Hi all,
I remember various discussions about changing the ring and pinion in a Spicer rear axle as an alternative to using an overdrive gearbox. If i'm right Spicer axles are identical to Dana so using Dana 27 parts would be ok??
If so, is there anybody out there who has done a upgrade to 3,73 gears in a stock rear axle, not changing complete axles, just fitting these gears in a Spicer axle and if yes, where did You get the gears from? I checked several Jeep pages, but they use higher gears like 5,88:1

Thank you and best regards
Michael

First would be to make certain you have a Dana/Spicer 27.

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-Matt I ♥ my ♂

My vague notion is that B16 engined cars, usually with a 4.56 rear end, have an earlier axle that isn't a dana/Spiver (ENV?). The B18 engined cars got the stronger Spicer unit and taller 4.1 gearing.
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'63 PV544 rat rod, '93 Classic #1141 245 (now w/16V turbo)

My '58 444 has the Dana rear in it.

The ENV is very easy to identify, as it has no bolts or cover to remove on the rear part of the pumpkin, whereas the Dana does.

As noted, EVERY gear will be reduced, and will affect the overal driveability of the car.

An OD would be nice, but the idea of cutting up a perfectly good (rust-free) 444 to install one just isn't worth it to me. I'll take the back roads.

"Upgrading" as you call it to a 3.73 axle does give you a top, 4th, gear about the same as fitting an overdrive, 5th, gear. Problem is, the other 3 gears then in effect all jump up one giving you a 1st gear that's about the same as second is now. This doesn't work unless you're prepared to slip the clutch a lot getting moving and you also have LOTS more power to enable you to make the top gear usable at all times rather than having it as a cruising gear like the overdrive. You'd still find yourself running around in 3rd gear most of the time. Go M41. Yes it does need a bit of floor modification but it's well documented and works well.

I have gone the OD route and fitted a M41 to my car, running it with the 4,1 axle. No Problem with a B20 and 100 horses. But M41 are rare, expensive and the change is not that easy. So my friend, who has to rebuild his rear axle was wondering whether the change to 3,73 would be a viable thing to do. I know that you change all gears with that, using a M40 from a 73 140 gives you a shorter 1st gear so this should work fine.
Michael

We installed 3.54 rear end gears in a 544 for one of our customers with a healthy B18.

It was a little sluggish off the line, but it cruised very nicely at freeway speeds.

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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502

Eric: was that 3.54 installed in a dana 27 or a dana 30?
thanks
dean

We installed the 3.54 gear set in a Dana 27 and this did require changing the carrier housing.
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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502

Thanks Eric. Do you know of a supplier that still sells the parts for this conversion? I haven't found one

Dean

My supplier only sells to re sellers like me and does not deal with the general public.

I can call them and see if they have or can get what you want.

Which exact gear ratio do you need?
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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502

Thanks Eric. Do you know of a supplier that still sells the parts for this conversion? I haven't found one

Dean

Well, changing to 3.73 from 4.10, namely to 11:41 gear teeth from 10:41 gear teeth, produces a rev reduction on the road in every tranny gear in the ratio of 10 to 11, or only about 10 percent. An OD reduces top gear revs by lots more than that; same for the rev reduction with each upward gearshift.

Volvo was pretty good in non-OD cars to equip them to reach the best top speed at the engine rpm that produced the best power. That's why a 544 with the 85 hp @ 5500 rpm B16B usually had a 4.56 (9 to 41)axle and a 544 with 90hp @ 5,000 rpm B18D had a 10 to 41 to make about the same top speed.

What is the cost-to-satisfaction ratio in fitting new gears that give just a 10% rev drop?

I did an OD swap on my car. It's far from a trivial task, involving a lot of sheetmetal chopping and welding. But the results are more than worth it. My car, even with a 4.10 rear end in it, is practically undriveable on long interstate trips without the overdrive. The sustained high revs just sound abusive. perhaps it's actually OK to rev the pi55 out of it for hour after hour after hour, but it just doesn't feel right. Click on the OD, drop the revs way down, so incredibly nice.

My car has almost double the HP it originally had though, so no problems pushing a taller gear.
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'63 PV544 rat rod, '93 Classic #1141 245 (now w/16V turbo)