86' M1008 - Contemplating Chevy 350 engine swap

[Commander5993]

Hey all,
We have a 1986 M1008, which (short version) blew a head gasket, found out later that both heads are "riddled with cracks".
This is our daily driver, we need it to be dependable. So we are looking to install a new engine.

I know of the "optimizer" and other upgraded 6.2/6.5's etc, which run about $5-8k. We couldn't go that route right now even if we wanted to.

I have see some of the 'purists' etc arguing why we should not change the 6.2/6.5 for something else. I don't want to start any more arguments.

This is currently just at the "thinking" stage. Just looking at options.
What I am needing to know is *if* we were to change to something like a chevy 350 engine, what else would have to be changed? I've found some info about it, seen that some people have done it, but not much details.

From what I understand:
*The TH400 transmission will bolt up... but the torque converter may have to be changed?

**I know the wiring has to be changed some, as the CUCV has a 24v system... well partially at least. Actually as far as I know only the starter is 24v on the CUCV isn't it?? Wouldn't it be simple to pull power from the 12v rail instead of from the original 24v location??
*The alternator(s) may be a different story. There seems to be conflicting info about if the 350 is a single wire or 3 wire, and what has to be connected to where.
*I'm fairly decent at working on dc wiring (a lot better than most... especially with some of the "work" I've had to fix...) but I've never had to change an engine from one voltage to another. So I just have to understand what would need to be done.

***The power steering pump and hydrobooster for the brakes seems to be another issue. Although some people have stated that there is a bracket that can be purchased for the 350, or a bracket can be made.

****Not sure how much modifications to the exhaust would be required.

I'm sure there is stuff like radiator hoses etc that would have to be customized. That can be done.

Is there any other major items that would have to be changed??
Any other needful points etc?

As always,All Help and Input is Much Appreciated!
~Thanks
Warren

 

[Commander5993]

???

 

[richingalveston]

there are a lot of 350 swap threads, search and you can find all the info needed.

you will need to change or alter the existing wiring harness. not a big deal, look at Roscommon method and follow that to make existing wiring harness 12 volt.

you may need all new mounting brackets for the alt and ps pump, your alt and ps pump will probably work

might be best to find wrecked square body truck and get all the parts you can.

most 350 blazers had 700r4 tranny. the th400 will work but your gas mileage may not be that good at highway speeds.

rich

 

[Commander5993]

there are a lot of 350 swap threads, search and you can find all the info needed.

Ok, I'll search some more. I tried searching using the SS seach, but kept getting "Sorry - no matches. Please try some different terms." even when just using the term "350".
I ran a few searches on google, and other than people just saying they had done it or asking a specific question, I had only found 1 thread here and another short one on a different site.

you will need to change or alter the existing wiring harness. not a big deal, look at Roscommon method and follow that to make existing wiring harness 12 volt.

Yeah, I knew the wiring harness could be "made" to work. Just didn't know the details. I had also seen some people saying that it was "better" to just replace the harness with a custom one or something. Thanks for the info, will look up the method you mentioned.

you may need all new mounting brackets for the alt and ps pump, your alt and ps pump will probably work.
might be best to find wrecked square body truck and get all the parts you can.

Ok, good to know.

most 350 blazers had 700r4 tranny. the th400 will work but your gas mileage may not be that good at highway speeds.rich

Hummm, ok. If I was to change it to a 700r4, will that work with the current diff and 4 wheel drive?
I'll look into it.

Thanks for the Info Rich

 

[Commander5993]

going to try to use google site search to search SS...
the SS search is very aggravating... it will only let me run one search per minute, 50 seconds technically. Further, I keep getting the "Sorry - no matches. Please try some different terms." even when I know the term exists in the sub-forum (like CUCV or CUCV mod). Plus I can't try a different term for almost another minute, I can run 5-6 searches while I'm waiting to run one....

anyway... rant over

 

[JUNKYARDJOHN]

JEGS has a 350 with a roller cam, vortec heads & a 4 bolt main. Brand new with a 36000 mile warranty for $ 2050. I can't build one for that. I bought two, one for my 1009 & one for my towtruck. Both are still in the process. You wont be sorry. John

 

[Commander5993]

JEGS has a 350 with a roller cam, vortec heads & a 4 bolt main. Brand new with a 36000 mile warranty for $ 2050. I can't build one for that. I bought two, one for my 1009 & one for my towtruck. Both are still in the process. You wont be sorry. John

Thanks John for the info!
Thats something I will definitely look into.

.... Somerset huh.... I grew up near London
been to Somerset many times when I was younger.

...like your signature too

 

[Commander5993]

JEGS has a 350 with a roller cam, vortec heads & a 4 bolt main. Brand new with a 36000 mile warranty for $ 2050. I can't build one for that. I bought two, one for my 1009 & one for my towtruck. Both are still in the process. You wont be sorry. John

Is this the engine you were referring to? https://goo.gl/EjQRgp
I didn't see it at first because it keep listing it as 1996+, but in the specs it shows 1986+

Have you already installed yours?
The "painless wiring" you referred to, did you get that from Jegs also?
~Thanks Again

 

[quickfarms]

Is this the engine you were referring to? https://goo.gl/EjQRgp
I didn't see it at first because it keep listing it as 1996+, but in the specs it shows 1986+

Have you already installed yours?
The "painless wiring" you referred to, did you get that from Jegs also?
~Thanks Again

Any idea on the hp spec?

I am looking for a small block to put into my G506

 

[Commander5993]

Any idea on the hp spec?

I am looking for a small block to put into my G506

I was wondering the same thing, Jegs doesn't list it, so I googled it by the engine number, but no one else seems to list it either. I did find a forum where some guys were talking about this same engine comparing it to another, and from what they said it is 260hp, but I don't know if that is correct or not.

I did email Jegs tech support and asked them, although I doubt I get a response until at least monday, but when I do I'll post it here.

 

[patracy]

going to try to use google site search to search SS...
the SS search is very aggravating... it will only let me run one search per minute, 50 seconds technically. Further, I keep getting the "Sorry - no matches. Please try some different terms." even when I know the term exists in the sub-forum (like CUCV or CUCV mod). Plus I can't try a different term for almost another minute, I can run 5-6 searches while I'm waiting to run one....

anyway... rant over

Use the google search bar on the main screen. The internal vBulletin based search you're trying to use is time limited due to the hit on the database it causes. The google search works independently and doesn't have the time limit. Also it doesn't have the 4 character search requirement.

 

[patracy]

1390 hits on "CUCV 350 swap" with the google search.

https://cse.google.com/cse?cx=partn...2630#gsc.tab=0&gsc.q=CUCV 350 swap&gsc.page=1

 

[Commander5993]

Use the google search bar on the main screen. The internal vBulletin based search you're trying to use is time limited due to the hit on the database it causes. The google search works independently and doesn't have the time limit. Also it doesn't have the 4 character search requirement.

I'll keep that in mind Patracy, Thanks for the info

 

[rustystud]

I converted mine several years ago . I installed a "383 Hi-Torque" in it. I kept the TH400 and the NP205 transfer case. I replaced the factory wiring with a used harness from the local junk yard. I kept the large radiator and just had to use an adapter for the upper hose. I rerouted the transmission cooling lines to the radiator engine oil cooling ports, and the used the transmission ports for cooling my power steering. Truck has worked great ever since. I also changed out the dash and installed a tilting steering column.
Now I get much better fuel mileage and more power to !

 

[Commander5993]

I converted mine several years ago . I installed a "383 Hi-Torque" in it. I kept the TH400 and the NP205 transfer case. I replaced the factory wiring with a used harness from the local junk yard. I kept the large radiator and just had to use an adapter for the upper hose. I rerouted the transmission cooling lines to the radiator engine oil cooling ports, and the used the transmission ports for cooling my power steering. Truck has worked great ever since. I also changed out the dash and installed a tilting steering column.
Now I get much better fuel mileage and more power to !

better fuel milage with the 383??
We were getting about 22-25mpg with the 6.2, not pulling a trailer or anything, but even with the bed loaded it didn't change much.

"...installed a tilting steering column..." .
do you have to change the dash in order to install a tilt steering? I'm guessing you changed the dash for other reasons?

 

[Commander5993]

Any idea on the hp spec?
I am looking for a small block to put into my G506

I was wondering the same thing, Jegs doesn't list it, so I googled it by the engine number, but no one else seems to list it either. I did find a forum where some guys were talking about this same engine comparing it to another, and from what they said it is 260hp, but I don't know if that is correct or not.
I did email Jegs tech support and asked them, although I doubt I get a response until at least monday, but when I do I'll post it here.

Got a reply from JEGS:

Thank you for giving Jegs the opportunity to assist you with your technical question.
These engines are rated at the factory rating of 250. Let us know and we will get one coming.
If you have any further questions, please feel free to contact us.
We are dedicated to providing our customers with the very best in selection, value, same day shipping and lifetime support, thank you for choosing JEGS!
Jon Shook
Technical Sales Representative
800-345-4545
ext #639
Jon.Shook@jegs.com

Jon Shook
Jeg's Customer Service
1-800-345-4545

 

[Commander5993]

Ok.... well... i've been trying to figure out what all parts I would need to take that 350 long block, and get it to a fully running engine.
Since I don't have a 350 "donor"... that means that all the parts you could normally "swap" from your 'old engine' to your new long block, I don't have any of those.
So I have to start from scratch.

Yeah, I know many people are able to go to a junkyard a get a few parts or a whole donor engine to use. However we live "out in the sticks" here, only a couple small towns within 30 miles or so, and only really one scrap yard, and they don't really keep any vehicles. Any "real" junk yards would be 75 to 100 miles away near the "big"er cities.
So with that in mind, I might just buy the parts new and forget it. But that means it's more than double the cost of the long block itself. Although I "upgraded" a few parts a little bit.

I have compiled a list on Jegs, (which I'm going to try to attach in the pdf file below, crossing fingers that it shows up right) starting with the long block GM engine that I believe is the one JUNKYARDJOHN was referring to. Although I tried to find a fully dressed engine at a better price, but they all seemed to cost more, and still were not "fully dressed" in my book, as most still needed everything upfront.

Anyway, I added all the parts that I have come up with so far. I am certainly forgetting some things, I'm sure. I also am not 100% certain on a few of the parts. Such as the mechanical fuel pump I have listed, I think I read somewhere that the vortec engine doesn't have a place to mount a mechanical fuel pump and that it requires an electric fuel pump instead. They really need to have more detail listed about these engines, or have a link to a full manual about the engine or something...

I also sent Jegs an email to their technical support, asking about the water pump, alternator bracket, motor mounts (as Jegs only seems to list just the rubber part of the mount instead of a complete mount), and a few other things. I'm also still not certain if the flexplate and flywheel are correct when concerning bolting up to the TH400 transmission. I've been reading a bunch of the posts that Patracy linked in his Google search, many are still kind of vague and fuzzy on the details. Also many of the photos that were linked to sites like "photobucket" no longer exist either. Going to do some more searching.

Anyway, here is the pdf file of my "parts list". Hope it posts correctly.
If anyone would like to look it over, all comments and suggestions on this list - or - other options, would be Much Appreciated!
~Thanks

------------------------
UPDATE:
I just heard back from Jegs (which I wasn't expecting to hear back this quick), so with the information they gave me, I updated my parts list. So I'm posting the updated list below:

View attachment engine list update.pdf

 

[rustystud]

better fuel milage with the 383??
We were getting about 22-25mpg with the 6.2, not pulling a trailer or anything, but even with the bed loaded it didn't change much.

"...installed a tilting steering column..." .
do you have to change the dash in order to install a tilt steering? I'm guessing you changed the dash for other reasons?

The "383 Hi-Torque" has tremendous pulling power so you don't need to get your foot into the throttle so much for one. At highway speeds I can get up to 27mpg empty and 20 to 24mpg (depending on the terrain) pulling my trailer. It's all in the "cam" and that extra length of connecting rod for leverage. I replaced the dash because I didn't need all the "2nd alt" stuff and other warnings that come with the standard CUCV. At the time I just wanted a regular Chevy truck, so I eliminated all the military stuff. Like the rifle holders behind the seat, and the front bumper and pull hooks. I kept them though. Maybe later I will but them back in. I also added some "chrome" to the truck ! Flashy !!! My wife actually said I should turn it back into the military truck and paint it "Camo" ! Surprised the crap out of me when she said that ! She usually doesn't say nice things about my deuce ! She usually refers to it as "the other woman" ! I'm pretty sure that is "not" a compliment ! So when she said that about the CUCV I was taken totally by surprise. She said it would be "cute" ! . Not how I would describe my truck, but well there you are.

 

[Commander5993]

The "383 Hi-Torque" has tremendous pulling power so you don't need to get your foot into the throttle so much for one. At highway speeds I can get up to 27mpg empty and 20 to 24mpg (depending on the terrain) pulling my trailer. It's all in the "cam" and that extra length of connecting rod for leverage. I replaced the dash because I didn't need all the "2nd alt" stuff and other warnings that come with the standard CUCV. At the time I just wanted a regular Chevy truck, so I eliminated all the military stuff. Like the rifle holders behind the seat, and the front bumper and pull hooks. I kept them though. Maybe later I will but them back in. I also added some "chrome" to the truck ! Flashy !!! My wife actually said I should turn it back into the military truck and paint it "Camo" ! Surprised the crap out of me when she said that ! She usually doesn't say nice things about my deuce ! She usually refers to it as "the other woman" ! I'm pretty sure that is "not" a compliment ! So when she said that about the CUCV I was taken totally by surprise. She said it would be "cute" ! . Not how I would describe my truck, but well there you are.

LoL

I hadn't never heard of a 383 Hi-Torque until you mentioned it. Sounds like the perfect engine for a CUCV.
Where did you get it? Used? New? What did it cost you?

 

[The FLU farm]

Ok.... well... i've been trying to figure out what all parts I would need to take that 350 long block, and get it to a fully running engine.
Since I don't have a 350 "donor"... that means that all the parts you could normally "swap" from your 'old engine' to your new long block, I don't have any of those.
So I have to start from scratch.

Have you considered buying a donor car? It's often less costly and definitely more convenient than chasing down all the individual parts.
Then you can sell the leftovers, sometimes even making a profit.