I am about to have the rearend rebuilt and I am undecided on the ratio I want to use. The car is going back pretty much totally back to original as far as the engine (302) tranny (M-22) and 15" wheels and tires, but I want more get up and go out of the car. The car will mainly be for cruising and shows and under right circumstances raced if you know what I mean. Here is what I have. The rearend is dated correct for the car and stamped for 3:73 gears. I definately want more than that. I have a very good set of 4:10 (aftermarket) gears but I'm leaning toward a set of 4:56. The car will have the original exhaust and smog pump setup. No power steering. I guess I am asking for opinions from other Z owners with basically the same setup. Anyone with a 4:10 and wish it was more and why? Anyone with a 4:56 and wanted less and why? I'm not worried about the extra fuel consumpsion and the cost of buying the 4:56 setup. Thanks for any opinions. Craig

Almost all the Z owners I know that cruise their cars have gone back to 3.73:1 gears after trying 4.10:1 or 4.56:1's. I think they get a bit gun shy over the high rpms after sinking lots of money into correct parts for their 302's. My personal feeling is if you plan serious track time start with the 4.10's you have and see how far you personally push the mill before stepping up to 4.56's... But if your gonna run street tires stay with the 3.73's

My car has the M-21 3.73 combo. The car is a dog in first gear but then comes alive with the close ratio box. It will bog with a 4K launch on street tires. The car runs 2.4 sec sixty foot times with a 104 mph trap speed - that's leaving a lot on the table in the first 60 ft. If you plan to drag race or just putt around on city streets, more gear is the way to go. If you drive on the highway (even occasionally) or drive to shows or the track, more than 3.73 will be miserable. It boils down to priorities. My car spends 95% of it's life in 1st/2nd gear on local streets, therefore I am considering either a Tremec swap or a 4.56+ rear gear. If I go the rear gear route, I will give up the ability to drive on the highway - too many rpms for my tastes.

Znut,

I have got the best of both worlds after a good buddy planted an idea in my head. I went with the stock BU coded 373 gears in mine which would have been fine. Then I added a crossram which likes more gear. I love high revs in town, but not when i'm on the highway, so he suggested rebuilding my M22 with a wide ratio aftermarket gear.

I have since bought the wide ratio M22 gears from Auto Gear (Italian Gears from Antonio Maseiro) and an M22 supercase. In the next few weeks we will have rebuilt the trans with this gear set and it will effectively give me a combined gear ratio of 438:1 when in first second and third. As soon as I hit 4th which is direct, the revs will drop back down to what 373 would produce and give me highway cruising at a decent rpm.

This is a nice way to come up with quick revs in the first few gears yet stil have cruisability at 65mph. Look into it. Its the best of both worlds.

Thanks for the info. The M-22 is at the tranny shop right now so it may be too late for the the change on that. I think I am going to go with the 4:56. The only close car show that is out of town is about ten minutes away so I think I can deal with it on the road for that long. Anything further I'll have to trailer it anyway. We have many shows in town that I can go to, which driving around town will be fine. How much is that gear swap for the tranny?

The new gear set sells for 595.00 US and includes 1st, 2nd, 3rd, 4th, the input shaft and the reverse idler gears. Aside from Synchro's, gaskets and some misc parts, that is the bulk of your rebuild depending on your transmissions existing condition. If you want to buy the gearset, there is a guy that lists M22's in the TC Classifieds sections (Tom at T&B Transmission)and is located in Spokane Washington. He can drop ship the gears anywhere and is really decent to deal with. I would also mention that you should look at their SuperCase bodies. This replaces the 660 main case and has a reinforced support and iron mid plate to reduce the chances of case failure due to flex in the gear mesh. Chances are you will end up paying for a rebuild anyways where your trans shop might just use generic gear parts and charge you as much as this new set costs. I say that because most Muncies that are 30+ years old are already thrashed and can cost big $$$ to rebuild. Once you have this gearset, the rest of the parts become trivial. Which ever way you decide to goe, good luck with your project and enjoy your summer cruising.

Graeme