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I got new tires and can actually do a 1st gear WOT pull, but I just cut my second upper radiator hose. I'm thinking I need motor mounts as there seems to be plenty of clearance between the hose and alternator. I've used the Polyurethane mounts before on a 72 Monte Carlo with a 502, but not sure how they work on a Corvette. The engine is mostly stock 400hp 427, with a 268 cam. Will there be too much vibration with the Polyurethane? Which would you guys recommend?
Go old school and use a chain to limit how far the motor can move, with just enough slack that it doesn’t transmit vibration.
There was another old school method of drilling through the mount and tapping only the frame side of the mount and installing a bolt with a little bit of clearance under the head to allow vibes but limit movement. I seem to remember the head of said bolt would fit inside the freeze plug so no worries on clearance. Can’t recall if this works in Vette mounts though.
Edit: I also remembered there is a “safety” version of the motor mount that has part of the block side in a t-shape bent up over the frame side to act as a limiter. But I think those didn’t work with spark plug shields.
Last edited by wwiiavfan; Jan 23, 2022 at 04:35 PM.
Please allow me to share my experiences from last year. I went through examining 3 sets of motor mounts before ordering the Corvette Central pair: 1pr from Rock Auto, 1pr from NAPA, and 1pr claiming to be USA originals from eBay. Except for the CC pair, all others appeared to be Anchor 2285 resales. The Anchors were very sloppy on the frame horns of my '72 and didn't seem to matter if made in the US or China. The Corvette Central pair were the only ones that fit the frame like the originals – a snug slip fit. Before ordering, give Zip a call to confirm they are made by CC.
Super dumb question. Is that the OE radiator? What kinda shape is the core support and the radiator support pads on the bottom look like? Could be that the radiator is bouncing downward just as much as the motor is coming upward. Or it could be a fitment issue for a non OE radiator. Could be the mounts but figured I would throw it out there to make sure you look at this angle as well to make sure you cover the problem.
Super dumb question. Is that the OE radiator? What kinda shape is the core support and the radiator support pads on the bottom look like? Could be that the radiator is bouncing downward just as much as the motor is coming upward. Or it could be a fitment issue for a non OE radiator. Could be the mounts but figured I would throw it out there to make sure you look at this angle as well to make sure you cover the problem.
Thanks, its a Dwitt's rad - pretty sure it's secured but I will double check.
When I 'pulled' the L36 (and installed the 489) it was only then that I realised that the driver side (interlocked) mount had separated. New engine had 50% extra torque so installed a new (albeit dubious quality) mounts - the drivers side one lasted exactly 100 yards before pulling apart and allowing the fan to start 'eating' its shroud............installed a pair of poly mounts some 7 or 8 years ago and its been fine since - gearshift quality improved too - and lost the dreaded dashboard judder.
So I got both the correct locking motor mounts and the solids. I installed the stock locking ones and everything seems fine but the engine rocks quite a bit at idle. I've always used performance mounts in the past, so I wanted to know if this is normal for stock-type mounts. The cam is an older Erson 268 hydraulic, so I expect a little bit of choppiness. The ignition is all new and the car runs smooth off idle.
Why did you not use the solid mounts that most people suggested ?
The solids were brought up after I put the order in for the stockers. That is why I ended up with both. The car is pretty stock appearing, so I decided to try the originals first.
Big Block motor mounts
