driveline HP limits?

[PA Dodger]

I'm tossing around the idea of a stroker engine like many others here are. It seems that these stroker engines can easily make enough HP/torque to trash everything connected to it. Generally speaking, at what point am I going to scatter my transmission and-or 8 3/4 rear? I hear 600hp is about it for an 8 3/4 rear, correct? I have no clue on a 727 BB trans though. I've seen Vegasmikes and Magnum 471's buildups and am impressed, but not if its at the expense of a Dana 60 rear etc...

Dan 

[Mike DC]

 
Unfortunately there isn't any clear-cut HP numbers ratio to go by. 

The vehicle weight and the size/grip of the rear tires have every bit as much to do with the issue as the HP levels.
And stick-shifted cars will stress everything harder than automatic cars in general.  (Not counting drag-only setups like transbrakes or something.)

A higher-quality rebuild will change things a lot even among any one single model of axle.  Most of the popular rearends can take aftermarket ring/pinion setups with better-grade steel, and better bearings, axleshafts, etc.

-----------------------------------------------------------------------------------

If you're talking about an automatic tranny, 15x8" rims with street radial tires?  Then the factory 8.75" rearends are pretty darn good even for a lot of horsepower.
 
The Dana 60 is more like the "nuclear option."  It's about 50lbs heavier than an 8.75" rearend (and that's UNSPRUNG weight), but all that weight is in the right places. 
It's overkill for just about anything that's still shaped like passenger car.

 

[PA Dodger]

Yeah, I'm talking about a "mostly-street" car, but you don't build a 550-600hp engine not to have some fun now and then. A Charger goes about 3800 pounds and I have thought about mini-tubbing the car, but no slicks. I've seen transmission companies that say "up to 600HP".  I sure wouldn't want a full race trans in my car, but I also don't want to gernade the trans or rear either.

Dan

[firefighter3931]

Dan, the 8 3/4 will live as long as it doesn't dead hook. Slicks with a lot of torque (stroker) is the deal breaker for 8 3/4 3rd members. 

As for the trans ; a good quality rebuild with HD clutches and bands is fine for the street and light strip use. A deep pan and trans cooler are basic requirements at that power level along with a good quality torque converter.

I would also look at upgrading the valvebody....Turbo Action makes a nice "pro-street" foward pattern VB with low band apply. Vegas Mike has that one in his car and i have the same unit going in mine. 



Ron

[Ghoste]

That's a manual valvebody, correct?

[firefighter3931]

That's a manual valvebody, correct?

Yep, it's a forward pattern manual valve body. TA also makes a manual/auto VB as well.




Ron

[PA Dodger]

Thanks guys. I was looking at the 440 Source stroker kits. Since all the kits are the same price it's real tempting to go wwaaayyyyy too big! I was reading back-issues of Mopar Action on their 496 stroker buildup. Looks like a sweet buildup if not a little overkill. I already have the professionally built trans with cooler. And was looking at Moser axles to replace the 38 year old axles. I'll have to check into that valve body.

Dan   

[MOPARHOUND!]

The life and times of a 496 stroker owner, 100% street driven, never raced:

http://www.cuda-challenger.com/cc/index.php?topic=19349.0

I have a stock 727 behind it, and it has held up, no problems -  I believe due to not enough traction to jolt the trans or the 8-3/4 rear.  Have a '71 Dana 60 built for it, but have never had nor felt the need to install it.

I believe the 4.25 crank can fit in a 440 block and retain the stock oil pick-up???  I know mine still has it with the 4.15 stroke crank. 

If I build another, it will have a 4.50" crank, with the single external line setup, more $$ but what the heck.  I think Indy sells the single line setups, and another company (Milodon or Moroso??).

[Chryco Psycho]

basically as long as the tires spin you wil not break the 8 3/4 , get traction & kiss the diff good bye

[Challenger340]

All the problems I had with the 8 3/4 rears, was basically attributable to "shock" loads, no "shockload", no blowing the caps off the diff.

Aftermarket axles from strange, ditch the transbrake, and I could "footlaunch" the thing @ 2500 rpm to 10.1's at 135 mph.(4500 ft. baro elevation).
I was much happier being able to drive it home, after driving TO the track, without calling a tow truck.  LOL !

"TRIVIA" From a guy thats blown a coupla dozen 8 3/4's, just my opinion,
The 742 cases are actually a little stronger cap, due to the better broaching around the cap bolts. Some early ones are actually "pretty" in there.

The 489's are sharper around the cap bolt, and more succeptible to breakage, almost "break on dotted line",
even though the pinion is heavier on the 489.

What worked for me, was a 742 case, strange axles W/green brg's. Dunno if thats a good ticket for sustained street, but it worked for me.
Bob out.