[Steves65]

I have a 2400 lock up converter now, but according to the Barry Grant guide for the 675 Race Demon RS I need a 3000 stall converter. I don't mind buying a new converter but I was wondering if I would screw up anything by doing so.

383, RPM Air Gap intake, Comp Cams XE274 cam, AFR 195 heads, TH400 trans, Currie 9" Ford rear end with 3:50 gears and detroit locker. 26" rear tire.

Max power on the dyno was at 5500 rpm, max torque at 4500.

Thanks,

Steve

[427L88]

Steve, while being no expert on the carb you have, I would not install a new converter unless it fit with your performance goals. Good ones aren't cheap. If it is a vacuum secondary carb, you'd want a slightly slower opening with your tighter converter is all. tighten up the secondary opening rate some.

[GOSFAST]

The higher torque 383's raise the stall in any convertor. If you go smaller, (higher stall), you'll be in a "slip-state" when driving normally at highway speeds due to the low(er) rear gear. I don't get involved in convertors anymore, we use to build them to our specs, but I think you'll be fine with an 11" (2400/2800) unit. You'll probably "stall" higher than you think with you're engine. The car weight also is a major factor. Thanks, Gary in N.Y.

[boldm]

on the strip my truck (in sig) ET'd 3/10th's quicker in the quarter mile vs the 2400 stall last year, NO OTHER CHANGES. I assume you have a 700R4 when you talk lockup. Not only did I improve my 60 ft, but down track performance improved as well because a 2400 RPM stall will definately drop below peak torque on the 1-2 and 2-3 shift, even at WOT whereas the 3000 will keep it slightly above. You will not be disappointed with a 3000 stall, especially with the lockup feature.

[greg_moreira]

3000 aint bad at all for that cam in the 383. Typically, you dont want your actual stall speed to exceed your cruise rpm by a large margin. So, for example, if you cruise at 1800rpm, a 3500 converter can create excessive heat. This is cause you are cruisin at only 1800rpm, and the converter will still be loose cause it can stall roughly 3500rpm(depends on torque, vehicle weight.......)and all that slippage creates heat. Heat is the number one killer of trannies.

But, here is what confuses me. You say youve got a turbo 400 tranny with a lock up converter? Typically they dont have lockup converters unless you are talking about one of the more rare ones that do actually use lockup converters(the TH400C I beleive). If this is the case, you are perfectly ok cause all youve got to do is lock up the converter(wire it up with a switch so you can lock it up manually)......when it locks, no slippage, and no more heat than usual. If this isnt an actual lockup tranny, than its not really a lockup converter. Unless its an honest lock up converter like in your overdrive trannies, no converters ever really lock. There is always some degree of slippage reguardless of the stall speed and reguardless of your engine rpm.

But, with your 3.50 gears and 26 inch tall tires, you will need to spin almost 2800rpm in the first place to cruise at 60 miles per hour. So what Im saying is that your "cruise rpm" for 60 mph would be at least 2800. Thats darn close enough to 3000rpm that heat wont be any more of an issue than it is now with your current converter, so you will be perfectly safe with a 3000 converter, and safer yet if it really is a lockup. Just get a good tranny cooler if you dont have one(I dont mean the cooler in the rad, I mean an aftermarket tranny cooler).

[Steves65]

Thanks guys for all the tips... the TH400 I have is not a TH400C so my terminology was off a bit, but thanks for the education. My cruise speed is 65 mph and tach is 2940 rpm. Do you have any recommendation as to brand or model of torque converter to use?

Also a trans cooler was recommended.... I already have an oil cooler mounted in front of the radiator so I am not sure I have room for one there. I am running an aluminum 2 core radiator with internal trans cooler at the moment. Any ideas on where to mount the cooler other than the radiator that would be efficient??

Thanks again,

Steve

[Theo]

My '68 came with engine oil cooler and I installed a tranny oil cooler. It was a tight fit but it is doable. I installed both of them on the driver side of the opening. You just need to make your own mounting brackets with steel or aluminum strips from your local hardware store.

Theo.

[greg_moreira]

If you look around and get a little creative, you oughta be able to find somewhere to put it. If worst comes to worst, you can buy a cooler with a fan on it. this way, you can mount it basically wherever you want and its not that big of a deal if its not getting the greatest airflow to it cause its got its own fan. Anyways, as far as converters, there are plenty of good converter manufacturers. Coan, ATI, Hughes, BTE, ....... I like Coan converters, as well as Hughes if your buying one of their custom made ones.