Transmission?

[88bluestar]

Rules are automatic or standard, must be flywheel or converter that is of OEM size.
Looking for as little parasitic hp/tq loss to gain any advantage I can. I’ve used both powerglide(10” Hughes circle track converter, can not use that converter in this situation)and Saginaw 3 speed(78 corvette flywheel and clutch). What is oem converter size for a powerglide as well?
Which trans works better?
We have a 6200 rpm pill rule?

[F-BIRD'88]

The Vega powerglide came with a 10" converter.
6 cylinder PG had a 11" converter. V8 was a 12" converter.

[rfoll]

vega converter will need to be tightened up.

[skinny z]

What was in the S-10?

[88bluestar]

What size engine was in the Vega?

[rebelrouser]

If you have to go with OEM style converter and are Looking for as little parasitic hp/tq loss as possible, a manual transmission is the only way to go. A stock OEM non lock up will always have around 10% slippage at least, and more if the converter is loosened for performance. Next question I would ask about the rules is what weight flywheel can I run? A lighter flywheel really makes an engine accelerate faster providing it has enough weight/inertia to get the vehicle going from a start. You said rules say OEM size, but what about weight?

[mag2555]

A manual trans is the way to go for a whole host of reasons if the car is not being used at a drag strip.

Don’t even waste any time considering a auto trans!

[dannobee]

Don't even consider using a powerglide/circleglide/circlematic. You will be changing changing high clutches all the time. I have more experience with those turds than I care to admit. Costly AND maintenance prone.

Use the Saginaw 3 speed and run 10W30 Mobil 1 engine oil in it. Run the lightest clutch and flywheel that you can legally get away with. This is where weight really does matter. And you can practically pick up the trannys for free.

[88bluestar]

Will be on the band, and likely a low stall converter, hopefully less than 2500 rpm

[jsgarage]

FWIW, I've broken stock 4 speed Saginaws with a pathetic stock 305 V-8. Once drove a near-new '82 Z-28 home 50 miles IN NEUTRAL when a gear welded itself to the mainshaft at an autocross, in a gearbox full of factory oil. Had to disassemble using a 20 ton press. The same gears and gearbox were used in the '66-up Corvair and some of them had gear trouble, too. Durability can be iffy.

[dannobee]

Saginaw 3 speed and 4 speed are two entirely different beasts. The 3 speed is stronger and has been used in circle track cars for decades.