Motor Mounts

The idea of replacing the motor in my little malibu from a V6 to a V8 started before I owned the car, but that part of the project continues. The person who swapped the motors welded on the frame side motor mounts even though it should have been a bolt on fit. Small block chevy V8s were a common option on this car, so it should have been simple to make the switch. Something didn't work out though and now I'm have to figure out why it didn't bolt in to place correctly.

The first step was to see if I had the correct motor mounts and brackets. The frame side mounts are fairly universal to Chevy after around 1973. The motor side brackets are a bit more of a mystery. Mine are both the same and have 334971 stamped on them. Surprisingly, information on this part # is hard to find. It seems that it was later changed to 10213125. Same part, new number.

Some vehicles used different engine side motor brackets for the left and right sides, but it appears that G-body vehicles used the same brackets for both sides. I never found definitive info to support this, but I'm going forward using this assumption since more opinions than not take this stance. It's interesting that it is not easy to find this info.

As far as mounting location for the frame side mounts, here's some words from Ray the Rat's Elky FAQ:

V6 installation, the motor mounts are mounted in the rearmost position on the front crossmember. When installing a V8 (this applies to Chevy smallblocks, since that's all I have direct experience with) the mounts need to be repositioned to the frontmost position on the crossmember.

This can be tedious at best, since there are nuts inside the crossmember that need to be held as the bolts are removed from the top. Several methods have been used to accomplish this. Some people have used a combination of socket extensions and knuckle joints, some have created their own wrench by welding a piece of bar stock onto a box-end wrench, others have used a hole saw to cut a hole in the crossmember to allow access to the nuts. I've also been able to do this by removing the bolt that retains the lower control arm and lowering it with a floor jack, then accessing the nuts from the end of the crossmember.

Thanks to Ray for the helpful explanation. I think, though, for now I'll leave the mounts where they are. If I start the process of breaking the welds and repositioning the mounts, who knows how far it'll go. I'd certainly have to alter the exhaust pipes. I think I'll wait for now.