LS1 Donor car came with Moser M9 fabricated 9" rear. Resell or use for my 67 bird

[expensivehobby22]

Hey everyone, and thanks in advance.

Just picked up an LS1/T56 donor car for my 67 Firebird project, and it happened to also have a fabricated Moster M9 Ford 9" rear end. It's got 4.10 gears and a spool as well as the Midwest torque arm setup for 4th gen f-bodies. The question is, should I chop all the 4th gen brackets off and use this for my car or just resell? On one hand, it seems like a shame to do so and probably will be a pain in the ass, but on the other, I can't build a similar setup for anywhere near what I effectively got this for. I know that the 4th gen axle is wider. Anyway, curious about more experienced people's thoughts.

I already have all of the Ridetech 4-link parts with weld on lower axle brackets for my Firebird, and the car currently has a 10 bolt 8.5" rear end that I planned on refreshing/upgrading for my needs. Plans for the car are lots of spirited driving with some autocross and track days. Not really the drag racing type, at least at this point.

Thanks again,
Ray

[Build-It-Break-It]

The 4:10 gears and spool would be useless for street driving and any Autocross course. I would try and sell the complete set up and your 10 bolt and buy a Ford 9" set up for your car.

Do it once and do it right.

[TheJDMan]

Sell both the 10 bolt and the 9". Take that money and order the exact custom 9" you need from Moser. You will end up with the correct fit rear end for probably not much money once all is said and done. If you want you could keep the brakes and center section from the take out 9" and reuse them on the custom housing. Just one option. IMO, the worst case scenario would be to try and modify the take out 9". You will have a fair amount of time and money tied up in modifying the current 9" and will likely end up with a compromise rear axle when you're done.

[expensivehobby22]

Thanks for the input so far. Selling was the way I was leaning anyway. Though, I did forget to state that I would be changing the spool out for LSD if I kept the unit. Also, I will be keeping the brakes regardless.

Not to stray too far off topic, but you guys really hate the 8.5" 10 bolt that much? I've read a few articles that it can be pretty stout with a reasonable amount of money spent on it. I feel that I need to mention as well that, other than the ridetech stuff, the car is going to be a pretty low-buck, garage build. More ratty-muscle driver than anything that needs to look "perfect".

[astroracer]

Even IF you can build the 8.5 to be pretty stout, it will always be in the back of your mind... Sell it, get a Moser rear end and be done with it. Never have to worry about breaking the Moser piece. They are STOUT... :)
Mark

[qnitro]

sell me the rear end for my 91 Z28 build :)

[Z06vet]

I think you could sell that 9" rear pretty easily. And by the way, 4.10's are absolutely perfect with an LS1 F-body 6 speed. You can run almost every autocross in 2nd gear, and only turn around 2100rpm @ 80 mph.

[expensivehobby22]

Thanks for all the input guys. I have a local buyer already lined up!

[Rhino]

Not to stray too far off topic, but you guys really hate the 8.5" 10 bolt that much? I've read a few articles that it can be pretty stout with a reasonable amount of money spent on it. I feel that I need to mention as well that, other than the ridetech stuff, the car is going to be a pretty low-buck, garage build. More ratty-muscle driver than anything that needs to look "perfect".

Absolutely correct. the 8.5" can be built up well with a modest investment.
You mention the car is going to be more of a ratty-muscle driver than anything. The key phrase for me here is driver. If you're not planning on running in high load situations (eg: track launches on drag radials) then the 8.5" will be perfectly happy. If you do, make sure to properly preload the rear. It's the sudden jolt of the driveline slack that generally kills a rear end.

[minendrews68]

Take heed to all of the above recommendations. They sound like really good ones to me. I would see what I could get out of my old stuff and see what a new rearend would be. I would then weigh the difference if you feel like the difference is worth it or not.

[expensivehobby22]

Thanks again everyone for the good advice. I appreciate it. I've gone ahead and already sold the Moser.

Cheers,
Ray

[MonzaRacer]

8.5, lsd/gears/axles/c clip elim kit and preload rear cover. Should live on smaller slick easy. One of the older 10.5 drag teams used 10 bolt, stood car on rear bumper repeatedly on sticky tracks and had zero issues.
9" eats power UNLESS you use one of the center sections set up to use 12 bolt ring and pinion.