[sbc307]

I'm building a 1969 Chevy C10. Its done for now, but later i plan on doin more to it. The question is how big of a stall on my converter should I choose? The motor is a 307 bored 0.30 over, block decked 0.20 off, heads are World S/R Torquers 58cc chambers, stainless valves, decked 0.20 off, total of 0.40 off to bring compression ratio up to 10.1 on premium gas. Has a Comp Cams hydraulic big-thumpr cam #K12-602-4, 243 intake, and 257 exhaust duration @ 0.050, 500 intake and 486 exhaust lift, 107 lobe center, double Isky valve springs #6005, 8.000 inch Summit pushrods, guide plates, 7/16 screw in studs, Harland Sharp roller rockers 1.5 ratio, HEI street/Strip distibutor ProComp, Edelbrock Performer RPM intake, both heads and intake port and polished to match, with fel-pro gasket, long-tube headers, Holley 700cfm double pumper no choke. I building up a 700R4, with all the good stuff, billet servos, best clutches you name it, its Monster Transmissions master kit good up to 600 hp, its over kill but for $800 for everything its worth it. Im thinking of using a 4800 to 5000 stall converter. Let me know what you guys think. Thanks, sbc307.

 

[XNTRCI-T]

How will this vehicle be driven... street/strip, daily driver, race only or what?

 

[sbc307]

How will this vehicle be driven... street/strip, daily driver, race only or what?

Sorry about that forgot to put that in there... it will be mostly street driven, will hit the track once in while, so yea street/strip. Thanks, sbc307.

 

[XNTRCI-T]

Well, I'm not an expert, but since no one else has responded, I'll give you my perspective. I think 4800-5000 is way too much for a vehicle that is regularly driven on the street. I don't think you will like it at all. You're going to be revving up into the 3000-4000 range just to leave a stop light at normal speed. Your gas mileage will be terrible. You're going to need a good tranny cooler to take care of the excess heat you'll be generating with all the slipping in the converter at city and even highway speeds.

I'm running a 3000 stall in my blown 500hp T-bucket that weighs about 1800 pounds. Under normal accelleration from a stop light I see about 2200-2400 to get rolling. In normal city driving during the summer I see tranny temps of around 220 with a good tube and fin cooler. I'm adding a fan to the cooler this winter.

Why do you want/think you need 4800-5000? That is pure competition range in my opinion.

 

[sbc307]

You are not far off on your converter stall selection for your radical 307.

The advertized stall speed of your typical off the shelf high stall converter is rated when used behind a 350ci motor. Whewn used behind a 307ci motor, you can expect a actual max stall about 500rpm less as the smaller ci motor makes a lot less torque.

This combo will need a very stiff rear gear ratio. at least 4.88:1

Getting the rear gear ratio and converter stall right is critical to the sucess of this comb.
I'd pass on the OD trans and use a th-350 and 8" or 9" converter as this motor is going to want to rev.

Thanks, the converter is 9 1/2. The only reason I was gonna run the OD trans, is if I go on the highway I can pop it into OD and save some gas, but if im in town or getting on it, I'll just put the shifter in regular drive, so the OD won't kick in, but the TH350 has come to mind also, either one of these trannys, I can get easily. The rear gear, i was going to put a 4.11:1 back there, but if you thing i need an even lower gear i'll look into that. I didn't do any of this stuff yet this is probably for this winter, right now im running the truck with a 3 speed and 2.78:1 rear highway gears and the motor don't like that 3 speed at all, wants to start off slower, and the rear gear aint helpin any!! lol Thanks, sbc307.