Rear end HP question
Thread Starter
Racer
Joined: Jan 2008
Posts: 338
Likes: 0
Rear end HP question
I was wondering what the maximum HP a stock '77 auto trans and rear end could reasonably handle. I have a mild 427 and was thinking of adding a 100 HP shot of nitrous if no damage would result. Everything is in good working order and the engine was rebuilt about 5000 miles ago. Any thoughts would be greatly appreciated. Thanks!
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
This has been asked many times. I have seen them blow with a 400 HP motor and I have seen them survive with a 700 HP motor. Traction is what kills these rears. If you are running street tires with an auto you might be OK. Slicks and stick shift and drag racing forget it. You better beef up the components. The least you should do is out in solid ujoints. Keep going from there. It will find the weakest link for sure. 
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
This should be a sticky it's asked so many times. It depends on what kind of abuse the rear end is subjected to.
If you rev a 300HP motor to 5000RPM and dump the clutch with nice sticky wide slicks it you will probably be picking up parts and soaking up oil from from the start line.
If your street tires spin or you ease into it with a 600HP motor you will most likely be fine if everything is up to par back there. I put over 600HP through my crappy aluminum rear punkin ever tiime I take it out and it is stock and it has never been completely rebuilt.
Shock is what kills the parts behind the tranny
If you rev a 300HP motor to 5000RPM and dump the clutch with nice sticky wide slicks it you will probably be picking up parts and soaking up oil from from the start line.
If your street tires spin or you ease into it with a 600HP motor you will most likely be fine if everything is up to par back there. I put over 600HP through my crappy aluminum rear punkin ever tiime I take it out and it is stock and it has never been completely rebuilt.
Shock is what kills the parts behind the tranny
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Thread Starter
Racer
Joined: Jan 2008
Posts: 338
Likes: 0
Thanks for the info. I am going to run street tires and don't plan on taking this car to the drag strip any time soon. I would be adding nitrous just as something to tinker with. I'm not sure how much HP I am running now, but I'm sure its far below anything I would estimate, so I was thinking running a 100-150 HP shot would not really put me over the top as long as there is minimal "shock"
