Witch way to go auto or standerd trans

[Streetmaster]

Hey guys im new at the board so be gentle with me. Got a ? about my project PU witch is a 1976 GMC Sierra short bed, that had an inline-6 with a 3.11 first gear saginaw 3speed. I've got a 9.0:1 c/r, .030 sbc 350 motor, world product S/R Torquer heads with beehive springs for a roller cam. A Comp # (12-422-8) Retro-Fit roller cam, the cam is in the 1600 to 5400 rpm range, and can be used with a stock stall. An Edelbrock EPS performer @ 600 cfm carb, that im going to install when the weather breaks. the truck also has 3.40 rear gears aswell. Now my ? is will the saginaw 3 speed, that came in the truck, hold up behind the discribed 350 motor, witch should have around 325 hp. Or would i be better off with an automatic, like a TH350 or TH400 :::: A 700R4 or a 2004R is way above my budgit at this time. It is also my understanding that an automatic can eat up 10% to 30% of hp, just from slippage of the torque converter, whare as the standerd would'nt slip once the clutch let out, putting more torque to the wheels. The truck weigh's around 3,900 lbs, and would benefit more from witch (auto or stick)?

[Tom]

Your transmission will hold up fine, better then a stock 700 or 200R4 overdrive. Auto's don't loose the power from TC slippage, but from having to turn the auto trannies fluid pump. The 2004R, 700R4 and th350c all use lockup torque convertors that means NO slippage when they're locked, yet you'll still see around 25% power loss to the rear wheels. Manual trannies are in the 15% range. Go with what ever tranny you like more. Personally, I'll never have a automatic again.