350 to 4l80e questions

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Sep 11, 2020 | 07:22 PM

Crhode79

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350 to 4l80e questions

I have a gen 1 sbc 350 and want to bolt a 4l80e behind it. Its from an LQ4 6.0. Will it bolt up or do I need special parts to make it work. Thanks for the help.

Sep 11, 2020 | 09:23 PM

vorteciroc

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From: Nitro Alley

What year is your cylinder-block?

What year is your crank-shaft? ...GM or Aftermarket? ...2-Piece or 1-Piece Rear-Main seal???

Sep 11, 2020 | 09:28 PM

vorteciroc

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From: Nitro Alley

If you do have a GM crank-shaft that uses a 1-Piece Rear-Main Seal...

All you need is a stock 4L80E Flex-Plate.
Install your 4L80E torque-converter and transmission... Done.

Sep 11, 2020 | 09:29 PM

Crhode79

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I'll have to check tomorrow. Its actually a mercruiser 5.7. Looking online it says because it has center valve cover bolts its a 1 piece.

Sep 11, 2020 | 09:30 PM

Crhode79

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So the flex ate thats in the 6.0 will work then correct?

Sep 11, 2020 | 09:33 PM

vorteciroc

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From: Nitro Alley

No.

Most of the 6.0L engines now have a "Short-Flange" crank-shaft.
You want a Flex-Plate for a "Thick-Flange" crank-shaft (like the Gen I Small-Block Chevrolet 350 engines with a 1-Piece Rear-Main seal).

If you go to buy a stock GM flex-plate for a 1999 Chevrolet Express Van 2500 with a 6.0L/ 4L80E... it should fit.