Guys with an LS & T56, need your help

[superbon54]

I’m starting the steel work on my 79 Malibu body (its off the frame) and know I’ll need to cut a hole in the tunnel to fit the trans. I will be running a 6.2L LS3 with a T56 trans and the Holley motor mounts. I have all the mounts but won’t have the motor or trans until this winter.

Do any guys with a similar setup have dimensions for the location and size of the tunnel opening? I would like to complete all cutting and fabrication prior to e-coating the body, if possible.

 

[84dragcutlass]

Best way to do that (in my opinion) is to wait. You can cut the hole without disturbing the coating much but every car is different and even with the same equipment It could sit a little different that someone else car especially since you've had the body off. Id hate for someone to give you dimensions and them be a little off and you have to go re cutting anyway

 

[81cutlass]

This thread has good info.
https://gbodyforum.com/threads/t56-6spd-manual-transmission-install-into-a-gbody.60659/

The photo he had on the 2nd page, 1st post is a dead link for me at least. Might we worth sending him a PM to get the measurement. I followed it and worked well.

I did not cut a hole in the tunnel besides for the shifter. I did the math and it was only worth like 1 degree of U joint angle and people lift and lower pickups/jeeps/cars all the time and totally violate driveline angles and generally are OK. I removed a small rubber damper on the top near the rear and gained all the area I needed. You are going to less angle anyways so worst case it MIGHT (unlikely) result in some light vibration at certain speeds.

I did have to hammer the side of the tunnel outwards to clear the reverse shift lockout solenoid. Cutting that out and welding in a hump could be helpful also.

Basically, cutting the tunnel out works but isn't worth it according to my measurements.

 

[jlcustomz]

Motor mounts play into this also. I did mine in 2002 before all the parts & info you got now.I slit the top of the tunnel & spread it. Also hammered out area for reverse lockout.
Someone has a cut & weld in prefabbed trans tunnel now.

 

[superbon54]

Thanks for the responses guys, very helpful! Sounds like each install is a little different, so as much as I want to modify everything at once I’ll most likely wait until I have the motor and trans.