I have a 87 camaro with 10 bolt differential with a a Ratio 2.75

[jbander]

I want a 4.11 or 4.56 Ring and Pinion. It has 28" dia. tires on the back. Some of the lower ratios on this differential 4.11 and 4.56 ,says that it will only go in a 3.23 or higher case. My ration is 2.75 so does that mean I can't put these lower gear ratio in my car or should I be looking at other Ring and Pinion sets.Or am I misunderstanding the whole thing.

[ariZona28]

My Father's hobby car is a '85 Z28. Faced with the same dilemma he opted to replace the entire diff assembly with a complete 3.73 12 bolt unit he purchased from Moser. His 383 makes 425 HP and 400 TQ. Money well spent. That original rear is fairly weak. I do believe it's a 7.5" leftover from the Monza.

[KJZ28]

Originally Posted by ariZona28

My Father's hobby car is a '85 Z28. Faced with the same dilemma he opted to replace the entire diff assembly with a complete 3.73 12 bolt unit he purchased from Moser. His 383 makes 425 HP and 400 TQ. Money well spent. That original rear is fairly weak. I do believe it's a 7.5" leftover from the Monza.

Some guys on thidgen.org put axle tube braces on the 10 bolt, makes them handle 500-600HP. I remember one guy who went that route because he road races and when he went to a 12 bolt, the added weight negatively affected the handling. He went back to the 10 bolt.

[ariZona28]

When OP says 28" tires and 4.56 gears that looks to me like drag race, smokey burnout desires. By the time you beef up the dainty little 10 bolt and find some gears (if any are made for that particular rear) your cost will probably exceed a nice, easy, bolt in unit from Moser. They're even available with disc brakes.

[jbander]

Well, I'm not concerned about burning rubber or hole shots and I'm not going to a drag strip but I do like speed. My thoughts now to start with is getting a 4.56 thick ring and pinion that will fit in my type 2 differential. Any thoughts . A different differential is in my future but not now.

[ariZona28]

Sorry, I forgot to ask my standard questions: What engine, trans, and mileage on drivetrain? Suspension mods? Sub-frame connectors? What are your intentions? Weekend warrior or daily driver? From my limited experience with your orig diff they don't last very long after moderate HP increases especially if they have logged a lot of miles. A quick note, I just did a Google Search and found a company named Randy's Worldwide. They have several gearsets for your diff. Give them a call and see what they say. Nice thing about '80s Camaros is that everything has been done to them by someone. You're not the first guy to overcome this obstacle.

[jbander]

Originally Posted by ariZona28

Sorry, I forgot to ask my standard questions: What engine, trans, and mileage on drivetrain? Suspension mods? Sub-frame connectors? What are your intentions? Weekend warrior or daily driver? From my limited experience with your orig diff they don't last very long after moderate HP increases especially if they have logged a lot of miles. A quick note, I just did a Google Search and found a company named Randy's Worldwide. They have several gearsets for your diff. Give them a call and see what they say. Nice thing about '80s Camaros is that everything has been done to them by someone. You're not the first guy to overcome this obstacle.

355, lightened steel crank, lighted rods, light weight short skirts pistons, all balanced, 2.02 heads, stainless
valves, spring pockets cut for larger diameter springs and height matched for proper springs, 301 duration
linati cam 2800 miles Trans is a 700 r4 with new upgraded steels and clutches, shift kit, 2800-3000 stall
all with less the 500 miles Sorry forgot 10.5:1 compression, all machine work was done by R&S Racing
in Albert Lea, MN Motor was built to handle a 200 shot of nos but has never had it, it was in my dads 35
ford coupe but he decided to go a different route

Yes very, pump gas no pinging no weird shakes or rattles, it was built with a ton of power but hop in and
drive it anywhere, like I said it was in my dads street rod, 1200 of the 2800 miles come from there run to
Branson, and a few trips to back to the 50s in St. Paul. Never runs hot and great on the freeway, the only
reason my dad changed is he went to a 711 hp 383
2800 miles on the build, longest trip was about 550 miles each way, absolutely no overheating even on
the hottest days, yes you could drive it home if you want but I would trailer if possible in this weather but
up to you
GM steel crank and rods, arp main and rod bolts, comp cams hardened.080 pushrods, melling pump, je
pistons, comp cams roller rockers, comp cams true roller timing chain, not sure on the brand of converter
but I have the box at the shop, b&m clutches and steels and shift kit, seal power rings and bearings
GM bow tie heads
I have a entire box of info and lists on the car all the way back to when it was owned in California, heat
yes, cam 301 580 lift, heads are gm bow tie 2.02 1.60 manly stainless valves exhaust is new, done by a
shop here in Northwood, not sure how much more info there is that I haven’t already given, trust me you
will not be disappointed

Don’t have cam box for part number nor piston box, heads are gm bow tie heads, don’t have the boxes but
if you search them you will see what I’m talking about, only thing done to them is manly swirl polish
valves and spring seats cut for bigger diameter springs and springs installed with titanium keepers, Holley
750 double pumper street fighter, new hooker long tube headers, new full 2 1/2 exhaust, yes it does have
the stock 10 bolt and not sure what that gear ratio is.
He doesn’t keep anything un like me, they are the double hump style, I just talk to him and he said they
are the better out off all of them 194 runners and 58cc
They are Firestone FR710 215/65R15 95T M~S So a very good all weather tire
SRL series 9.5” billet 3200 lockup converter
My intentions don't include drag strips or even street combat, I like fast and it doesn't have to be out of the hole. It turns out that the project itself has become as interesting and exiting as the ride. I'm enjoying the build.

[jbander]

Originally Posted by ariZona28

Sorry, I forgot to ask my standard questions: What engine, trans, and mileage on drivetrain? Suspension mods? Sub-frame connectors? What are your intentions? Weekend warrior or daily driver? From my limited experience with your orig diff they don't last very long after moderate HP increases especially if they have logged a lot of miles. A quick note, I just did a Google Search and found a company named Randy's Worldwide. They have several gearsets for your diff. Give them a call and see what they say. Nice thing about '80s Camaros is that everything has been done to them by someone. You're not the first guy to overcome this obstacle.

Do you have anything to add about using a thick ring and pinion so I don't have to change carriers from a type 2 to 3

[ariZona28]

Wow, that sounds like a fantastic build! It seems like you've put a lot of time and $$$ into the engine/trans department why compromise on the rear diff? Sure, you may be able to get a good ring and pinion set but the other pieces such as bearings and axles will eventually need attention. Is it a Posi and if so what shape are the clutch packs in after 30 years? If there's any weak link back there it will fail at the wrong time. Throw in the cost of bearings, axles, Posi rebuild and labor (yours or a shop) and the $$$ adds up quickly. Maybe see if you can scrounge up a used rear either at a swap meet or even on the internet but that is always a "buyer beware" situation. And I'm sorry but with a kick-ass 355 and 4.56 gears there is no way you're not smoking those tires on occasion!

[jbander]

Originally Posted by ariZona28

Wow, that sounds like a fantastic build! It seems like you've put a lot of time and $$$ into the engine/trans department why compromise on the rear diff? Sure, you may be able to get a good ring and pinion set but the other pieces such as bearings and axles will eventually need attention. Is it a Posi and if so what shape are the clutch packs in after 30 years? If there's any weak link back there it will fail at the wrong time. Throw in the cost of bearings, axles, Posi rebuild and labor (yours or a shop) and the $$$ adds up quickly. Maybe see if you can scrounge up a used rear either at a swap meet or even on the internet but that is always a "buyer beware" situation. And I'm sorry but with a kick-ass 355 and 4.56 gears there is no way you're not smoking those tires on occasion!

Thanks for the response. I agree but it isn't going to happen for a while. Every rear end I've looked at has been out of my price range for now. But I can go the thick 4.56 route with my 28" tires it will be the same as about a 4.20 Then I don't have to replace my type 2 Carrier. I've been asking around about these thick ring gears and not getting a lot of response.

[ariZona28]

Unfortunately I'm not familiar with the thick gearsets you're contemplating. Be sure to enquire as to the country of manufacture as quite often Chinese parts are made "thicker" to compensate for inferior quality materials. I'm thinking if you do go the more budget friendly route you could install the 4.56s, maybe install new axle bearings and provided you exercise some right foot discipline this could hold you over until you get the cash for a stouter diff. You could then sell this rear to help replenish your wallet. I reviewed your other posts and you did go pretty meaty with those back skins! I'd love to see a picture.