455 in SL/GS...THROUGH BOLTS..USE TOP OR BOTTOM MM HOLES?

I want too make 100% Sure.
A few have said they used TOP.
These are tight and being a pain.
Thanks for all the help on the 350/455 swap in the
72 SLCustom/GSX Replica.

 

Top holes, you gotta tap them thru 90% of the time, alot of times you can take a long prybar and move stuff around to allow them to slip thru

 

Thanks hugger, they're being a pain.

 

A big tapered punch is always helpful. The engine mount is rubber, and it will move around with some persuasion.

 

Metal to metal and simply will not line up with top hole, with MM on eng or off by hand. Acts like March 1970 rubber has expanded.
70 Estate Wagon set for 30 years.
The 70 E.Wagon SF and MMs were in used bottom holes with the welded nuts, but I guess that was only on full size Buicks.
Does it hurt to use bottoms or will it throw everything off and mess everything up or do I just get New MMs? Thanks All

 

Can't use the bottom ones they won't even come close, use the cherry picker to pick up on the engine and maneuver it where it needs to go , ID put some fresh mounts in there tho while your rite there

 

Punch lines up front but not back.
Does it harm anything to use BOTTOM holes on a Skylark?

 

Bottoms line up SUPER EASY, on engine and off.

 

Punch ..Bottoms line up 100% perfect..don't even have to pry, but I don't want to use them if they're not the right holes. Thanks

 

Maybe because the rubber has expanded and pushed metal out?

 

All I had to do was lower eng and bottoms were 100% on, perfect, top no where close... Strange
Will the 1" difference throw drivetain off.
1972 Skylark Custom 350 4v replaced with SF from 1970 Estate Wagon
bolted to TH350
Thanks, I'm stuck

 

Bottoms are 100% spot on, but I don't want to use them if the 1" difference is going to throw things off. All I've accomplished trying to force the tops is wasted 2 days and
strained my back and gut, then this evening scored the oil pump cover while getting the punch stuck on Rt top.
Has Anyone used the 1" lower bottoms.
If it was just OK to use the bottoms, I'd have been done long ago.
Thanks All

 

I have never used nor had to use the bottom holes, and none certainly ever came there in an Abody, you will loose hood clearance, AC box clearance, trans tunnel clearance to a degree, headers and maybe even the manifolds may hit steering shaft, fan will hit the shroud etc,...IE will not work get new mounts and try

 

I done one few weeks ago and the frame mounts were from OPGI and were JUNK, they weren't clearanced for the frame side bolts to pass thru and caused all kinds of issues till I pulled them out and put TA mounts in there

 

These FMs and through bolts are Parts Place. Day of rest tomorrow, I need it..haha..can drive you crazy.
Thanks Hugger
Were the bottoms only used on Full size cars and why don't the tops have welded nuts like the bottoms?
Thanks everyone.

 

Nuts welded on the mounts was a factory thing, and yes, the bottom hole is for the later big cars.

At this point, my advice is to pull the motor up far enough to remove the mounts... then fit the engine mount to the frame bracket, to determine why the upper hole won't line up.

Sometimes the engine mounts have a "nipple" on them, that has to fall into a slot machined into the face of the frame mount. I mention this, because when you run into this issue, the misalignment is about what you have there now.. so check for that, it will become obvious when you just set the motor mount on the pad, and try and slip the bolt thru.

JW

 

Thanks Jim. That's what I was doing in the 1st pick. Didn't see or feel a nipple. I'll check again. Thanks All, Mart

 

You're right Jim the nipple is there on the MMs and preventing the top holes from aligning. Can I just grind them off or do I need to get new MMs.
You know, that was the 1st thing my Dad asked Fri evening "Is there a little tit on there that's supposed to fit in the notch".
Always listen to your Father especially when they were an Air Force mechanic and Pipeliner.
So it's safe to just grind off the nipples? Thanks Jim, hugger and everyone.
Mart

 

With how cheap mounts are, I would just get new ones. Those look "vintage"

http://www.rockauto.com/en/partsearch/?partnum=A2291

 

No problem to grind the nipple. I had the same issue when I broke a MM in BG, and bought a used pass side to use on the left. (Figured it would have less wear and tear...) Dave Hemker's brain and John Schmidt's tools saved me.