I am doing up a mild 454, with a Magnum 280h Comp cam and 10.0:1 cr, and a Holley 750 CFM with vacuum secondaries, to replace the big block in my 55 Cameo. I have been contemplating going back from a modified TH400 to a manual transmission. I do have a super T-10, but I also have a truck 3 speed, with the advantage of it having an overdrive. I intend to use it for the street only, 3.90 gears, and won't be running really fat tires. Does anyone have any idea about how durable this 3 spd transmission would be for this application? I am 74, but my foot still slips sometime and I don't want something that is going to break.
I would not do it.... I kept the 3 speed in my 59 truck for about a week when I swapped in the 396 many years ago, it sure sounded like it didn't like the load on it, in second gear. And the overdrive can't handle a lot of torque, either. If you want to find out how strong it is, give it a try.
Thanks, I think I'll just go to the T-10. I am getting to old to want to do things twice. I have a Hone_O_Drive overdrive, that I have been using behind my TH400, and I can use that behind the T-10. It just means shortening the driveshaft a little.
Wow, I'm surprised. I have had this installed against a 350 HP 396 since 1971, and it is still in great condition. Did you repair it? If so, where did you find the parts? Bob
Jim has a lot of lead in his right shoe. My experience with tri 5 truck three speeds says that they don't handle a lot of horsepower but are relatively easy to work on. That was behind a little 327 with 12.5 pistons and an Engle cam with a Corvette 2x4 setup.
My hone o drive lived for a few years behind a couple different mild big blocks, then one day the ring gear split in half. I guess I got lucky.
I know that feeling, I used to only have two speeds, full speed and repair. I am a little more sane now. It is much less expensive. Thanks for the input. Bob
I guess finding parts for one would be like searching for a unicorn. I have always been kind to it while it was in overdrive, and confess that I have an emotional attachment to it. They must have used off the shelf parts from some big manufacturer such as Borg Warner. They were just a small machine shop in Santa Fe Springs, CA.
I remember when Hone O Drives were popular and if memory serves right they mostly went into what served as RVs at that time.
I just looked at your truck. I bought mine in 1969, and installed the 396 in 71. Did you bang in the firewall on the driver's side to clear the head? I used the old mounts which made that necessary. It is still ugly in that spot.
That's about the same time my Dad put in a 454/TH400 in his '57 PU. He made new mounts,never touched the fire wall, did have to move the steering box some to clear the Vette exhaust manifolds, doesn't turn as sharp the left though
Been a long time but we used to look for late 60's the fully synchronized 3sp with the "bump" out on the cluster side of the case. These usually had the 3.00 first gear and second was right for our old roundy car plus they held up well. As engines grew saltier and tires stickier we switched to the Ford top loader 3sp which was not a hard swap. The short tail Ford van trans were a very tough unit and compact enough for tight spaces. Pretty sure one could handle a 454 with reasonable tires.
If you don't want a hole in floor with a little work you can make the 4speed work off the 3 speed stock column shifter and use a Morris cable for reverse mounted under the dash like the overdrive handle was. Look how the 3 speed arms a situated and you can make some putting the arms in the same place for the 4 speed. If it were me I know I'd try it...
I am on my third set of headers, and in each case, I had to cut the the last two tubes on the drivers side and custom fit them tight into the block to clear the stock steering box.
I used the Hedman headers for 68-87 trucks, they fit pretty good, with the stock steering box, and the stock firewall. The engine is offset to the pass side a little bit. The 70s exhaust manifold will barely clear the steering gear with the engine centered using the original manual trans bellhousing, if you do a little grinding. I had that setup in my 57 one ton.
My headers are good for now, I have used the truck headers but the ones I have installed are the 1 3/4 Doug Thorly car headers, and they are still good.
I always wanted to put headers on it, then sometime around the late 70's, HR Mag had a dyno comparison with the same LS5 engine I had (but in a '70 Chevelle...assume the same manifolds, I don't really know) and up till about 4000rpm, the HP/TQ curves were the same as when they installed some 1.75? headers, there was a few HO and TQ increases and things began to really favor the headers after about 4200 rpms, but heck, I shifted at 5500, and didn't see much advantage pushing that brick wall down the street. PS...them manifolds are still on it
What manifolds were on it before?...Are you familiar with the Vette ones of the era?...Kinda like the ones Sanderson has been making in the past many years. Can liken them to shorty headers.
I used headers because it was not possible to use the LH manifold without moving the steering box, and at the time, I had never done a steering system. I bought the install kit for the 55 car from Nickey Chevrolet, and modified it to work for the truck. I had 4.57:1 gears and big tires and with the Muncie 4 spd I had in it at the time, it would launch quite nicely. My wife wanted an automatic, so I sold the M21, which I still regret.
The original manifolds were from a 350 HP 67 Chevelle. I never thought to look for the Vette manifolds, and you're right, they probably would have worked.
I have a floor shift for the TH400, and I was hoping I could modify a 3spd Hurst shifter and add a separate handle for the reverse. I haven't looked at it closely enough to see if I can make it work. I have the 3 spd shifter. The OD is another shifter mounted through the floor
GM actually did use the Ford 3.03 toploader 3 speed in big block sedans in the late 60s. They called it, the Dearborn transmission. The 3 speed Saginaw was not up to the task.
See, my Dad bought a wrecked '70 Vette, in early '71, the 283 he had in it was pretty tired, my uncle was a used car dealer and hooked him up I was the 10yo kid in the pit with my Dad, holding a light, etc... He put the engine in straight up, then needed to move the box, dang truck was scary with the 3.90's...so he found a Jimmy with 3:08's, as that was what the Vette had in it...went past that now with a 12 bolt rear....anyways,I'm rambling because it warms me up to know others did the same thing before kits were available, It was fun then, and is still fun now
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