cucv m1008 6.2 to 454 big block swap questions.

[CUCVLOVER]

Hello everyone,

I am starting to get tired of having issues with my 6.2 n/a diesel in my 1986 m1008 and am thinking about swapping in a 454 big block gasser. I know where a 1989 motorhome with a 454 and a th400 transmission is, that im thinking about getting the engine and transmission out of and putting into my truck. I know that with the 4.56 gears and no overdrive it will pull like a train and drink gas faster than a topfuel dragster but im ok with that. I know this truck will loose some of its authenticivsm but the truck already has a flatbed, kc lights, different wheel, stereo and stuff so its customized to me and I don't plan to ever sell it (how can I sell my first truck).

I have a few questions im hoping the great minds of this forum can answer.
1: If I use the transmission that is already on the 454 will my transfer case bolt up? Will I need a different adapter block or what?
2: What wiring do I need to keep from the 6.2? I have read that the pink wire from the injection pump can go the ignition and if I wire the batts in parelel instead of series to have 12volts I can use the same starter circuit, is this true?
3: I know I will need a different throttle cable. It should be one for a 1984 k30 with a 454 correct?
4: On the motor mounts what will I need to do?
5: If I use the powersteering pump from the 6.2 I wont need a new brake booster with a vacume port correct?
6: I want to keep the huge radiator that the diesel uses so what will I need to do about the oil cooler and transmission cooler lines?


thank you all in advance for your help and wisdom.

 

[CUCVLOVER]

here are some pics of my truck, having been a member here for a while I know pics are greatly appreciated

Thanks again.

 

[CUCVLOVER]

Anyone?? Please

 

[marchplumber]

Sorry big guy, I have zero experience with the afore mentioned swap....... So I can give any useful information...................I will offer "moral support" though, there are quite a few member here who have done similar swaps, I don't know about the 454. Best of wishes, and hope someone with more knowledge chimes in for ya!

 

[NDT]

The 454 will bolt to your existing th400 but you need to use a torque converter designed for a gas engine. Yes the pink wire can power your ignition coil on the 454. Use the power steering pump from the diesel on the 454 and keep the hydroboost brake system.

 

[CUCVLOVER]

Thanks for the info guys.
I was starting to think y'all didn't like me anymore haha.

I'm seriously thinking about doing the swap if it looks like the 6.2 won't be ga rally ready.

 

[Recovry4x4]

Will the 454 be road ready? Lots of little details to work with. Firstly, motor mounts will swap over. It would be ten times easier to keep the trans in the truck then use the one out of the coach. Speaking of the coach, does it have hydroboost? If so it simplifies you PS pump install. Don't forget clearing out fuel tanks, possibly running new lines and oh yes, exhaust. It's not a particulary difficult swaps but there are a few changes that need to be made along the way. Reconfigure your battery cables so that everything is 12V and you should be OK there. I see the coach is an 89. Is that a G chassis, P chassis or workman chassis? Migbt be fuel injected as well. It's not a weekend swap for certain.

 

[CUCVLOVER]

The 454 runs, just might need a new carb it pulls it's self just the body is all the poo.
Dont know for certain If the coach has hydro boost or not.
My Uncle ended up with the thing and is going to part it out since most of the body is rotted but the drivetrain and genset it had was good.
On the fuel lines I figured blow out the steel sections and replace the rubber, on the tank drain it out and wash out with paint thinner. My truck already has a true duel exhaust that I had put in it and the exhaust shop is about 15 minutes from my house so I hope that wont be much issue.

So the 6.2 diesel mounts will bolt up to the big block?
Thanks again

 

[rustystud]

The 454 will bolt to your existing th400 but you need to use a torque converter designed for a gas engine. Yes the pink wire can power your ignition coil on the 454. Use the power steering pump from the diesel on the 454 and keep the hydroboost brake system.

Actually the torque converter will be fine, and really is the one you would want anyway. There is nothing you need to change from the transmission back except the exhaust system. The power steering pump should bolt over also. Just get the correct brackets for the 454 engine. The radiator is also fine and the cooler lines can be utilized by your transmission and power steering pump. That is what I did. I put the transmission lines into the engine cooler side and used the "old" transmission cooler for my power steering pump. It works great ! Has now for almost 20 years. As far as the electrical system goes, I gutted mine and went with a take-out harness from another Chevy truck. Of course mine had had an electrical fire !

 

[11Echo]

Make sure to use this fuel pump.

https://www.summitracing.com/parts/CRT-M4530/

 

[rustystud]

Make sure to use this fuel pump.

https://www.summitracing.com/parts/CRT-M4530/

That is a really good fuel pump and a great price.

 

[11Echo]

That is a really good fuel pump and a great price.

The most important thing is, it fits. The "large can" fuel pumps have a clearance problem.

 

[CUCVLOVER]

Thanks for the info guys.

I will have to convert to electronic fuel pump I'm 99% sure. He said something about it had a in tank fuel pump. I looked at the engine a little bit yesterday and I seen a far amount I'd change. It's headers, carburetor, dipstick tube for a pick up, and a lot of junk ripped off and thrown away haha. Apparently it had the emissions package on it.

 

[rustystud]

Thanks for the info guys.

I will have to convert to electronic fuel pump I'm 99% sure. He said something about it had a in tank fuel pump. I looked at the engine a little bit yesterday and I seen a far amount I'd change. It's headers, carburetor, dipstick tube for a pick up, and a lot of junk ripped off and thrown away haha. Apparently it had the emissions package on it.

The CUCV's do not have in tank fuel pumps. A regular pump will work just fine.

 

[CUCVLOVER]

The CUCV's do not have in tank fuel pumps. A regular pump will work just fine.

I meant on the coach it has a electronic fuel pump.
I don't know fr sure if it's an intank or a inline pump. I haven't had much chance to look at it.

 

[Bob H]

the 89 454 would be throttle body injection, which uses the an in tank pump with a return system.
swapping to a carburetor would solve that, I don't know if the 89 would have the place or cam lobe for a mechanical fuel pump, so an inline electric there.

The TH400 i the CUCV has a very low stall speed torque convertor, I would put the one from the gasser in the cucv trans, there is also the shift governor in the trans, it has pretty a low shift point, this can be adjusted after the swap if necessary.

 

[CUCVLOVER]

How do I adjust the shift governor?
Thanks

 

[rustystud]

How do I adjust the shift governor?
Thanks

Honestly unless your going to be revving up this 454 engine I would leave the torque converter and shift points alone. For a torque engine they would be about perfect now with the settings from the 6.2 diesel. You will be using a vacuum modulator and that can be adjusted if you need a little more speed before shifts.

 

[CuCv M1008]

1965-1991 big blocks are "mark 4" they have provisions for a mechanical fuel pump. 1991-1995 are "gen5" No provisions for a mechanical fuel pump. 95 and later are "gen 6" HO 454 and the L19 replacement blocks have the boss. I think you would be better off using the th400 in your truck, you could bolt up a transfer case to the th400 on the 454 but you would have to change a few things to make it work, imho more trouble than its worth. There are different stall ratings for torque converters gas or diesel, truck or car but as rusty said you should be fine. Hope this helps! Good luck and please post updates as I'm interested in putting a 454 in my truck down the road.

 

[rustystud]

View attachment 6447601965-1991 big blocks are "mark 4" they have provisions for a mechanical fuel pump. 1991-1995 are "gen5" No provisions for a mechanical fuel pump. 95 and later are "gen 6" HO 454 and the L19 replacement blocks have the boss. I think you would be better off using the th400 in your truck, you could bolt up a transfer case to the th400 on the 454 but you would have to change a few things to make it work, imho more trouble than its worth. There are different stall ratings for torque converters gas or diesel, truck or car but as rusty said you should be fine. Hope this helps! Good luck and please post updates as I'm interested in putting a 454 in my truck down the road.

I almost went with a 454 engine in mine, but the lack of fuel economy made me go with the 383 Hi-Torque instead. My best friend has the 454 and he gets 8 miles a gallon. Towing or coasting down a hill only 8 miles per gallon ! He was the one who convinced me in the end. I really liked the idea of all that power but really the 383 does a fine job and compared to the 6.2 diesel it was a big upgrade in performance ! On our last trip towing the RV trailer to the "Gorge" concert I got an average of 15 miles per gallon ! That's going up and over the "Snoqualmie Pass" which is over 3,000 ft , and I maintained 50 mph doing it ! Not bad for a M1028 towing a RV trailer ! Of course the 454 could do it at 60 mph without any struggle but at 8 mph !