you could try sliding the K member towards the passenger side to gain clearance.
this could cause V cover clearance problems on passenger side.

sounds as though you are being backed into a corner

With the R valve cover and shim removed does the header still hit? and if so, by how much? how much lift on the on the L side is required to gain adequate clearance?
While in that lifted position how level is the carb flange ?

Lot's of questions but trying to establish what is the path of least resistance to correct the issues

The steering box hits the header with or with the shim. I need the engine to be lifted atleast 3/4" in order to not have the header hit the steering box, however, by doing this, the stud on the engine mount isn't even close to being long enough to fit through the bracket that bolts to the engine and although I haven't tested it yet, I highly doubt that I will have any hood clearance to shut the hood. Surprisingly, with the engine mount having the big gap on the drivers side, the engine sits almost perfectly level. It also sits very high, to the point that the fan blade is almost above the radiator. It can't go down any further though because of the steering box.

What transmission and cross member? You might be to low and that incorrect radiator may be an illusion.

Stock hemi 4 speed and original transmission crossmember.

Boy have you ever had the fitment issues with this car. Just seems odd that most people easily overcome fitment issues. Any idea if the car has been wrecked?

No accidents. Car sat since 1981 before I got it. I had to slightly clearance the power steering box that was originally in the car for the headers to fit with the original small block k member with the Schumacher conversion mounts. I thought for sure once I had the hemi k member conversion done by al debevec and the manual steering box, which is half the size installed, all of my issues would be fixed. They're even worse now. Everyone praises his work and they don't have any issues. I called him about the issues and he said he builds them on a jig and actually tests the fit with TTI headers. I don't know if it's a bad set of mounts or headers at this point. With a hemi and headers, I can understand a slight bit of rubbing somewhere or maybe a small ding needed in a header tube, but even with a manual box, the engine can't even physically be installed in the car.

Al did my wedge to hemi conversion for my 69 Charger. I have the TTI 2 1/8 headers. First was the valve cover right side. Got a new clearanced one from Indy. Then the left header was hitting the pitman arm. TTI said it was the K-Frame. It measured perfect from what they have listed for locating from TTI. I was lucky and found a cherry original Hemi K and stuck that in. Guess what same thing. Al's work was spot on. TTI took the left side back and sad wow we made a mistake. So I get it back and pitman is fine but now its hitting the power gear box. TTI just said send it back. I made a hardwood mold and massaged the header in my press along with grinding the gear box. I must of dropped the K out 3 times before I was able to get about 1/8 to 3/16 clearance. I was not sending them back again. The guy that bought Al's K from me said it worked perfect for him. Al will tell you straight out he hates headers as every one is different. Just my 2 cents

Take a look at the distributor height to R F'well that thing is way too high in the front IMO

Thats why I asked about the trans and crossmember. If it was low back there it would raise it in the front. He claims its all ok back there. He is already hitting the gear box so lower is not an option. There is something wrong somewhere.

I trust Al's work 100%. I'm thrilled with the quality of it. When I received the k member from him, the drivers side insulator was broken right in half in shipping. I guess I'm lucky that it broke then, because I called him and he said he got a bad shipment of mounts and others had the same issue after they were already installed and they broke so I sent them back and got a refund from him. He didn't want to send another set because they were all having issues.. He said they were just stock style hemi mounts and any other stock style would work. I ended up ordering the polyurethane mounts from Mancini which look like the Schumacher poly loc style and are maybe just removed. Right out of the box, the drivers side didn't fit right and would bottom out on the mounting pad on the k member. There was too much extra metal on the insulator bracket so I ground it down so that it would sit flush on the k member. However, whenever I set the weight of the engine down onto the drivers side, it shifts the top part of the drivers side mount up about a 1/2" or so as seen in the pictures in the beginning of the thread. Now with the box installed, it's about a 3/4" gap and the bolt that goes through the k member won't even line up.

100%. Sometimes walking away for a few days or another pair of eyes will reveal the issue. Myself, I would come back to the valve cover issue at a later time and get the motor in where it is supposed to be.
I had a Magnum force FE with a 472 dome by another shop and it was a flippin mess. Of course we were the only ones with this problem . Original owner 69 Charger never been wrecked. Took a lot of hours to get things sorted out.

Another though just occurred With the motor in place as it is, what is the oil pan to crossmember clearance ?
Remove the L header and R valve cover set it back in place and measure again. While it won't resolve the issue it may give a clue.
i will also mention we have had to move header tubes or dimple them more than once.

I do have a long story on Hooker header side exhaust that I'll save for another time. I will say they did compensate me once they were caught with their pants down. Another case of "You're the only one with the problem" REALLY??? 💩💩💩💩

i commented in another thread : "as the buy-outs continue, the quality goes down" [or something like that]
as was mentioned above about a shipment of bad mounts.........
as to the OP, there is a diagram in either the engine book or the chassis book published by DC and MP, that gives engine location referenced from the crank centerline.
if it were me, i would get the engine set in that position, then see what is amiss with the mounts.
maybe the 318 K mount is off a tad, allowing the 318 to fit ok enough, but causing issues with the hemi and the conversion mounts.

I have plenty of oil pan clearance all around. I'm not sure what I could check with the transmission crossmember. It’s the cross member that was in the car when I got it and I installed a brand new mount, so it's not worn out or sagging. At this point, I can even live with the valve cover hitting the inner fender for now, I just need to get the engine sitting correctly on the drivers side so that I can bolt it in. Denting the header tube in isn't an option as I would have to almost dent it in almost 50% shut to get the clearance. The front bolt is the first part that hits on the top of the steering box but even if I was to grind some material off the box, it would help but it still wouldn't be enough to allow the engine to drop all the way down. I don't gave any other mounts to try for comparison either. Even with the same k member before the conversion and the Schumacher conversion mounts, it always sat very high in the engine bay.

It sat like this with both the k member pre conversion and Schumacher mounts and with the k member after the hemi conversion and original style mounts

What is the distance from the center of the crank to the top of the k-frame?

It's hard to get an exact measurement, but roughly 4 1/2" From the center of the crank to the top part of the crossmember directly underneath the crank.

That means your engine is sitting to low according to TTI. Which makes no sense. A 440 wedge or hemi should sit at the same height. You could lay a 2 x 4 across the fenders and measure down to the ID boss on the block. Then hopefully another member could measure his for a comparison. Also what manual gear box are you using? Might all be in the header.

Interesting, I wonder where they get the measurements from? I'd have to add a 3/4" shim under each mount. It would definitely fix my steering box issues, but I wouldn't be able to shut the hood and there wouldn't be enough of a stud on the insulator sticking through the bracket to bolt it down.

It's a pst manual box.