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tim_mc · 06-19-2021, 08:21 PM

No electronic box needed for 700R4. However, depending on the set up you may need to run a 12v power lead to the lock up solenoid. There are a couple of threads on the forum that cover this. Here's a pic on the transmission lengths. You will likely need to cut down the drive shaft, as I had to since my TH350 was the short tail shaft version. I had my local Inland Truck Parks cut and balance a spare 2-piece drive shaft and install a new carrier bearing after getting the transmission and measuring a couple of times to be sure of what I needed. I was able to slide the transmission mount back about 1" (if I recall correctly) and drill new holes using an extended drill bit to reach the upper rail. Based on the diagram, the 700R4 mount is about 3/4" further back from the TH350 mount.

Also, you will want a later 700R4/460L version (87-93 I think) as they were better built and had 30 spline input shafts (vs. 27 spline on earlier versions). My core is from a '92 Caprice.

06-19-2021, 08:21 PM	#7
tim_mc Registered User Join Date: Jan 2019 Location: St Peters, MO Posts: 434	Re: Can I use a 4L80 trans? No electronic box needed for 700R4. However, depending on the set up you may need to run a 12v power lead to the lock up solenoid. There are a couple of threads on the forum that cover this. Here's a pic on the transmission lengths. You will likely need to cut down the drive shaft, as I had to since my TH350 was the short tail shaft version. I had my local Inland Truck Parks cut and balance a spare 2-piece drive shaft and install a new carrier bearing after getting the transmission and measuring a couple of times to be sure of what I needed. I was able to slide the transmission mount back about 1" (if I recall correctly) and drill new holes using an extended drill bit to reach the upper rail. Based on the diagram, the 700R4 mount is about 3/4" further back from the TH350 mount. Also, you will want a later 700R4/460L version (87-93 I think) as they were better built and had 30 spline input shafts (vs. 27 spline on earlier versions). My core is from a '92 Caprice. Attached Images __________________ 1967 C20, 350 SBC w/Comp roller cam, 700R4 w/3.42 posi, PS, 4-wheel PDB, Old Air AC & GM Tilt column. Last edited by tim_mc; 06-19-2021 at 08:31 PM.