Howdy!

I’m not exactly bewildered just not very experienced. I ran small high stall converters behind hot rod slant 6s before so that I didn’t have to idle real high and jolt into gear to make up for poor idle quality. I have more experience with gnarlier cams etc in small blocks with stick shifts so I understand a performance powerband but never played with big boy converters. Since I’m on a tight budget I kind of still won’t be!

Here’s what I have going on: I’m building a mild 400/512 stroker for the street and putting it in a 1954 dodge pickup on an 89 dakota chassis. I own three 8.25 rears so for now I’ll be laying one stripe with the stock 3.21 one legger. Hopefully a light vehicle & lack of traction will make the rear (and 2 spares!) last until I can go dana/4link or whatever I decide when my wallet recovers. The motor is getting stock stealth heads, 10:1 cr, comp 507/510 (240°/246°@.050) cam, 1 7/8” headers, rpm intake, 750 holley. I’m going for torquey and responsive more than max hp.

I’m anticipating somewhere north of 350hp/400tq at the wheels with gobs of torque all over? I am confident the big stroker will love the 3.21 gear. I feel like if I had a strong rear and traction a 2500/3000 stall would be a stoplight monster but traction/strength limited all it would do is drive mushy and hot at mid throttle or constantly burn rubber? With a 727 and 3.21 2500rpm is 35mph. I’m guessing my combo won’t need 1250rpm in N just to idle at 850 in gear?

I have a stock converter sitting here that will cost zero to stick in there, or I can afford to grab something like a $300 2400ish stall. Also I have a slap shifter to control it. It’s the kind that you can put it in D or slap your way up from 1st and chirp the shifts. Should I do anything extra to my trans while it’s out for this combo?

Thanks moparts!
Radar

Keep in mind that some of the hairiest cams ever factory-installed in a Mopar were the Max Wedges and they also were fitted with the tightest converters ever installed in a 727 and they idled just fine in gear.

There's a lot of pieces to the puzzle. While it's good you're planning ahead, without a Dyno chart this is going to be best guess.

I'd stick the stock converter in after it's together and see if it wants more. My guess though is it's going to be pretty close if this is a mild build like you say.

I would look for a stock 11.0 inch Street Hemi or one out of a 383 or 440 magnum so it will work with the 1966 and later 727 trannys, there not real loose or real tight either. The big stroker motor should make it act looser than if it was behind a stock magnum motor
One of the old Mopar drag race engineers said at one of their seminars back before 1980 that the loosest stock 11 inch converter Mopar made for production vehicles was for the 1970/71 383 two barrel motors in station wagons
I have ran a custom built 8 inch Turbo Action race hemi converter in my old pump gas street Duster with a bunch of different gear ratio, 3:73,3;91,4:10 and 4:30 in the 8 3/4 in that car, it loved that converter and so did I It was way better on the street than the custom built ten inch converter I had built for that 511 C.I. pump gas motor
Torque converters and brain surgeons are two thing you don't want to skimp on AKA aside, buy a really good one
IHTHs

My 9:1 493 with an MP509 248@.050 drove around fine with a stock hi stall converter and 2.76 gears but I got tired of the way the 1100 RPM idle pounded the driveline when you put it in gear. I put in an off the shelf 2800 TA converter from Mancini and it took all the bang out of it but it's still tight enough that it will drive away at idle on level ground. This was in a 4800lb Cbody.

Kevin

Your motor is very close to my build. I'm running a roller cam with 240 degrees of duration, OOTB Eddie heads and 10.5:1 compression. It did have a 770 Holley on it for the first year and I just swapped over to a Sniper EFI.

That thing is going to develop a crap ton of torque. Whatever converter you decide on, make sure it's a tight one - you don't need a lose converter with a motor like that. A tight converter will make part throttle cruising and throttle response much more enjoyable.

The one I'm running now is a Turbo Action 17809ST. It's specifically made for transmissions that have lockup input shafts, but it doesn't have the lockup internals in it.

Give Turbo Action a call, you won't be disappointed.

PTC builds a nice street converter. Last one was $450.
Doug

IMO you're better off using one of those stock converters before using a cheap high stall. Save the $300 and put it towards a better converter