so i had a 999 behind my lt1 with the stock converter and it worked well. now im putting a 700r4 out of an astro van behind my lt1. will the astro converter work ok or do i need one with a different stall speed or bolt pattern?

It should work just fine as long as you had a 4.3 in front of the trans originally.

Stall should be around 2000 and that works very well for an LT1

sweet! it was behind the 4.3 thank you

I ran the 4.3 converter behind my LT1 in my 94 Caprice and loved it. The only down side is you lose a little bit of the at idle creep. If you have really low gears this helps to keep you from driving through the brakes. I personally like the 2000 stall for crawling.