The Stovebolt Site Forums The Shop Area Driveline Transmission 1961 K10

As mentioned in another thread, I am restoring a 1961 Knee knocker. Someone had previously dropped in a 350, which was blown, with a TH350 transmission. My original plan was to get a crate 350 and a NV3500 transmission. I ran into a guy that has a marine 350 from a boat with less than 200 hrs on it that he would rebuild, and he recommended I stay with the TH. I am planning to use the truck as a daily diver. First I don’t know anything about boat engines other than they run at 4000 RPM all day and second would the TH350 3 speed be a better daily driver choice than the 5 speed manual NV3500?

The only difference between trannies is whether you enjoy rowing. Since you're putting in a boat engine, the manual tranny might be appropriate.

Really, I know nothing about the two transmissions, I just couldn't resist using the boat thing.

Was the marine engine Fresh Water Cooled? If not and it was used in salt water the water jacket might be a mess. Also, the marine engine might be a 4-bolt main.

Can your engine guy built it cheaper than buying one from Jegs or Summit with a warranty?

The NV3500 will give you Overdrive, the TH350 will not, if fuel economy matters.

Mike B

That is what I was thinking

I have 3 on the tree in a 48 Nash and a 67 bug, so I guess I like rowing. My first choice normally is a manual. The engine guy was really high on the TH350 for a K10. For a C10 he would have gone a different route.

The only better choice than a TH 350 for your truck would be a TH400. Manual transmission vehicles also need to be equipped with a hand crank for starting and an acetylene generator for lantern style headlights. All those things are the same degree of obsolete. With the right rear end ratio, having an OD gear in the transmission becomes a moot point. Make sure the boat engine is a clockwise rotation type- - - -the CCW engines have a lot of special modifications to the camshaft drive, and a rear main bearing seal that is unique to that type of engine. Wrist pin offset in the pistons might also be different.
Jerry

Gary, just a shot in the dark question. What transfer case is currently in the truck??? Your pictures of the rear axle in your other thread don't show the rest of the driveline. Are you still running the original divorced transfer case or are you using a TH350 with tail shaft mounted transfer case???

The NV3500 doesn't have a "granny" 1st gear if that is important to you.

I have to disagree with that, Jerry. A manual tranny truck can be push started. Try that with an automatic. Years ago, I came across a guy stuck in the ditch with another truck hooked to him trying to pull him out. The puller truck was an auto tranny and he couldn't get it to budge because his torque converter had stalled out. I hooked up to him with my manual tranny K10 Chevy and walked him right out.

It had a tail mounted on the TH350. I also have one tail mounted to a SM420 that was sitting in the bed of the truck when I got it.

The other thing I like about a manual is that you don’t have to lock the door. Car thieves don’t know how to drive a stick.

Let alone a three on the tree!

Thanks for the reply on the transfer case question Gary. Me personally, I would opt for the stick but if you intend to use it as a daily driver and need to be able to keep up with traffic, a TH400 may be the ticket. I think (someone will correct me if I'm wrong) that a change from TH350 to TH400 though would also mean a change in your transfer case - ka-ching!!!

More likely, the adapter housing between the transmission and the transfer case might be different, but the T/C might be the same- - - -possibly for both the stick shift and the automatic(s).
Jerry

Old automatics could. The Powerglide in my '59 Impala and the HydraMatic in my '57 GMC both had rear pumps which provided enough hydraulic pressure to operate the transmission to get the engine turned over from a push.

The Nash is a blast to drive. It has a WB overdrive 3 on the tree. It will cruse at 65 easy but get 10 mpg. You think it would do better with a 6 cylinder OVH cam.

Thanks for the comment, I will look at the TH400. I see that the 4L80E has an overdrive. A rebuilt one is about $3,300. I am sure my TH350 won't do as a core so the core charge will likely apply.

A 4L80 also needs a computer, and several electronic inputs to work properly. It's a solution desperately searching for a problem to solve.
Jerry

What transfer case are you using?

Also the trans should be a "K" case.

I hope to use the one of the two I have. I will have to do some research to see what the are.

I don't recommend using a boat motor. I don't recommend having a motor rebuilt, especially by a guy you "ran into". Buy a good runner with good compression and no oil leaks or a crate motor.

A 205 xfer is the best.

A TH400 and a TH350 have different output shafts. You can use the same transfer case, but will have to change the input on it to match the output shaft on the transmission.

And because reasons, the input is one of the first things to go in during assembly so it will require a full teardown.

Facebook market place list a 2004 Z71 that a a rebuilt engine and transmission. “3 weeks after putting back togather” he wrecked it and bent the frame. Say he has the rebuild paper work. Transmission is a 4L60. Seems like I remember 4L60 had clutch problems or something like that. So given he will take $2300 if I haul the truck away
1. Would the 4L60 be a good way to go?
2. Can I get a custom wiring harness and reprogram the old or a new ECM to the reduced functions on my 61?

Side note the engine rebuild included a stage 3 cam. Not sure the loss of low end torque for high end performance is really desirable for a K truck, other than how it sound sitting at a red light.

The short answer is that you can get an aftermarket ECU for the 4L60e if you want one, but the decent ones are close to a grand. The stock truck used the same ECU for both engine and transmission control so trying to use it with your older engine would be an exercise in frustration.

The newer transfer case won't do you any good because it is a driver drop and your truck (assuming stock) is a passenger drop.

Depending on what engine is in the donor truck, you might be able to pay for the standalone controller by selling the engine/TC out of it. If so, that could be a decent choice.

Better yet, just take the whole engine/trans combo out and LS swap your truck. Then you don't need the standalone transmission controller.

Another thing to consider in this process is that if you are switching to an automatic transmission, you will need a transmission fluid cooler to go with it. How large of one will depend on what trans you get and how you set up your torque converter.

Thanks, I checked and the transfer case I have on the TH350 is a 203. Since it was installed in the 61, I assume I have the crossmember needed to mount 4l60/203 in the truck. I saw a comment on another board that mounting a 203 to a 4l60 was a dumb idea. I am guessing that is because the transfer case is mechanical controlled and not electronic. I will still have to lock my hubs so electronic selection really does not gain much. is there another reason not to reuse the 203?

Old thread new comment. Had some issues with my 67 vw bug that took me away from my truck project but I am back on it now. The questions about which transfer case sent me digging. I have an NP203 and had planned to use that. After looking at what would be required I think plan B is in order. I think my plan will be to purchase an early 2000ish suburban or tahoe as a doner for engine and transmission. Those seem to hold their value less than a Z71 PU. For a transfer kit I will buy a NP241C. I found a kit to switch the mechanical speed sensor with an electronic VSS. From my research that should all mate up. Is there something I am missing? Is there a better model year to target for the doner?

The NP241C will bolt directly to a 4L60e with no fuss. They were available for a couple years with a VSS from the factory, so you could get lucky.

A 2000-2002 Suburban will have a mechanical fan and cable throttle. An 03-06 will have an electronic throttle and (usually) an electric fan.

A 2000 will have an AIR pump and EGR. You can easily remove those in the tune, but you will have to get blockoff plates for them. The price difference for a slightly newer one that you don't have to mess with is negligible.

There are some differences in the wiring, the coils, and a couple other small changes between the 00-02 and 03-06, so you will want to keep track of what your donor was.

Thanks great info. From what I read I am unsure I could find a right side dump transfer from an 03-06. The VSS kit was only $140 and looked to be an easy (nothing ever as easy as it looks) fit.

You can use any NP241C, not just an 03-06 one.

The 700R4 has the same mounting flange and output shaft as the 4L60e, so anything that had one of those will bolt up and work just fine.

Any of the 2000+ 241Cs will be driver drop.