727 Trans question
 

I am am getting finished with the body and paint work on my 72 challenger. I am putting a 440 source 507 in this car with the parts I am using they say it should make 550-600 hp at the crank. The guy building my trans says I need to put a billet direct drive drum in the trans to handle the hp. He says that over 500 hp you need to put the billet drum in to keep the trans from exploding. I trust the guy but I think he may be being over cautious at my expense. What do you guys think billet or not?

Never heard that before, but then again I usually have a good friend build all my trannies for me.

All I can remember is that if your "sprag" breaks at elevated rpm's, there's a good chance the direct drum might go with it.The original drums come apart at high rpms.This happens when the sprag breaks because the drum start turning twice as fast as the motor when that happens. If you put a good bolt in sprag in the trans and are very careful doing burnouts[key] then having a billet drum would just be good insurance. Of course, being made out of aluminum, it would also reduce your rotating mass. Put a goog sprag in and then learn how "not to break it" is what I would do.....{but then again, I'm cheap, that drum gotta be high dollar}.

The plan was to use a billet steel drum because of the wear issues with the aluminum drum in a mostly street driven application so no weight savings. the added cost is about $700 for the billet drum I just don't want to trip over dollars to pick up dimes you know save $700 and loose a foot or even worse damage my car I can always get another foot https://moparforums.com/forums/images/icons/icon10.gifhttps://moparforums.com/forums/images/icons/icon10.gif

sounds like your builder nows what hes talking about and if you have the x-tra funds go for it as it might be your foot u save <<>> but on the other hand i have never had a problem with one breaking :)

I agree if you can afford the extra 700 it good insurance.............then again a Tranny scatter shield would be less$$$.$$....and it would save car, and leg....................Would not help much with the exploded tranny thow:D

I'm having the tranny built with all the goodies for $1,500 it should be done by next week. My dad always said better to have and not need than to need and not have. At least with this tranny I don't have to worry about it exploding when I'm beating the crap out of the car.