need advice for 71 demon

Posted By: dughuff

need advice for 71 demon - 07/25/10 11:48 PM

I'm swapping out the slant 6, 3 spd manual for a 360 and 4 spd. I've got someone who wants to sell me an 8 1/4 sure grip rear end but wonder if its strong enough. Should I be spending my mony on 8 3/4? Thanks for your help

Posted By: okie

Re: need advice for 71 demon - 07/26/10 12:01 AM

I would go with the 8 3/4, you won't regret it down the road. Ronnie

Posted By: nomore65BelvJim

Re: need advice for 71 demon - 07/26/10 06:05 AM

8-1/4's are all large bolt pattern so unless your upgrading the front to large bolt pattern 73+ A or F,M,J discs you'll need two spares

The 8-1/4 can handle a fair amount of torque/HP. I guess it depends on what your HP goals are.

Posted By: Hotwheelsjr

Re: need advice for 71 demon - 07/26/10 06:15 AM

I've been running an 8.25 for 20 years in my 400hp Demon -- have another one in the backyard that I plan on swapping in (has 4.10s in it

). I also have a 8.75, but don't have BBP axles for it yet. I wouldn't worry too much if you don't plan on throwing 450+hp at it. Just my

Posted By: RapidRobert

Re: need advice for 71 demon - 07/26/10 06:22 AM

Quote:

but wonder if its strong enough.

yes but you're stuck w it's ratio after you change it so get the right ratio that you'll be happy with forever but with that being said I'm with Okie, I like the drop out convenience of an 83/4 and the axle end play adjustment just cause I'm used to working with it. EDIT send a 1/2T truck/C body or B or E (either the B or the E is too short, forget which one) housing/axles to Moser for shortening (cheap/easy) and dont forget to have them switch the perches to the bottom (if it's a truck housing). That'll get you the BBP and oe A body 8&3/4's are getting pricey/scarce and have SBP

Posted By: 340SHORTY

Re: need advice for 71 demon - 07/26/10 08:12 AM

the 8.25 was the performance axle in the 340/360 A body cars from 73 and up.

Posted By: nomore65BelvJim

Re: need advice for 71 demon - 07/26/10 08:59 AM

last year for the A body 8-3/4 was 72. It was 7-1/4's and 8-1/4's from 73 on.

Posted By: ademon

Re: need advice for 71 demon - 07/26/10 01:34 PM

i would hold out for a 8.75.

Posted By: Paul_Fancsali

Re: need advice for 71 demon - 07/26/10 02:21 PM

I finally after 18 years switched out a 8.25 for a 8.75. I broke the spiders gears on it using a set of 11 inch drag radials That is over 1000 passes and 20+ k of street miles. A 8.25 is good enough if you have deep enough gears a min of 3.21s with a 4 spd unless it is deep low trans.I'm all for the 8.75 but use what you have if it saves you money. Besides most 8.75center sections are like gold when you look at the prices in the used parts due to high cost of sure grip