Inliners International Forums General Discussion Engines a 261 for my 40 sedan

It's been a while since I posted anything. My 40 twodoor sedan has been in the garage for about six years. I removed the v8 & automatic to put a six in it. I've had a 261 sitting in it for a while now. The engine has only 42,000 miles on it, but the # 6 piston stuck in the cylinder while I had it stored.I removed the piston and the cylinder will clean up with a little honing. Yesterday I bought another 261. It's a 58 model and has been remanufactured according to a decal on the block. I am going to install it in the car and fix the other one when I have time.I'm trying to decide which transmission to use. I have a '57 three speed , a similar trans with overdrive, and a later, fully syncronized three speed.I think the od would be nice but I've never owned a vehicle with overdrive , that worked, before so the installing and driving would be a new experience for me. The car has a 12 bolt Nova rear with 3.55 gears, if I remember correctly.My goal is to have the car on the road again in six weeks.

That will be a lot of work to do in 6 weeks. Keep us posted on your progress.

Tom
I have the Saganaw gearbox with overdrive in my Elcamino. I love it! Full syncro, and over 20 mpg. On a 1600 mile cruise through Idaho, over the rockies, up into Montana, over the Rockies again, and back to the begining of the cruise my average for the trip turned out to be nearly 24mpg. At first I was flabergasted because the #s worked out to 22.96, but on a subsequent trip I did a DOT speedo check and found my odo was running 5% under. That would have put the mileage up into the 24mpg range. I bought the tranny from Tom Lowe. THANKS TOM!! Tom nearly talked me into puting the OD unit on the back of a Saginaw 4 gear, but I wanted to keep my columm shift.
There was only 2 times during that cruise I mentioned that I had to kick it out of overdrive to climb through a mountain pass.

That sounds great. I too am fond of driving with the Borg ODs. With a 261 and 3.55 you can cruse 70-75 all day. I just got a 261 from a friend. I don't need it but I got it.

If you had the skills to mate the o/d and the fully synchronized tranny that would be awesome, but I never had that much trouble driving around without synchronized first. However I had 4.11's, so I left in second most of the time. The 3.55's may change that. 3-on-the-tree with o/d is/was GM's best tranny setup.

I have the schematics somewhere for the o/d wiring harness if you need them.

Perhaps Tom Lowe will drop in and answer the question about what the changeover involves. I know that one hole has to drilled into the back of the 4sp case for the reverse/OD lockout rod.

There are times when you can just step on the clutch and just haul her down in low without any clash or crash even with a non-synchro low. If memory serves (or swerves) I think its when the govenor kicks it into the freewhweeling mode, usually below 30 mph (if the governor is wired into the circuit). So while an all synchro is nice, it is not require for slipping back into low while still rolling..

Now, as an aside, an advantage of the crashbox is that it can be fitted with a 2.94, a 2.54(?), or a Corvette 2.20 low gearsets- just need a matching cluster, second gear and the main(?) gears (the one with the clutch spline on it). Its just an easy swapping of parts within the stock case, be it "55-'64 pass, vettes, pickups, and '62-'64 chevy twices (case length makes no diff). It may be easier to find an o/d to fit this tranny than the more rare Saginaw o/d

I personally rode in an early '40 sedan w/ 278 incher, mellings lopeing cam and full 'vette carb/exhaust setup. It was a good daily driver with a 2.20 low crash box (oh yeah and a 4.11 rear gear), with the 4.11 it would soar past 40 mph in low! The owner had installed this gearset into a 40 ish pickup (floor shift) tranny and was still using his stock 4.11 torque rear end- the later model tail shaft had to be used and machined to suit the torque tube settup both for length and matchup to the single splitable u-joint used on these torque rears. This was a really clever setup.

The O/D conversion to a saginaw 4 speed is not that bad. There are a few tricks. Basically you will need the 3 speed o/d(full syncro model) and a Saginaw 4 speed. Then mix them up. The 3 speed full syncro model is hard to find.

Greybeard,
Glad to hear the trans is working out so well for you. They will work great with stock or moderately hopped up 6's. Tom

Do searches here and on other sites. There is a lot on this topic. Example try "sag OD" here for a start. The Old Berb Club has info. Hot Rod Magazine did an article in April or May of 1970. Search on the H.A.M.B. The 3 &4 speed Saganaws involved used the same case. When removing the OD from the 3 speed you must also take the main shaft. Remove the 2nd/3rd slider. Put the 1st/2nd & 3rd/4th sliders in it's place. There is room. You must drill a hole in the rear of the case for the reverse kick out. Borg ODs don't like to run backwards! You can wire the governor to have OD in all forward gears at any speed. Panic pointed out that most of those ratios are fairly redundant. The main advantage of the 4 speed OD is the 4th over for the highway. Of all the '30s-60s cars and pickups that ran Borg ODs there are two basic models. The R-10 has 3 planetaries and the R-11 that has 4. The R-11 is said to be quite a bit stronger. The best combo I know of for strength is the Borg T-85 3 speed with R-11 OD used in some Studebakers and Ford pickups. The Saganaw 3 speed OD units are hard to find. The unique long shaft 12v solenoids for them are rare. Never throw away a Borg OD solenoid! They can be repaired.

I had time to work on my engine today. Turns out it's not a 58 model 261 like I thought. The number in the casting date I thought was a 8 is a 3.That means the engine block was cast in late 53, and it is a 54 235.I believe that 54 235s had the "captains bars" cast into the block , like all 261s.That's why I thought it was a 261 ,with the casting date being 1958.Oh well , it runs great and now I won't have to deal with the long to short water pump swap. I'm still going to install it in the 40 and drive it.

235's had bores of 3-9/16, and 261's stock bore was 3-3/4. I had a '54 with a 235 but never paid attention to serial or casting numbers, I never knew about captain bars 'til I got here,maybe thats why the strip inspectors always made me run in a sportsman class after I tried to claim 235, when I put my 261 in it.

I know the 261s had their year cast in the inside of the crankcase, In 1959 they started adding the full flow oil filter provision, so this was an easy id to id the long shaft water pump 235/261s "55 thru '62. I just dont trust the casting/serial number stuff.