Frame flex and trans/engine mounts

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I replaced my 350 and 3 speed in my 1972 with a 350 and a Toyota 4 speed. Has the Downey front saddle mount to the stock 1972 F motor frame mounts, and new AA trans cross member. All set and level etc, but when all bolted up, there is a 1/2 inch or so gap at one corner. Passenger front or driver rear, depending on how you tighten down. Is this a cause for concern? I have heard these frames have a lot of flex, wondering if setting for a few months without a drive train in it allowed for the frame to tweak a little? So to pose a question, bolt it all down, it will flex and right itself? Or, a half inch spacer at one corner to offset whatever is causing this?

I realize I could have a twist in the frame, but I can’t seem to see it so far.

Thanks in advance!!
 
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Driver rear. Washers for spacers. Cross member hits body. This is where I have spacers. If I bolt this down then the opposite corner passenger engine
 
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Driver rear. Washers for spacers. Cross member hits body. This is where I have spacers. If I bolt this down then the opposite corner passenger engine.

Apparently, I need to update my status. Won’t let me post pictures. I will pay up and then post a pic.
 
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D95048A0-2940-4485-BF53-42C64150B9B8.jpeg
 

pb4ugo

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You're frame could be tweaked, but it really doesnt matter. Did you have the frt mounts bolted down while determining where the rear mounts go? Did you mount the rear frame mounts in the same place on each side of the frame, or did you have the rear crossmember attached with the frame mounts bolted on, to determine where the mounts should go? I see your mounts are bolted to the frame. Instead of spacers, adjust both rear mounts with frt mounts bolted down and then weld in the rear frame mounts while they are bolted to the crossmember.
 
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All good points. The bigger issues is it sits high enough off the mount to rub the body. So I will probably just spacer the the front passenger and then adjust when I get the side engine mounts welded in.
 

pb4ugo

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All good points. The bigger issues is it sits high enough off the mount to rub the body. So I will probably just spacer the the front passenger and then adjust when I get the side engine mounts welded in.
It all makes sense now. Go for it. Make sure you don't put the driveline in a bind.
 
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whats the pass side rear mount look like ? FWIW thats almost identical to where my mount bolt/nut comes out, I think I even carved a bit outa that rib under the body.
IIRC I had to modify the pass side, Make it smaller/shorter to solve this issue. I think I trimmed 3/16 or so off of it, cutting it in half is too much.
 
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My adapter plate clocked my tc a bit, so my AA crossmember had a bit of a cock eyed angle. I notched it an inch and half to clear the floorboard- never had any issues. You’ll be fine clearancing it a bit. Those things are way over built.
 
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To check if the frame is twisted, put the frame on 4 jack stands , use some different plywood shims to make it site level
if you can not make the front and rear bumper level , the frame is twisted
Without having the time to jack stand it, I checked the level of the bumpers and the frame height at all four corners. It’s dead on and level. But I will jack stand it and check, all the same.
 
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Archie73 is correct, that propeller mount is not level , or the pass side and driver side do not sit at same heigth in respect to frame. It sits at a slight angle which tends to put pressure on the outside of pass side mounts, typically that rubber is squished at an angle. Tighten motor mounts, set desired heigth of tcase with pass side mount at rear of tcase, once that is done you can see what size mount/spacer/bushing you need on the driver side rear tcase mount. Makesure the tcase drain plug is not contacting skid plate.
 
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I’m probably making a bigger deal than needs be over this? It’s all of 1/4 of an inch after I slide the washer in there. If I can slide a washer spacer under the passenger motor mount, between that and frame flex, I’m wondering if it doesn’t just flex itself out.

4C122894-0ACB-4582-B172-6E93E95A7973.jpeg
 
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I say tighten the motor mounts, no spacers, set the pass of the propeller rear mount first, and I am refering to the height of the tcase, IMO as hi as you can go without causing shifter clearance issues and not stuffing the driver side into floor. Add spacers to fill the gap on the driver side and suck it all down, not ridiculous but tight, I check those before I leave and when I get to camp. If they are loose it causes popping out gear issues among other things. Do not try and space the motor mount IMO.
 
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If all the mounts are new and the mounting pads are set at the same height, side to side, the 1/4" gap may be the result of the transfer case hanging on the passenger side. The weight of the transfer case is torqueing things and causing the gap. The rear crossmember is supposed to be straight across. Take out any extra washers/spacers and bolt down the crossmember. The six bolts on the transfer case will torque things into place.

If the engine mounts are old, it's possible the one on the drivers side is actually broke allowing things to torque over easier. It may not look broke with it bolted up and you'd need to pull it to see the separation.
 

Downey

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Your front motor mount rubber cushions are mounted on an angle in slots that will let them slide up or down, perhaps the remedy would be to loosen the front cushions and let them slide/find a new comfortable home in their slots (with rear crossmember mount cushions already tight), then tighten down front cushions ???
 

pb4ugo

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All good points. The bigger issues is it sits high enough off the mount to rub the body. So I will probably just spacer the the front passenger and then adjust when I get the side engine mounts welded in.
According to the OP, this situation is temporary. He plans to adapt proper frt motor mounts and gussets, which will alter the location and fitment of the driveline. I suspect the engine will sit slightly lower.
 
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Your front motor mount rubber cushions are mounted on an angle in slots that will let them slide up or down, perhaps the remedy would be to loosen the front cushions and let them slide/find a new comfortable home in their slots (with rear crossmember mount cushions already tight), then tighten down front cushions ???
Damn. I didn’t think of that… could just lift engine and reposition. Thank you all of you!!
 

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