K10 w/472 Cadillac?

[vdb11]

Hey all, I am brand new here, I posted in the Welcome area with some info about me and my experiences.

Anyways I recently purchased a 71 K10 (or C10 4x4 whichever is correct). It has a target master 350 with the t350 trans. Its going to be my new daily driver, and it is a low budget project (like sub 5k including truck cost = 2k). Most of my money goes to my 1992 K2500 (you can see my welcome post).

Anyways I planned to just keep the 350/350 combo, but I recently spotted a 69 472 cad with trans for a really good price. It has 70k miles on it, but other than that I know nothing about it, like what pan it has or what it was out of, as the owner has not gotten back to me. Of course my inner wrench turner got excited. So I have been thinking about it lately. Adding in the fact that its a 4x4 adds some complexity as I will need to get a different tailshaft for the t400 I would guess as well as a rear sump oil pan?

What are your thoughts? It is all in the brainstorming stage at this point. I see it has been done in these body styles before, although i would prefer to not have to modify the firewall. While I would love to put a 396 or 454 in, they are hard to find around here and much more $$

Convince me either way!

[jocko]

Welcome. And don't do it!
Ha, just kididng, but only kinda. You mentioned "new daily driver" and that right there is reason enough to not go to the trouble of stabbing in a 472. You will need much more than you list as possible considerations. What's the front to rear length of the 472? There is a reason chev did not manufacture 4x4s with 402s. Also note that a 350 is mounted about 2" aft in a K vice C model. So, there is a little wiggle room - most usually use this to scoot the engine fwd a bit to make room for an O/D trans.

That'd be my recommnedation - take the $ you were gonna spend on the 472 and research and do an o/d trans swap - especially since it's a daily driver.

To your quesiton - K10 is correct for the terminology, even thought it will still say Custom or C or Cheyenne, etc on the fender callout (depending on year). If it is a K on the SPID, then it is an original 4x4. As a 71 350 4x4 1/2 ton, your VIN should start with KE141...

Welcome again and, if you buy the caddy motor, I'd save it for a hot rod sometime, not for a K10. My 2 cents only, it's a very cool motor, but a pita to do the swap for minimal benefit in a K10.

[Longhorn 70]

Welcome! I'd say no also. In a C 10 or 20 cool. In a K??? Not really I'd that a 383 stroker may be a better choice. Lighter and better fit. Caddy engines are pretty wide. If you do really want to do this, go 500 El Dorado motor. In for a penny, in for a pound.

[truckster]

"Daily driver" is the key to me. Unless your daily drive is only a couple of miles, the 472 is going to get really expensive to run. And it's going to be a pain to get it into your 4X4.

[Ol Blue K20]

Originally Posted by truckster

"Daily driver" is the key to me. Unless your daily drive is only a couple of miles, the 472 is going to get really expensive to run. And it's going to be a pain to get it into your 4X4.

And on top of that^ custom made mounts & brackets makes parts availability worse. You cant just go to the store or junk yard and pick up your parts.

[mrolds88]

Actually those Caddy engines get pretty decent mileage. You will have to get an Eldorado oil pan as it is a rear sump. Also get the oil pump pick up tube. Also since the Caddy has a front distributor, that gives a little wiggle room. Do your homework first!!!

[vdb11]

Thank you for the thoughts guys! keep them coming! I will definitely do some more homework. I would rather do a 396 or 454 but like I said they are hard to come by.

[68gmsee]

My brother had a late 60's early 70's Cadillac and he used to get around 10-12 mpg on the highway. Most trucks and big cars didn't get much better than that but gas was around 50 cents or less a gallon. Another thing to consider is that in those days an engine with 60K, 70K was closing in on an overhaul. They weren't like todays engines that go over 200K and still run strong.

[lousblown55chevy]

Keep looking for the 454 , try finding a surburban on Craigs List , pull the engine and acc. and scrap the rest. They are out there most of the big block guys are going with aftermarket blocks for more cubes , making the factory stuff cheaper

[Andriod8]

Great HotRod engine. Put it for the Power!

[mrein3]

The biggest hurdle I see with a BOP engine is the transmission. I've seen many "universal" 2wd th350s but never a 4wd one.

A guy could rebuild a BOP or universal th350 with the K output shaft and leave the tail off but I'm pretty sure there aren't any factory transmissions that will do what you're thinking without mods.
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[HeloCrewChief]

472's are awesome engines. Absolute torque monsters with little to no modification required. They are very strong engines as well. As others have stated; may not be well suited for a K series though.

[vdb11]

mrein, thats what I was wondering about myself. The engine Im looking at comes with the trans, which I am assuming is a th400, but with the wrong tailshaft. I am wondering if its even possible to change tailshafts so that it has the right spline count and bolts up to the transfer case?

I thought I saw somewhere that they made an adapter to run a BOP engine with a chevy trans. That could be an option but would that move everything around?

[Longhorn 70]

I have a BB Olds in my 70. It fits nicely. I don't like the extra weight in the front end. That extra 150 lbs up there made a difference on a C series. with a K series it would raise center of gravity as well as make the front end heavier which would make it climb less nimbly.

The Olds also breaks more drive train parts than the small block did. The added stresses in off road driving would multiply that.

It would seem the Caddy motor would do the same things. I am not an engineer though.

[ole dollor]

welcome to the forum from Texas, just have fun with it.

[mrein3]

Originally Posted by vdb11

mrein, thats what I was wondering about myself. The engine Im looking at comes with the trans, which I am assuming is a th400, but with the wrong tailshaft. I am wondering if its even possible to change tailshafts so that it has the right spline count and bolts up to the transfer case?

I thought I saw somewhere that they made an adapter to run a BOP engine with a chevy trans. That could be an option but would that move everything around?

All 67-72s that came from the factory with a NP205 transfer case have the same length of transmission/adapter/transfer case. A 1971 with a th350 probably is stock and probably has a th350 if auto because the general didn't put th400s in 67-72s.

There is a piece between the transmission and the transfer case on all trucks of this vintage. That piece is called the adapter. In shorter transmissions like the 3 speed manual the adapter is longer. In longer transmissions like the th350 the adapter is shorter. The general in 1971 was modular before GM knew what modular meant.

Now even though the general didn't make a th400 4x4 in 1971 that doesn't mean you can't do it. I "stored" a 4x4 71 or 72 for a guy for a while. When looking it over I noticed he had a th400 in there with a NP205 behind it. I'm guessing GM continued making that combo (th400/adapter/NP205) in later model trucks the same length as 67-72 4x4s to make building trucks easier.

If you or other readers didn't catch that let me give an example. I had a three-on-the-tree/NP205 in my truck when I bought it. 3OTT transmissions are great theft deterrants because 20nothing gang bangers couldn't drive one on a bet but they also like to jam at bad times. Because they like to jam I swapped to a th350/NP205. When I did that I had to do NO mods to the rest of the drive line. I dropped out the 3 speed/adapter/transfercase and lifted in a th350/adapter/transfercase. The drive shafts bolted on with no mods.

Now the reason I said I swapped out the transfer case with the adapter and tranny is because for a reason I don't know, GM made different input shafts on the same transfer case depending on what transmission was in front of it.

If you have a manual transmission, the input shaft has 10 splines.
If you have a th350, the input has 28 splines.
In a th400, though I've never broke one apart, I've read the input has 32 splines.

This is important because there is a part called a "drive sleeve" that couples the input of the transfer to the output of the transmission. This drive sleeve rides around inside the adaper. The spline count on the drive sleeve has to match the spline count on the transfer case.

Sooo....
REAL LONG story short. If you want to put in a 472 with a th400 in a 1971 4x4, you need to find a stock th400/adapter/NP205 from a later model truck. Then take that 4x4 - K case - th400 and a BOP bolt pattern th400 (the one you get with the 472) to a reputible tranny builder and tell him you want a rebuilt th400 that that will bolt up to a Caddy 472 that you are going to bolt to a NP205 so you need the 4x4 output shaft put in the tranny.

[vdb11]

mrein, thank you for the great post and great info!

I am much more familiar with the later model manual transmissions and tcases from doing the solid axle swap on my 92, but I am pretty unfamiliar with the autos in these years.

I guess finding the th400 and np205 could be a bit of trick, and finding a reputable trans shop may be even harder around here, as I am still in search of a good place to do my nv4500.

Thank you again for the help! This gives me alot more to think about.

longhorn 70, you are absolutely right. I saw somewhere someone said if you ever plan to lock the hubs in, you should be prepared to break things. The ultimate I guess would be a D60 front and 14B in the back, but even with a big block I would still be easy on the truck. Especially in 4x4. I don't use 4x4 for much except in bad snow or around the farm.

[vdb11]

Hey all I thought I would revamp this thread with an update!

I have been giving this alot of thought lately and I had somewhat changed my mind to using a tbi 454 from a 90s truck, possibly with the 4l80e or converting it to carb. But I now have a new plan.

I think I am going to swap a 6.2l diesel in it. I decided I want to get better mileage and for what I use the truck for, its going to be a DD. I won't tow with it, or need neck snapping power. If I want more power or heavy use, I will just use my 92.

My plan is the 6.2 with maybe a 700r4 so I can get overdrive. From what I have read so far, this shouldn't be that hard of a swap. Another reason for this plan is that this is my budget truck, and I already have a military 6.2 that I pulled two years ago at a junkyard that I can rebuild and throw in it. I think I can do this swap pretty cheap.

I know my way around a 6.2/6.5 WAY better than I do a carbed gas motor (or any gas motor). My first truck was my 92 and I have done extensive engine work to it. My goal is 19-20 mpg in town. What do you guys think? When I actually start the swap I may start another thread. It will be down the road though.

[vdb11]

I thought I would show you guys what I am working with. I finally got it on the road and inspected about a week ago!

I hope they loaded ok...

[yuccales]

That's a good looking truck!

[vdb11]

Thanks!

[68gmsee]

Now you're talking. A diesel, especially if you're familiar with them, would be a good swap. I've kicked around that idea in the past but diesels and I are not good friends.

Right now I'm rebuilding my tractor's 3 cylinder perkins diesel and little sucker is eating my lunch - but making slow progress.

[vdb11]

What tractor is it? I have never worked with a Perkins before.

The only reason I know much more about them is because its what I started with. I know the 6.2/6.5 platform pretty well so I think it would be an easy swap for me. I know how to diagnose and work on them much better than a gas.

[low&slow]

Don't know anything about diesal's, but I do know a little something about that caddy idea you had. You can use a chevy transmission if you buy a BOP/Chevy addapter plate. They work great. I have an addapter on my caddy in my 69 chevy. Also, you will need a rear sump oil pan and oil pick-up, late 70's to early 80's 4x4 mounts because it will need raised up to fit, and that's all you need. That's all I used to put a 500 caddy into my truck and did not have to modify anything to make it fit either.

Another thing is the caddy engines have Four 0 points to time it. If you do it like I did and hook up a pressure gauge to the distributor and make it so the gauge reads 35-40 pounds of pressure, then you can get right around 15 mpgs with a 650 cfm carb. That was my set-up before I got a lead foot.

Also, they aren't really that heavy. They're actually lighter than a 454.

[vdb11]

Thats interesting! How much get up and go did it have with the 650 on it?

Did you have to do any driveline modifications? Is yours a 4x4? I don't think i would really want the expense of custom length front and rear driveshafts....

Now I wish I had two of these trucks....