I did a search, but after 15 minutes or so...decided to just ask the question: What size are the 3-1/2" long bolts that connect the motor mount to the frame-side stand?

I believe they are 7/16" - 14 X 5". However, if you can get factory bolts, they are easier to install because they are pointy on the ends and can be tapped through with a hammer. I think the GM part number is 3988696 if they are still available.

I just have an issue with my new frame-side stands and how the new motor mounts fit over them. The holes do not line-up very good. Either the motor mount is wrong or the frame-side stands are wrong. With the motor mount bottomed on the stand the holes are not lined-up by nearly 1/8". I suppose I could take a die grinder to the holes, but I hate to bastardize new stuff. I am going to go check with a stock motor mount today at lunch to see how it lines up. I don't think I could get a 7/16" thru bolt all the way thru both holes.

The last time I had that problem, I was able to loosen the bolts holding the mount to the block and move it around . There was a difference in final position right as you tork down the bolts to the block. Maybe worth a try?

This is not even on the motor. I have the new frame-side stands and the new motor mounts sitting on the table and I can't get the bolt holes to line-up! I don't think they should be that bad from the start and no amount of engine weight is going to change that. I don't want to get to the point of trying to bolt them together after I have wrestled getting them changed over in the car and find I can't get the final connection made!

Remember Super Shops? I got a set of motor mounts form them years ago to put a big block in my 71 Nova, and I had the same problem you describe. Turned out they were the wrong mounts. I knew that 68-72 Novas had the same front subframe as 67-69 Camaros, so I went to NAPA and got motor mounts for a 396 Camaro. They fit like a glove. Hope you figure it out.

I am sure you could grind on em like you said.If they are that goofy, I would just get a different set.Not worth the trouble. I like the Lakewood Muscle Mounts.

I'm sure I'm not the only one that has had this problem, but check the rivets. One time I bought some that were the same shape but had pan-head rivets. The correct rivets are flat head.

Thanks for all the replies. I have Lakewood Muscle Mounts...have used them before. I got the 350/BB frame-side mounts from a local Chevrolet dealer. They are the proper outer dimensions and all, the motor mounts have flat rivets and I checked that they were minimum flush with the surrounding metal. My choice is to either grind on them or get a new pair from one of our Aftermarket Chevelle parts stores. The frame-side mounts aren't beautiful in their manufacturing...so...could be junk ones...don't know. Being in an OEM business I think they look a little like a 3 yr old was running the press. Not sure if that is how all of the aftermarket ones look.

Went to the local N.A.P.A. and test fitted a stock replacement motor mount...same issue! I think I may try new frame-side mounts.

The early chevy's used several different size mounts. If you don't have the correct mounts bolted to your engine, it will never align correctly with the frame mounts.

See the various sizes:
http://www.moroso.com/catalog/categorydisplay.asp?catcode=28100

Click the 'appl chart' link to see a list of the various mounts and their intended application.

I've used #62500 and #62510 on various cars. I have yet to ever need changing the frame mounts.

Hope that helps.

that's what happens when you try to bolt an engine side mount that was made in India to a frame stand that was made in China.

Just a quick little update...I finally received my new Frame-side Stands from Ground-up and checked the fit to my Motor Mounts. THEY FIT PERFECTLY!!! The main thru bolt holes line up and everything feels and looks as it should. The box the Frame Stands came in had a label of TWE. Needless to say they look and function much better than the ones I got from my local Chevrolet dealership.

The only thing that was different was that GU or TWE had the stand with the round hole marked RH and the stand with the slot unmarked...making me feel that was suppose to be LH...however...I know from my Parts and Illustration catalog that the slotted stand went on the RH side of the crossmember. I don't know if it really makes a difference to which side it went. The small amount of variation that is allowed anyways is probably only for assembly tolerances and I doubt that it would make much difference alignment-wise for the engine.

I'll second the lakewood mounts.:yes: