I want to overbuild it to handle 1000 horsepower but a few shops said it can't be done unless I find the parts for it. So does anyone know what parts will achieve this?

 

Anyone?

 

When it comes to a built auto trans you are limited to parts available for that particular model. Most out there the upper limit seems to be around 800 hp. The only trans that I know of that can handle 1000+ hp is the old two speed powerglide.

 

Level 10 has a bullet proof kit for it. A company called Oregon Performance Transmission has a high performance kit as well.