Trying to build a decently overbuilt supercharged 1.9L for easy 250 wheel horsepower

[Beamer lover44]

I’m trying to boost the 1.9 L but I know how to drive a stick but I want to drive an automatic due to where I live so I want to fully replace the GM 4L30E for Gm 5L40E for the extra gear and more torque headroom plus less mechanical problems due to the GM 4L30E having major issues comparative to its older brother I would think it would be a very simple process. Since it already has a GM transmission, they’re almost practically the same display a little bit more.

 

[Itsa4pot]

Personally I would find a getrag to throw it in. Even though I know you don’t want to drive stick that’s what would give the best gearing as well as free up some hp. But the biggest problem with auto trans swaps is finding a way to control them. The 4l30e was meant to work with the Bosch ecu. The largest issue with that swap is finding/making a trans controller since it’s a fully electric controlled trans. Now here comes the unknowns for me. I don’t know if the bell housing to trans will bolt up since the 5l40 was put behind 6 cyl cars. It would probably require you to shorten the driveshaft since it’s almost guaranteed it’s slightly longer. And if all that plans out can you use the factory 4l converter behind the 5l if the bell housing on the 5l can’t be mated to the m44. Now with all that being said it would be cool to see someone try it but there is a better option that’s more reliable while being bolt on and having better performance figures That being the getrag. However if you go through with it and try it and it works out do a write up on it I’d love to be wrong.