[bad2be]

I have a 2 speed power glide transmisson
Do you know what size stall converter i need

[Jmark]

no, not without all the other info on engine, rear gears, vehicle weight and desired usage.

[bad2be]

I have a modified 350 4-bolt engine with 500hp or more
86 step side chevy truck with 273 gears for drag and street

[Triaged]

A few notes:
1) I have a hunch 500hp is wishful thinking. What parts do you have in it that makes you think it is at 500hp? What heads, cam, carb, compression, fuel, etc...
2) You need gears bad! If you are actually making 500hp it will be above 6000rpm and you will never get there with those hwy. gears. Time for some 4.10's at least!

[bad2be]

I have a 510 530 lift lanati cam
I need to know what stall to go with a 2 speed power glide tranny
It is a 350 4-bolt main bored 30 with 12 to 1 dome top pistons
510 duration 530 lift lanati cam standard crank turned 10 10
300 horse heads with valve seeded and the springs to match cam
team G intake 750 holley dual line carb. accel distributor accel coil
with msd firing box 2 speed power glide tranny 3500 stall 411 rear end gears.
how much hp do you think i'll have from your opinion.