LT4 with 8 or 10 spd trans swap help & questions

[redmanf1]

I have been checking out the 2017-2020 LT4 ZO6 engine with an 8 or 10 speed trans. Has anyone done this swap on a 70-72 Chevelle with factory AC? What swap parts would be the best to use? Will the trans fit without cutting the trans tunnel? My BB chevelle convertible has been restored and I really do not want to cut it up. It currently has a 496-roller motor, 400 turbo and 12 posi bolt rear. I like the power of the LT4 with pulley change.

Thanks for any help
Nelson


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196093

[dhutton]

Ground clearance of the trans pan would be very poor without cutting the tunnel, assuming you could get decent driveline angles which is also doubtful.

Don

[redmanf1]

Any other info??

[CarlC]

That's a pretty complex swap.

Very likely the trans won't fit without modifying the tunnel.

I don't think anyone makes any kind of bracketry to keep your AC compressor. There's just not enough demand.

[redmanf1]

I do not mind changing the AC compressor. I just do not want to change the AC suitcase. The vintage air takes up too much room inside the car. I know the 4L80E can be installed without cutting the tunnel and no ground clearance issues.

[srode]

Most supercharged motors have nice flat torque curves, so you don't really need 8 or 10 gears to get into the power zone, just need something that won't break under the torque.

[redmanf1]

I have seen several for sell on eBay so I know someone has been doing them. I would think GTO (lamans), 442 (cutlas), GS (skylark) would all be the same as the chevelle (SS) because they are all A body's. I guess the 4L75-E is used on the new connect & cruse setup.

[dhutton]

A bodies have a tunnel that is even smaller than first gen F bodies. I can virtually guarantee that you will be doing some cutting based on my 6L90E into a first gen F Body experience. I also had to make tunnel mods installing a T56 into an A body. A bodies are not that swap friendly when it comes to larger transmissions and lowered ride height.

Don

[HotWheelz]

Checkout my build Thread.

You will see the fabbed tranny tunnel to fit the 2018 Lt1 and 8 speed into my 1966 Nova SS:

Page 5

https://www.pro-touring.com/threads/130072-1966-Nova-SS-Build

[79 Camaro]

Can't offer any advice about fitment but maybe 8 speed versus the 10 speed.
My 2015 Silverado 6.2/8 speed combo was great except the 8 speed was not great. When it was cold the 8 speed always shifted hard 2-3 and 3-4. Sometimes on the down shift coming up to a stop light it would shift really hard down to 1st. Programming changes at the dealership were no help.
The truck never left me on the side of the road. Over on LS1tech the 8 speed doesn't get much love.
My 2020 Silverado 6.2/10 speed is so much better. Kind of fun to watch it shift rpm wise. No hard shifts. Via a selector on the dash you can have normal, tow and performance shift points.