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post #1 of (permalink) Old 04-29-2002, 04:03 PM
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Need Advice for Diesel to Gas Swap

I just bought an '87 Suburban heavy half-ton with a 6.2L diesel engine. I'm going to replace the diesel with a gas engine and I need some help from some people who know. I'm going to upgrade to 1-ton axles and hopefully ARB air lockers and plan to run 38" or 39.5" tires. With the big tires, I really want to swap in a big-block, but here's where I need some advice...

Buying a good 454 is a pretty expensive endeavor. I have a couple Olds 455 engines and here's what I was thinking... weren't the early diesels actually Olds 350 motors coverted to diesel? In that case, did the trannys have the BOP bolt pattern? Can anybody tell me the specifics about the tranny and transfer case used in those trucks with the early diesels? I think it might be a lot cheaper to buy a tranny and t-case that I could use with a 455 Olds than to find and buy a good 454.

I also have a couple TH400s and one TH350 with the BOP pattern. It would be nice if all I had to do was find the right transfer case, but I know things seldom work out that nice. Any help will be greatly appreciated. Thanks in advance.

-- soon to have a good 6.2L diesel for sale
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post #2 of (permalink) Old 04-29-2002, 08:06 PM
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Re: Need Advice for Diesel to Gas Swap

Personally, I would talk to the foks at Pennisular Diesel about a dual turbo 6.5 putting out 400 hp and 600+ ft lbs of torque. And still have fuel mileage! Proabably the same overall cost as swapping out to a guzzler!
post #3 of (permalink) Old 04-29-2002, 08:22 PM
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Re: Need Advice for Diesel to Gas Swap

Thanks blt2ski, but actually it wouldn't. I already have the big-block Olds and possibly a tranny that might work, so the Olds swap will be cheaper (I hope.) Any money that I can save will get me that much closer to 1-ton axles and out on the trail If I could do anything I wanted, I'd put a 454 or a 502 in it, but I can't.

I'm hoping someone knows something about what was behind those early diesels... anyone? [img]images/icons/smile.gif[/img]

Thanks for the suggestion, blt2ski. I'm sure that's a great setup, but also way out of my budget. Twin turbos??? What does something like that cost anyway? I'm off to find out!
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post #4 of (permalink) Old 04-29-2002, 11:18 PM
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Re: Need Advice for Diesel to Gas Swap

Howdy, my 82 3/4 ton Chevy was originally a 6.2 diesel, my understanding was that it was a Chevy 350 with dieselized heads and intake, I may be wrong! When my 6.2 gave out on me, I had a Goodwrench 350 with about 18000 miles on it in my hammered 78 blazer, it was actually an easy swap. My truck has the Turbo 400 tranny and 208 transfer case, everything bolted up just like it was meant to! Keeping the Hydro-boost brakes was a guessing game though, kept me up late many nights trying to figure out why they wouldn't work! My suggestion would be to sell off your engine and buy a good 350, the Goodwrench is usually less than $1500.00 and makes a great truck motor!
post #5 of (permalink) Old 04-30-2002, 03:21 AM
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Re: Need Advice for Diesel to Gas Swap

<font face="Comic Sans MS">The 6.2/6.5L are in no way related to the Olds. They're a detroit diesel design. That olds 350 converted to a diesel can be converted to gas I believe if you can dig one up. I believe you can overbore it a fair amount, etc... I recall hearin' about a kit like that.

I think if you're going to swap something in, and would need a tranny adapter anyhow, I'd personally probably go with the 500 cuibc inch caddy engine... [img]images/icons/crazy.gif[/img]</font>
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post #6 of (permalink) Old 04-30-2002, 07:04 PM
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Re: Need Advice for Diesel to Gas Swap

Cool, thanks for the replies

Utwheeler, that's food for thought. I really had my heart set on a big-block though... an olds 455 will put out just a squeek over 500 lbs/ft of torque. While I was searching this forum I saw quite a few references to large diameter tires needing a lot of torque, especially for mudding. A 350 does fine for you, huh? Maybe a big-block would be overkill, I dunno... I would still prefer one, but I may have to get a 350 instead to save money. Thx man.

Tim, I'm pretty sure we're both right about the Olds diesel thing. I have a friend who says his brother had one stock in one of his old Chevy PUs, so that's why I was pretty sure they existed. To make sure I snagged the following quote from the Olds FAQ at

"Diesel production continued until 1985 when all diesels were discontinued for the 1986 model year. Diesel parts were being handled by Detroit-Diesel-Allison, and not Oldsmobile. Both AC-Delco and GM Goodwrench rebuilt 350 diesel engines are available. In terms of rebuilding, try a competent diesel truck mechanic. Olds diesels were also used in Chevy trucks."

So it seems like they were Olds diesels, but the parts were handled by Detroit-Diesel-Allison. That's pretty cool, I didn't know that. I guess the early olds diesels were pure junk from what I've read.

And finally, thanks for the GREAT idea of using a 500 Caddy motor, they're cheap and they'll bolt right in without much trouble I think. I've never looked at one, but they have the chevy tranny pattern, right? Awesome idea. Thanks a lot! [img]images/icons/smile.gif[/img]

BTW, want some interesting (or not) trivia related to the diesel overbore? "The 350 diesel block with a 425 crank and the stock bore size block (4.057") will yield a bulletproof 411 CID small block. The 350 diesel block can be safely overbored .125" without sonic testing, to make a 437 CID small block. The 350 diesel block can be bored out to 4.25" when sonic tested. With a shaved down 425 crank and a 3.975 stroke, that works out to 451 cubic inches." And... "The diesel mains have all the metal of a solid-web block, plus all the metal that should have gone in those windowed-main gas blocks. Pretty hefty. Good for nitrous and turbo/super charger applications. The crankshafts are supposed to be nodular."

Thanks for the info guys, I'm still interested in what was behind the Olds diesels in Chevy trucks... especially the bolt pattern of the tranny.

post #7 of (permalink) Old 05-05-2002, 10:26 PM
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Re: Need Advice for Diesel to Gas Swap

i have both a 6.2 and a 6.5turbo and i love the 6.2 for the milage and love the 6.5 for the power. I also have a dodge cummings and its awsome it just so freakn heavy in the front! If u still have the old tranny from the 6.2 it should hook right up to the 350. The r pretty much the same.
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