Converter stall check

[MT71c-10]

Hey guys. I want to check my stall with you guys.

71 Chevy c-10, weighs in at 3700. Edel. RPM 64cc heads, RPM cam, RPM air gap manifold, roller rockers, hyper flat top, 1 5/8" headers, 3'' collector, 2.5" dual, h-pipe, Edel 750 carb, th-350, 3:73 rear gear, 275-50-17 yokohama advan s/t tires.

It has a supposed 2800 stall, but i'm getting slow launch, Hard to do standing burnouts (without the help of some gravel or water) and when it goes from park to drive it has some rpm drop 3-400 rpm. Truck runs like an ape at 3100 rpm up, a little lazy below.

Now I know the RPM stuff works best on lighter vehicles, but I like that top end scream. The Edel carb will be replaced with a Holley vac sec 750.

The converter builder wants $175 to restall, so I want to check and see what stall I really need to run, or if a stall and regear is in order.

Thanks for the help.