how much hp can a built 8" rear

gonna build a motor hoping for between 400 and 500 horsepower (393 stroker) and i have a stock open 8" rear that im sure will blow sky high and it's 4 lug...lol. so what would be my best bang for my buck on a rear end

 

I'd go with a 9" if I was planning that much HP.

 

^Ditto^

Also go with 5 lug axles front and back and disc brakes in front for sure.

You might want to think about increasing the 9 inch rear brake shoes to 2-1/4" wide. Need drums and backing plates, common on Ranchero and wagons, but you have to double check.

 

i'm not afraid to push the boundaries.......I'll be pushing 380 plus at the rear wheels all motor with an ALumin8 center section from currie and dutchman axles,arp hardware.....add some NOS and we will see what happens....then again my car will be lighter than most......I *think* it will hold up!!!and if it doesn't it's only money and some time but if it does I get a few tenths shaved off the 1/4 and more on the road race track!!!

 

if you are going to use a sticky tire like drag radials or slicks then you need to upgrade to a stronger diff. if you will stay on street tires then the 8" should be fine. you can go with 9" or an 8.8. there are different sources for both those diffs and they both have discussed on this board alot. try the search feature.

 

You install any Alumin8 center sections yet? Mine is really nice the machine work is top notch....glad 8 and 9 are sop easy to set up!!!!

 

True.....my car will see more open track time where launches are not so important....my father ran 8 inches behind bigblocks when he raced for ford in th mid 70's for Ford.....ran mostly fairlanes with 427/'or 428 behind 4 speeds....believe it or not they held up more often than not....he blew one or two out over a couple seasons.....he had a guy debur everything and I think shot peen the whole hogs head( ill ask him next time I see him) and ran top notch bolts that where at the time custom made....it gained him .3 tenths or .4 tenths in the 1320!!!I think many poeple under rate the 8 since in proce terms they are more costly to build for High Hp than say a 9 or even an 8.8 these days. My old combo put 300hp to the rear wheels give or take 10 hp and it held up fine!!!nothing special and stock axles....but past that on a drag only car i can see your point

 

i have not goten my hands on one yet. i would like to. the 8" uses 3/8s cap bolts where the 9" uses 7/16 cap bolts. if i was trying to give an 8" the best chance of survival i would put 7/16s cap bolts in. does the alumin8 still use 3/8s bolts?
deburing definitly helps. if you could get a billet steel cap for the rign gear side would be a good upgrade also.

 

My stock 8" ('cept for mini spool) lived behind about 400 hp, leaving on 150 shot NOS on sticky "street" tires, for about 6 years before laying down. But it wasn't the center that failed, it was the right axle tube that bent. Having said that, if you gotta swap it out anyway, go for the 9". I just used what was already there 'cause I'm cheap.

 

Description: Alumin8® aluminum 8" Ford gear cases are a 100% new piece cast by Currie out of 206T6 aluminum. Cases may be polished to a show quality shine. This case is much stronger than stock but it is still not recommended for abusive or race applications. Weight is just 10 pounds! Additional features are 1/2"-20 x 3" long carrier cap bolts as opposed to the 7/16"-13 x 2" bolts that were featured in stock 8" 3rd. members.


weight is a key factor in every piece I choose!!!!


There is a guy running one in a falcon down this way 289 4 speed car runs mid 11s or so last i heard no issues.....but I still agree with the 9 inch for drag only cars IMHO....thats why lil bros car has a nodular 9 inch detroit locker 3.70 w/31 spline mosers.....331 with a 200 shot of the sauce

 

ah ok. i had the bolt sizes wrong. gota love when they make something stronger but recomend against racing with it.

 

Here is what someone else did to remedy his problem of destroying 8" rears. Assuming you have an original 72 8", you wont have the problem of smaller axles and weaker case, but what he did I have to believe was a major improvement over stock. Some assembly required...
http://tffn.net/phpBB3/viewtopic.php?f=11&t=15709&hilit=center