Well, I don't do drugs, but those of you that know me realize I sure act like it sometimes.. I get a hair brain thing in my mind, and get all crazy about....then after coming back down to earth realize that it really is not a big deal...so move on in a more sensible way... I have posted a lot recently on ways to get an OD into my '63 Biscayne, running a pretty *****y little 283, and rather than add more confusion to that thread, decided to just go with a fresh start. Currently running a Saginaw four speed with the 3.11 first gear, and THOUGHT I had a 3.36 rear end. Was told that when I bought it... My trans has had issues going from 2nd to 3rd gear for some time...had it taken apart, a few bearings put in and thought it was fixed...NOT...must be some syncro issues that they missed. Anyway, I now have now figured out that I really have a 3.56 rear end, which is still OK with me, but explains the higher RPM's running at ~60mph. I am tired of messing with this transmission so am buying a rebuilt 4 speed Saginaw...with guarantee, that has a 2.84 first gear and have decided to live with the higher rpm's an just stay off he interstates ... Sooooo with that long dissertation, finally my question: Anyone running this combo ?? And how do you like it. I don't think I will notice too much difference in the first gear change.. What you experts say? Thanks much.. OH, here is a table of the gear ratio's on the Saginaw's... TRANSMISSION 1ST 2ND 3RD 4TH Saginaw 4-speed 1st 2nd 3rd 4th No lines 2.84 2.01 1.35 1.00 1 Line 2.54 1.80 1.44 1.00 2 Lines 3.11 2.20 1.47 1.00 3 Lines 3.50 2.47 1.65 1.00
You may be able to tell the difference in 1st gear, but likely not. I asked my Quickchange mentor once, "How much of a gear change does it take before you can feel it?" He said, "About a quarter ratio." Now, this was a high powered late model pavement oval track car. And that is based on the point of the tires breaking loose. Let us know how it works out for you. PS I have a Saginaw 4 speed with 2.84 1st gear that I adapted the Borg Warner Overdrive from a Saginaw 3 speed. Haven't had a chance to drive it yet.
Well, I'm not an expert, and I'm not running that combination, but why should that stop me? With either the 3.11 1st or the 2.84 1st Sag., you're going to have the same final drive, so you know that as long as you're not trying to keep up w/ 80 mph traffic on the interstate, you're o.k. Years ago, before the T-5's got popular to use, I read in R&C or somewhere that for a stick trans, a 1st gear x rear end ratio of about 11.5 or 12:1 was the ticket to get moving fast; so a 3.0:1 first x 3.90:1 rear would give you an 11.7:1 gear to get moving in. Your old trans, w/ 3.11 x 3.56 rear, would start you moving w/ a 11.07:1 gear, not too bad. The 2.84 x 3.56 rear, will work out to 10.22, which gives you a little less mechanical advantage with this gear. I had put a GMC 302 in a '39 Chevy, maybe about the same weight as your car. It was not a high revving engine, but it had some torque down low. I was going to run a 3.11 1st Sag w/ a 3.08 Nova 10 bolt rear, for a 9.57:1 gear to start, but then I got a deal on a Muncie M-20, and I had to run that 'cuz its cooler, right? Well, with the 2.54 1st x 3.08 gave me a 7.82:1 gear to start, and I didn't like that combo at all. I'd have to slip the clutch just to get the dang car going. So, your combo w/ the rebuilt Sag may be a little slower to get moving, but its not really going to be radically different from what you've had. Hope this helps, K6.
It's too bad you didn't rebuild the Saginaw yourself, they are bone simple. When I rebuilt mine I replaced the synchros and she was hanging up and not shifting. I went to an old transmission shop and had a talk with a guy who said , "If the synchros look good, we replace the bearings and small parts but leave in the old synchros". I pulled her down again, replaced the new with the old synchros and 'Bob's your uncle' 2 years later 10 k miles on my dd/only vehicle. For the rebuild of the transmission I bought a beautiful set of snap ring pliers and a tub of transmission rebuild grease (worth it's weight in gold). AFA the here and now you've got a great trans, just be on the look-out for a higher ratio (lower numerically) rear end. You are really good to go. BTW, I have the 2.84 no ring Saginaw, not a stump puller and not a 'I think I'll start out in 2nd gear'. Although I have a 3.90 rear, I have tall tires at 30.5 inches. I think you'll find you set up very sound, and then when the rear end appears you can achieve even better fuel mileage. Remember, taller tires are 'the poor man's overdrive'.
Wow, thanks for all the replies...I am encouraged. And FYI I am running 245-60-14 tires on the rear, which are 25.57" tall.... I think I am going to like this combo... My car is a driver/cruiser...don't race it as being a (71) year old Senior, I can't afford to break it. Never ever have dropped the clutch in first gear, and not a posi...but do like to take off normal and then get on it at about 2500 rpms, which is where my old style L79 cam likes to kick in..stomp it then and when I hit 2nd gear quick shift (not speed shift) and a nice respectable squawk out of tires make me smile a lot !! My 283 is also bored out .60 with HO 202 heads, full 2 1/2" Corvette Ram Horn exhaust all the way back, and a few other things...runs pretty much like the old stock 327 (300) hp engines... I will update this thread when I get the ****** swap done..
If 3.56 rear gears are too much rpm for cruising , well you'll not be changing that. Your 283 should be loving that though. The gears are multipliers of torque and since gears are rotational they have a direct relation to engine rpm and road speed. Your mission should you accept it - is to develop the most torque and get it to the pavement while remaining within the acceptable speed limits. Is the limits 65 or 120 you decide. Engine torque x first gear ratio x rear gear ratio / tire radius in feet 100 ftlbs x 3.11 x 3.56 = 1107 ft lbs at axle flange / 1.08 = 1025 ft lbs at road 100 ftlbs X 2.84 x 3.56 = 1011 ft lbs at axle flange / 1.08 = 936 ft lbs at road From your specs I'd say that engine loves to rev and you should drive it like that and not worry . in the lower rpms it's not developing as much torque vs higher rpms.
I would be doing this http://www.hotrod.com/how-to/transmission-drivetrain/1403-get-gone-gr***roots-overdrive/
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