Has anyone had problems with the Moroso mounts not lining up? I've double checked the part numbers (generic SBC engine side and 3rd gen specific frame side). The bodyside pads are labeled driver's and passenger side and I can see the difference, I have them on the correct sides. The engine side mounts appear to be the same and they do not have labels. with everything loose (mounts/pads on both sides, the k-member bolts just snugged, trans mount lose...) and all the prying, coxing, pulling, and pushing with a jack I could come up with this is the closest I've gotten it, the driver's side is too far forward by about 1/4" or so, and the passenger side is too far up by about the same. If I try to coax it halfway in between or to get the weight off the pads to try to get the bolts in the holes they move farther off.

driver's side, about 1/4" too far forward

passenger's side, about 1/4" too high

 

I had the very same problems to yours with the exact same parts set up. Only way I could do it was to leave everything loose, support the engine with the hoist, even loosen or completely disconnect trans mount and pry, manipulate, hammer it all together. After all that I ended up with a ridiculous harmonic that would cause the body of the car to have a pulsating vibration at some combinations of road speed and engine RPM. At WOT I swear the vibrations through the body of the car were louder than the engine itself. I ditched the Moroso mounts in favor of Holley clamshells and poly mounts with the UMI fbody block mounts. The fit was 1000x's better. Haven't been home long enough to drive it yet to get a feel for the improvement but unless this car is pure race car the solid mounts are pretty awful for street driving. I read your previous post after responding here and I'd have to say my experience was exactly the opposite of what others were saying. The rowdier the engine the worse the road manners become with solid. With the stockish 305 and solid mounts the car was quite bearable but when I put the 383 in it was a different beast altogether. Body rattles were more pronounced as was engine vibration though the chassis. If these poly insulators fail me then I'll go to rubber but I will not go back to the solid mounts.

 

Engine side mounts are different with different parts numbers.
that said, leave everything loose. Those mounts don't fit well on anything

 

After contacting Ramey at UMI and he pointed out that there's been another person on here that had all sorts of problems with Moroso solid mounts and a UMI K, and after searching it appears that people in general have problems with the Moroso mounts. I believe it's the mounts. He also mentioned that they're going to be making their own in a few months that should fit much better.

I tried removing and swapping the engine side mounts. No dice, they are literally identical (though mounted on the engine they look different, one looked like the "ears" were further forward then the other).

In the end bruit force and ignorance won- I loosened everything, wiggled/shook it as much as I could to get it to move to the right place, marked what direction they are off and then slotted the mounting holes for both sides, cut them and bolted it together so both sides dropped in easily. Done. I shot some video and a few still pics that I'll post in a few days.