block huggers"). Because of the relocation of the passenger side mount, the header collector was actually touching the rubber cushion of the mount there, and it burned away part of the rubber (maybe 1/4 of the total rubber) and turned the entire rear half of that rubber mount cushion to charcoal. The header hitting the mount like that could be a contributor to the clunking and knocking noise when the car is driven.
• Someone tried to cut the frame to clear the AC compressor, gave up, and cut and ground a bunch of material from the AC compressor itself. There's no lower front mounting bolt installed, and the post for that mounting bolt is half gone. It looks like they may have also ground on the compressor housing itself. I'm pretty sure the compressor is actually hitting the frame while driving.
• On the driver's side, the header has less than 1/8" clearance to the steering rack where the pinion shaft comes out of the rack housing. I'm pretty sure it's also hitting when driving, contributing additional clunks and bumps to the mix.
• There's almost no clearance between the header primary pipes and the fender on the driver's side. There was also a rubber power steering hose against the front pipe. Miraculously, it isn't leaking, but I think it's melted and collapsed and I think that's a major contributor to the lack of power steering assist. Someone cracked a couple of the spark plug insulators putting the header in on the driver's side. I had to pull the plugs out to get clearance to get the thing out. As an added bonus, the front most bolt holding the driver's side header on was a 7/16" diameter grade 8 bolt. Someone must've stripped the hole and instead of using a heli-coil or time-sert, they drilled it out and tapped it for a much larger SAE grade 8 bolt in that position. That means I'll probably have to drill out any new header I install there, and also have to cut on the gasket to clear the larger bolt. Oh, joy!
• The rubber pieces on both mounts seem to be installled upside down, in a way that lowers the engine even further and reduces the thickness of the cushion. Either that, or someone cut the cushions down for some reason. There is lots of clearance above the engine, so lowering it this far isn't a major priority, and raising it by the thickness of the cushions will not be an issue at all, it'll probably be a good thing.

Things that need fixing.

• The AC must be functional on this car. It's essential to the car's mission. It's not working now, and I'm pretty sure the compressor has been destroyed in an attempt to fit it inside the frame rails. The warranty has definitely been ground off entirely.
• The noises, clunks and banging issues need to be resolved.
• We have worn universal joints on the the drive shaft right now, and some shakes/vibrations that could be drive line related. With the front of the engine a full inch to the left and the rear of the transmission centered on the car, that misalignment certainly isn't helping the situation and could be contributing to this.

I'm looking for some advice here.

I think I'll need to relocate the AC compressor high on the passenger side. There's a Vintage Air unit inside, under the dash. And we may need to do something to put a second unit (or move this unit) to the rear, either under the front seat or in the front of the trunk. Again, AC is critical to the mission of this vehicle, and rear seat passenger comfort is far more important than front seat/driver comfort. I see a number of kits for to relocate the compressor. Some on different LS specific sites like https://lsxinnovations.com/product/l...c-bracket-kit/ and https://lsbrackets.com/2010-13-camar...er-ac-bracket/, and others on Amazon like I think with our Vintage Air setup, the Sanden compressor would be preferred. Any experience with any of these kits would be welcome here.

I'm going to need to remove the extension piece for the offset from the passenger side mount on the engine. Actually, I'll be calling "Butch's Cool Stuff" Monday, because the person who set this up cut that piece way too close to the hole when they installed the extender piece, and it's cracked around the outer part of the hole we'll be using, so a new bracket for the passenger side is likely needed at this point.

On the passenger side, we'll need a different header. We ordered (and received yesterday) these https://www.summitracing.com/parts/sum-670250 The passenger side header from that seems to fit well and resolve the issue with clearance to the engine mount without causing any other issues. The driver's side on that set hits the steering shaft with the engine pushed to the driver's side like it is. Even with the engine centered, it looks like clearance to the steering shaft will be a problem. I may have to retain the center collector header on the driver's side and run mismatched headers if I can't find a set that fits properly on both sides. I'm open to better suggestions here. Has anybody used the Patriot Exhaust "tight tuck" headers (their number 8086)? Those look like they might work. Here's a link to them on Summit's site. https://www.summitracing.com/parts/pte-h8086/

Any advice, experiences, or comments are welcome here.

 

Following up, these are my biggest questions about the mount situation:

1. With these mounts https://www.speedwaymotors.com/Unive...-Kit,1199.html exactly how critical is it that the lower pad (welded to the frame) be parallel to the upper pad (attached to the engine block)? I really don't want to cut the pieces off the frame and reweld them.
2. Can I use a metal shim between one of the pads and the rubber to raise the passenger side and level the engine?
3. And if the answer to #1 is that the surfaces really do need to be parallel, can I use wedge shaped shims to accomplish that?

 

If the mounts incorporate a through bolt that acts as a pivot, then the chassis and engine mounting surfaces need not be parallel.
However, if the cushion itself handles any angular changes then the mount needs to be affixed so there is no distortion of the cushion at rest

 

You've pretty much confirmed what I was thinking. These are the "rubber pillow" type mounts. Here's a couple pix. One from the "Butch's Cool Stuff" pix showing the bracketry used.




And here's the replacement rubber pads and bolts from SpeedWay Motors.



So I'll need those to be between parallel surfaces. I either need to correct the alignment of the frame pieces or I need a wedge shaped shim on one side or the other so the surfaces against the mounts are parallel.