Not a Duramax but a repower for sure

[DAVe3283]

My brother and I picked this up yesterday:

It's a used GM 8.1L truck engine, has about 90k on the clock, with good compression. We paid $450, plus about $50 in fuel to go get it. Seemed like a good price to me!

It is going to be used as a long block for this:

That is a Mercury MerCruiser 496 Mag HO (425 horsepower) boat motor. Got that for free (yes, free) with the fuel pump, ECU, harness, and tons of parts. It started life in a barge (IIRC), but within 10 hours it threw a connecting rod and windowed the block. Factory decided it was cheaper to put a new engine in than to fix that one, and they left the bad engine with the boat owner. The owner didn't need it, and gave it to to us

Our plan is to swap the cam, intake manifold, fuel system, and electronic controls over from the toasted marine block to the one we just picked up. Add a flex plate, and a few other details, and we hope to put it in this:

That is my '82 Chevrolet C10 Silverado, currently with the factory 6.2L diesel. My Grandpa bought it new, and I inherited it from him. Over the years, it got fitted with a 4.11 rear end and Detroit TrueTrac locker and a fully built 700R4 automatic (it should hold up to the 8.1L).

I'll try and put up photos and videos as the project progresses. Our goal is to have this done by the end of June, and with a total budget of less than $1,000. Hey, we can dream, right?

 

[duramaxxin]

That 496 is about 10k a piece. Used to have a pair of them in my old boat. Nice find.

 

[THEFERMANATOR]

http://www.azspeed-marine.com/

Send your ECM off to these guys so your not stuck with a marine cam that won't want to wind up very high and be limited to about 5200 RPM's. They can take just about any of the GM MEFI systems that MERCRUISER used and custom program them for just about anything. Plus they'll be able to disable any of the safetys in it that might pop up from the swap as most of the late model marine engines monitor water pressure from the raw water pump.

 

[Diesel Pilot]

That truck is in ridiculous condition! Wish I could find one just like it but 4wd.

Good project, should be amazing when it's finished.

 

[JMDuramaxLB7]

That 700r4 will not be long lived behind that if you abuse it any.

 

[carter_44]

Nice project Dave. When is the Dmax going to get some more love? I though we were talking trans, lift pump etc. a year ago.

 

[DAVe3283]

That 496 is about 10k a piece. Used to have a pair of them in my old boat. Nice find.

Thanks! Yeah, if it wasn't under warranty, the factory said a replacement would have been 12k!

http://www.azspeed-marine.com/

Send your ECM off to these guys so your not stuck with a marine cam that won't want to wind up very high and be limited to about 5200 RPM's. They can take just about any of the GM MEFI systems that MERCRUISER used and custom program them for just about anything. Plus they'll be able to disable any of the safetys in it that might pop up from the swap as most of the late model marine engines monitor water pressure from the raw water pump.

That's good to know, if we can't get the marine ECU to be happy in a truck. We might just put a truck ECU on it and I'll EFILive it into submission. Really depends on what is cheapest, this is a "budget" build (we'll see how that goes).

That truck is in ridiculous condition! Wish I could find one just like it but 4wd.

Good project, should be amazing when it's finished.

Thanks, we've tried to keep the truck in good shape. Once the drivetrain is complete, we'll start saving for minor body work and a nice paint job. Yeah, the truck should be nuts with an 8.1L in it.

That 700r4 will not be long lived behind that if you abuse it any.

Honestly, I am with you. However, the shop that did the transmission swears it will hold 450-500 HP. It does have a lot of good parts, but the 8.1L is a torque monster. Here's hoping it holds!

Nice project Dave. When is the Dmax going to get some more love? I though we were talking trans, lift pump etc. a year ago.

The Duramax is going to get some love here shortly, I promise! I have been (slowly) putting money into the trans fund--that's the big hurdle. I'll probably spend more on the Allison than for this whole conversion... The trucks each have their own "fun" account, so this isn't delaying my plans for the Duramax any. The 8.1L is getting funded by both my brother and myself, so it will go quicker than my truck.

 

[Big Block 88]

It isn't HP that kills tranny's man, it's the TQ and you will be makeing alot of it.

 

[TIM Z]

Nice project!!

That 8.1 will be badass in that ole' chevy!

The best of both worlds, old school body style, modern power !!!

 

[DAVe3283]

It isn't HP that kills tranny's man, it's the TQ and you will be makeing alot of it.

Yep, that I will! I agree that torque is the killer:

...It does have a lot of good parts, but the 8.1L is a torque monster. Here's hoping it holds!

I've got my fingers crossed on the trans holding up. Time will tell.

Nice project!!

That 8.1 will be badass in that ole' chevy!

The best of both worlds, old school body style, modern power !!!

Thanks! I personally like the '82 body style better than my '03. I am pretty excited about this project

 

[SmokeShow]

how'd this turn out over a year later?

 

[DAVe3283]

Man, almost forgot about this thread. It's been a crazy year. I ended up changing jobs and moving 400 miles, which pretty much stopped all my projects. However, it should be picking back up here in a week or two. I love the new job, but wish I had more free time...

What looks like will happen, is once the 8.1 is together (hopefully early-to-mid August), a friend wants to stick it in his boat. In return, he'll pick us up a GM 6.0L gasser (with all the electronics), and parts/labor for everything. My brother has a cam, valve springs, and a bunch of other goodies for a 6.0L. When all is said and done, the 6.0L should make similar power (plus I can tune it with EFILive, where the 8.1L uses a marine ECU).

Worst case, my friend changes his mind on the 8.1L, and I stuff it in the truck like I was planning :thumb: So stay tuned for some updates in the coming weeks. For real, this time :doh:

 

[duratothemax]

I say go with the 6.0 in the old truck, for sure. The 8.1's are decent stock towing engines, but otherwise they are boat anchors. The aftermarket performance scene for them is basically raylar and...............? nothing.

You'll put 5x as much $$ into performance stuff for the 8.1 and not even go twice as fast as a 6.0.

If you want a fast fun truck that really rips for minimal effort put into the engine, the 6.0 wins all day long.