Wrong motor mounts?

[edcole]

I am currently doing an engine swap on my 87 1/2 ton 4wd (v10 model).  It had a 4.3 and I am putting in a 5.7.  I have motor mounts (the mounts that bolt to the block) from a Chevy car.  The lower mounts that bolt to the towers are new from advanced auto.  I got the towers out of a mid to late 70's 4 wd truck.  All bolts and bolt holes lined up perfectly in the frame and crossmember when installing towers also.  The problem I am having is the 5.7 is in, but sits un-level.  The drivers side sits lower that the passanger side of the engine.  I have gone to a local junk yard to look at v8 4wd trucks but the mounts look exactly like the ones I have (as well as I could see as the manifolds are in the way)and there doesn't appear to be any shims in between motor and mount or lower mount to tower.  Went to a local gm dealer and got a gm diagram and looks like they had shims between motor and upper mount.  But could not tell if they are listed for passenger side also.  I am very confused on this and have never seen this problem before.  The frame appears to be straight with no damage.  The only logical explanation I can see is I have the wrong upper mounts or I have to shim that one side up (really hate to shim though).  Did GM make different mounts for 4wd trucks?

[HAULIN IT]

Ed, How un-level is the engine? Maybe loosen up all of the bolts (frame towers, lower mount halves, through bolts, ect.) & lift up on the driver's side, re tighten & let off the lift. If your talking more than 1/2" or so, something else is wrong. The 2wd & 4wd rubber mounts are the same, as are the engine halves. I've not seen a shim used in this application. Does your truck or the one you got the stands from have any signs of a front collision? Good luck, Lorne

[edcole]

     When I put a level across the top the intake where the carb mounts, i have to lift the level on the drivers side by 3/8.  I have measured the frame height very close to where the motor mount towers bolt in and it measures exactly the same at 28 inches to the top of the frame.  There looks to be nothing damaged to the frame at all.  I have tried loosening everything up and lifting the motor and tightening but cannot get that much play out of all the mounts as everything seems to fit pretty snug like it should.  I had my nephew travel 3 hours up to Bangor from Portland yesterday to check it out as he is a heavy truck mechanic that works on these trucks in his spare time and he was stumped too.  I could understand if the bolt holes and bolts did not line up on the towers and the mounts but everything lined up and went in perfectly. 
     Has anyone on here done a 4.3 to 5.7 swap like this and have seen anything like this.  It almost seems like one of the mounts should be different from the other or one side is to be shimmed.  The gm diagram shows a plate on the drivers side with a mounting hole on this plate that a rod goes from the plate back to the bell housing (maybe)?  I do not have this plate mounted between the block and motor mount.  There also shows a diamond shaped shim between upper mount and block.  I do not have a diagram of the other side of the motor to see if these same shims and mounts are suppose to be on that side also but if they are not, that could be the difference. 
     I am a better body man than I am a mechanic and do not enjoy this part of the build at all.  Just can't seem to get past this problem.

[dumbucket1]

are you sure the engine side of the mounts are not mis matched? the mounts for lets say a monte carlo are not as tall as the mounts for your truck. maybe you have a car mount on one side and a truck mount on the other?

[edcole]

Well I figured out the problem, I pulled the motor again this morning and did some more looking.  The frame is twisted on the passenger side of truck.  I am not too good with photos on the forum yet so I will post the link to my flickr account.  Hopefully it works and everone can see the pics.  I am off to a junk yard now looking for a frame.  I just got done last week wirebrushing the back part of the frame too and painted that.  The one positive thing about this project now. it will be a frame off resto now.  I can do a real good job on the new frame (if I can find one) and under cab now.

http://www.flickr.com/photos/30388559@N03/