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I've researched previous threads on rearend questions and now I'm ready to upgrade my '87's rearend for a couple of reasons. First it is still poor out of the hole, and secondly, I've decided to replace the TH350 with a 700R4 so I can still get some benefit of an overdrive unit when I have to drive a couple hundred miles to car shows. Currently, I've got a strong crate 350 HO Deluxe in the Elky, but it's got the puny 2.41 rearend in a 10-bolt posi unit.

From the previous threads I gather that I want an 86-88 Monte Carlo SS posi rearend for the benefit of the 3.73 final gear.

If I were to find someone that would part with only the ring & pinion from an 86-88 MCSS posi unit, could I buy those and place in my current housing? Can I buy any GM 7.5 10-bolt R&P, say on E-bay, and use those in my current housing?

Thanks for any info.
-dan
 

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ElkySS said:
...it's got the puny 2.41 rearend in a 10-bolt posi unit.
Since you already have a good posi unit just get a set of 3.73 Richmond gears for a 7.5" series 2 carrier. Summit has them.

http://store.summitracing.com/partdetail.asp?part=RMG-4900071

Swap the Richmond 3.73 ring and pinion into the existing posi carrier and you've got the equivilent of a Monte Carlo SS rear end.

:mrgreen:
 

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ElkySS said:
If I were to find someone that would part with only the ring & pinion from an 86-88 MCSS posi unit, could I buy those and place in my current housing?
Dan, I forgot to mention:

No, you can't put a MCSS 3.73 ring and pinion into your carrier. The 7.5" rear ends have both a series 2 and series 3 carriers. Series 2 is 3.08 and numerically lower. Series 3 is anything above 3.08 gears. Series 3 ring and pinion won't fit in a series 2 carrier.

:mrgreen:
 

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FOR DAN-YOU'RE GONNA LOVE THAT 700R4 (GET 1 '88 OR NEWER),+ HAVE THAT TV CABLE ADJUSTED BY A KNOWLEDGEABLE TECH.IT'S EASY ONCE YOU KNOW HOW.THE 700R4 REALLY GAVE MY '79 SOME "LEGS"
 

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Dan im going to put a 342 monte carlo ring and pinion in a 229 2 series possi 10 bolt all you need to do is buy a spacer that fits behind the ring gear it s $75.00 cdn and then you can put your 373 3 series monte gears on to your 2 series possi. thats what my friend that builds race car rear ends told me.and Dan that set up with the 700r4 should work pretty good.
 

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Here are some things I learned recently. Take it for what it is worth. The 200R4 is actually a better 1-2 and 3-4 combo than the 700R4 and the final drive is .63 not .70 like the 700R4. Also the 200R4 is the same length as the turbo 350 meaning you can use your drive shaft. Still have to fool with the cross member it is still an overdrive. Both are rated from factory at 350 Lb.Ft. of torque and I believe that the 200 series overdrive actually absorbs less of the horse power, over all, giving you more at the wheels.


If you went with either you could and I did with the 80, use the Richmond 4:10s for the 3.08 and Numerically lower carrier. Still your RPM at 60 would be at or close to 2200 to 2500. I didn't do the math tonight but I did it on my 80 with just that combo (700R4 & 4.10:1 Rear) and top speed (6500 RPM) was somewhere around 140 or 160 on paper. The 200 series would be slightly faster because of the final drive being .63 and in turn at 60 slightly lower RPMs. (Hell, who drives 60? :lol: )

If your going for the gusto then do it big. 4.10 is much better out of the hole and you could probably just start in 2nd with those gears.

Think about it. :cool:
 

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Discussion Starter #7
Guys,
Thanks for the very good input. I didn't know anything about different "carriers". I opted for a new Richmand 3.73 R&P for series 2 carriers. Found a new one on e-bay for $130.
I'll let you know of the difference when I'm done with the whole swap. May just put the R&P in first to see what it does with the TH350 in place.
 

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The carrier is what the Ring Gear Mount on. There are Posi types, Open types, Lockers etc...

The carrier has a bearing on either side and is held in place by Caps much like the ones on the Main Bearings only these are roller bearings. Be sure while removing the carrier and gears that you mark those caps for side and position before you remove them. They must go back on the same place and way they came off.

May I recommend a Richmond Master Rebuild kit? It has all the necessary replacement bearings, seals, gaskets, shims, crush washer, new bolts etc... Everything you'll need to finish the rebuild.

If your doing OD tranny go for 4:10s.

Just input.
 

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Discussion Starter #9
Thanks, Pete.
 

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so....
how does one tell a 2 series from a 3 series rear end ?
1980 ElCmino 229 V-6 350 turbo ( it replaced the 200metric)
 

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so....
how does one tell a 2 series from a 3 series rear end ?
1980 ElCmino 229 V-6 350 turbo ( it replaced the 200metric)
Even 12 years later it is a series 2 or 3 carrier in the rear end, not a series 2 or 3 rear end. Yours can only be a series 2 if original 5th Gen and will only work with the OE gears between 2.41 and 3.08 whether open or posi.

From post #3 above The 7.5" rear ends have both a series 2 and series 3 carriers. Series 2 is 3.08 and numerically lower. Series 3 is anything above 3.08 gears. Series 3 ring and pinion won't fit in a series 2 carrier.

Also see here: http://www.elcaminocentral.com/showthread.php?t=33126
 

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so....
how does one tell a 2 series from a 3 series rear end ?
1980 ElCmino 229 V-6 350 turbo ( it replaced the 200metric)
Sometimes there is confusion with the '10 bolt' part. The 5th Gen 7.5" 10 bolt is not the same as earlier 2nd and 3rd Gen GM 10 bolt rears that were like 8.2". The carrier options on those was (I think?) a series 1 or 2 rather than 2 or 3.

Ya can't take the stuff out of an 8" or 8.5" rear from such as a BGN, 442, etc. and plug into your 7.5" 5th gen rear end. You can swap the whole rear end though.
 

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cornfused yet??
and now days they sell 3 series gears "thick gears" to fit a 2 series carrier,, and they sell spacers also..

the difference in the carrier is small, like a 1/4"inch offset where the ring gear bolts on..
3 series is 1/4" closer to the pinion, to make up for the smaller pinion..

:texas:
 
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