height of transmission tunnel C10 and C20

[kikkegek]

guys,

help me out. a friend of mine and me are both doing a TH400 to 4L80E swap in our Suburbans.

both have 454 big blocks and are original 2WD, automatics (TH400) and were stock before we started on the conversion

he finished his C20, just moved the crossmember back a little, shortened the driveshaft and had no problem fitting the 4L80E under the transmission tunnel.

when I tried to install the 4L80E back on the crossmember that I moved back I hit the bottom of the cabin before I could get it up on the crossmember.

we did a lot and I mean a lot of comparing the last few days.
- cabin bushings are the same
- engine mounts are the same
- crossmember is at same height compared to the frame/chassis

to come to the conclusion that the transmission tunnel of my C15 is just not as high as his C20. his is about 3 inches higher above the transmission.

did anybody else have the same experience? maybe some GM technicians on here that can confirm?

I am going to cut up the transmission tunnel tomorrow and raise it, just curious if somebody can confirm and did the same swap?

this is the link to my project page: https://www.facebook.com/77suburban/

this is my 77 GMC C15 Suburban "STORM"