here are some notes I made to myself a few months ago, or maybe I wrote them to email to someone else who had asked.
1. Work safe! It is all too easy to crush a finger, a hand, or an arm if something slips. Nothing is worth a permanent disability or missing finger.
2. Raise the car on sturdy jackstands so the front frame lifting pads (behind the frt wheels) are AT LEAST 15” high, 18” is better.
3. I think it would be difficult or impossible to do motor mounts unless you remove: Front Wheels, exhaust crossover pipe, flywheel shield, starter (remove cable off battery first!). (optional: have a nice, small LT4 corvette starter ready to go in
)
4. For supporting or lifting the engine from the bottom, I cut a 7” long piece of 2x10 lumber. Then the floor jack supports the engine weight across the full area of the oil pan, and there was little risk of bending the pan. I also drilled a 1” hole in the wood for the oil drain plug to fit inside, so the wood could rest flat against the entire surface of the pan.
5. After loosening the fore-aft bolt on the stock mounts, the driver side, oddly, was completely free to slide out even BEFORE I jacked up the engine. The passenger bolt required a bit of engine lift to take the weight off the bolt. Remove mounts per HR’s instructions. Working thru the empty wheel wells helped greatly. Air tools (ratchets, impact wrenches ) are REALLY nice to have, but not essential.
6. Have a 7/16-14 (coarse thread) tap on hand, oil it generously and just plan on carefully running it thru the engine block holes to clean up the holes. It helps the new HR bolts go in so much easier.
7. Have a grade 8, 7/16-14 nut on hand, running it over the new HR bolts will remove any burrs on the bolts. (only grade 8 is hard enough to remove the burrs).
8. An impact air wrench rated 3/8 hex bit (“allen head” bit) instead of a regular bit is less likely to round off when torquing the new HR bolts (HR bolts are harder) .
9. GM’s torque spec on the engine mounting bolts is about 60 lb-ft. The fore-aft bolt connecting the engine and frame pads is about 50 lb-ft. This is with threads lubricated with engine oil or antiseize.
10. Most people say to install the driver side mount first because it’s easier. I DISAGREE, and suggest the passenger side first.
Some amount of prying & pushing is sure to be necessary to get both new mounts to line up. The first mount goes in relatively easy, but because they are so stiff and less compliant, the 2nd mount could likely not align at first, with the frame mounting pads. There is MUCH more room working on the driver side, so that’s the one that should be done last.
I wasted several hours trying to get the passenger side to line up, the engine was always 1/8 – 1/4” too high. Finally took off the DS fore-aft bolt, this let me put in the PS bolt, then some repetitive raising & lowering & pushing allowed the DS to easily go in.
