YenkoST

iTrader: (11)

Hey guys(gals);
I need some torque converter advice. I have a 1990 Chevy truck with a 700R4 and 3.73s gears and its my daily driver. I have a 383 in it with heads, cam, and MPFI system pushing over 400+hp. What's a good stall to go with? My tranny is the stock unit but it does have a shift kit, vette servo, .500 boost valve, and tranny cooler. I was thinking about a 2500-2800 stall but need some advice on what brand, stall, STR, and if it will hurt my tranny life? Thanks for answering those questions.

James B.

iTrader: (1)

The higher stalling torque converter will put more stress on the geartrain due to higher torque multiplication - especially on launch.

Really need to know what RPM you are shifting at and also what your torque curve for the engine looks like to make an intelligent recommendation.

YenkoST

iTrader: (11)

I am shifting at 5500 rpms and torque curve is pretty flat from 2500 to 5000. Peak torque is about 4300rpms.

James B.

iTrader: (1)

I think the torque peak for the TBI that truck came with had to be something around 2500! With a peak up that high I really think you need more stall speed than that. I would say 3000-3200.

YenkoST

iTrader: (11)

well...i don't have the stock engine. I have a 383 with AFR heads and a Holley StealthRam MPFI system pushing about 425-450hp. That's why my power ratings is a little bit different. That's why my sig says, not exactly stock.

This is my daily driver right now too so it needs to be very streetable. It will only see the track like once or twice a year maybe if ever.

What STR in a converter would be better too?

James B.

iTrader: (1)

I realized before it's not stock. No stock truck engine would have a torque peak over 4000 - an RPM alone the old TBI could barely exceed anyway. The torque converter stall speed you mentioned originally would be too small for your current engine in my opinion which is why I would suggest something more: 3000-3200. My point was that the lower-stall converter would have been a better match for your old engine than the current one. Anything with a cam enough to peak over 4K need more converter or it's giving up a lot off the line.

YenkoST

iTrader: (11)

Yea, the holley stealthram is a tunnel ram designed form teh TPI system. Yea, a 3000 probably would be better but still want to retain some driveability right now you know.

What about the STR, what do trucks like?