Torque Converter stall speed- need help

[SkysTheLimit]

I got the go ahead from the finance department (aka the wife) and will be swapping out the 350 in the K5 for a stroked 454. Part of it will be a tranny swap from 700r4 to a built TH400. The motor/trans are coming out of a drag car so the stall speed is pretty high on the converter (3500ish). From what I've read, finding the right stall speed is a bit of an art so I need some guidance. Here is what i think will be the pertinent information:

Tire diameter is 37"
final gear ratio of trans is 1:1
rear end ratio is open for suggestions, probably 4.56 or 4.88
HP at the crank 800+
Driving habit / use of truck: mud/sand, no crawling and of course hauling major a$$ off the line. dont care about interstate speeds. just want to play in the sand box and smoke some punks off the line.

Links or any guidance is greatly appreciated. Haven't started turning the wrenches yet but want to plan everything out as best I can. Thanks guys!

 

[1985_K5_Silverado]

That 3500 stall is likely to work well with the current cam profile in that BBC. What cam do they have in the engine? Looking at a HP/TQ curve for it might tell you a lot about which stall speed would be a good match.

 

[SkysTheLimit]

I dont have the specs on the cam handy, i'll have to get the nitty gritty details. It's pretty aggressive. the engine has a really nice sounding lopey idle to it.

On a side note, is a 14bolt / D60 combo strong enough to handle that much power? It'd be tough to smoke 4 37" tires but it sure would be fun to try...

thanks all!

 

[wayne]

800hp????????? It is probably a roller motor with that kind of number. Anyhow my guess it is probably stalling higher then 3500rpm. I would think more toward 4500. With that much power 4:56's will be fine. You could probably get away with 4:10's. A D60 and 14ff will be ok offroad in sand and mud but attempting the 4wd burnouts might hurt the D60's shafts. You didn't mention a t case but I would guess your planning for a 205.

 

[Chevy305]

Dude once you get it together you have to make a video of a burnout so you can compare it to BrandonC's videos.

Let me just say, 800hp

 

[SkysTheLimit]

The engine is a 454 bored & stroked to 496. Roller rockers, port & polish, balanced and all that jazz. I'm going to try my best to put together an article documenting the engine swap. I haven't had much luck finding one on the web. I'm going to start looking for 4.56 or 4.88 whichever I can find first/cheapest and go with that.

If I did a dyno run with the motor in the current car (ford 9" rear with 4.10) would that give an accurate enough HP/TQ curve to get me in the right ballpark for the stall speed I need in the K5?

Of course, for the group's benefit, before I do the axle swap, I will attempt a burnout and video it. No matter what happens, it will be entertaining.

 

[Chaddy]

On a side note, is a 14bolt / D60 combo strong enough to handle that much power? It'd be tough to smoke 4 37" tires but it sure would be fun to try...

thanks all!

Just make sure you have 300M shafts and CTM's or Longfield Joints in the front and you will be fine.