Olds 350 diesel to sbc swap

Ricko1966 said:

Just hook everything up as normal,leave your selector valve set to drivers side tank. When to run the passenger side tank syphon the diesel ad a couple of gallons of gas drive it a couple of days syphon it again. Fill it,done.

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Thanks, really appreciate the help

Strick said:

Welcome to the club fella. I just passed up a Canadian GMC that was a 5.7 diesel. Good luck in your swap & daily driver.

HS

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Thanks! Where abouts are you located, don’t see many 5.7 diesels left. Mine was actually made that the Oshawa Ontario plant a few minutes from where I live. I’ve yet to see another one so far (just curious where you saw it)

I'm in central NC. This truck I looked at was a loaded Sierra Grande. All power, tilt, cruise. It had a Starburst in the door with Canada inset. I passed on it due to price & condition.

HS

Strick said:

I'm in central NC. This truck I looked at was a loaded Sierra Grande. All power, tilt, cruise. It had a Starburst in the door with Canada inset. I passed on it due to price & condition.

HS

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That’s hilarious mine is a loaded sierra grande with all the same options, I only bought mine due to how unique it was and the body was immaculate knowing the how bad the motors could be but was still worth the price I got it for

Nice truck, man! Welcome from Wisco!

Welcome from Austria. Nice truck. Remove diesel, fill up with gas. Done.

Ryanbrown36 said:

Hi guys, I’m looking for some help on my olds 350 diesel to sbc swap, I have completed the swap and will be starting the truck up soon but have some questions about the tank situation. I have a dual tank setup and replaced the driver side tank with a new one to make sure there was no diesel left but my old passenger side tank is still on the truck and would like to know if I should plug that off somehow and where it’s best to do so(my fuel lines are All fresh from the new tank to the motor) for reference I’m 17 and have been doing this by myself so might be a dumb question but don't really know what I’m doing and want any old diesel getting in my fuel system. Thanks in advance

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If it is only a few gallons, it won't hurt. Just fill it up with gasoline. After you run one tank of gas through it, it will be free of all diesel.

J. B.

Ryanbrown36 said:

Hi guys, I’m looking for some help on my olds 350 diesel to sbc swap, I have completed the swap and will be starting the truck up soon but have some questions about the tank situation. I have a dual tank setup and replaced the driver side tank with a new one to make sure there was no diesel left but my old passenger side tank is still on the truck and would like to know if I should plug that off somehow and where it’s best to do so(my fuel lines are All fresh from the new tank to the motor) for reference I’m 17 and have been doing this by myself so might be a dumb question but don't really know what I’m doing and want any old diesel getting in my fuel system. Thanks in advance

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Too bad you have already done the work. I would have suggested that you replace the heads and intake with Olds 350 gasoline heads and intake. That 350 diesel, as bad as it was, is indestructible when converted to gasoline.

J. B.

JBswth said:

Too bad you have already done the work. I would have suggested that you replace the heads and intake with Olds 350 gasoline heads and intake. That 350 diesel, as bad as it was, is indestructible when converted to gasoline.

J. B.

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I did look into this before my swap although this motor swap already has me in over my head as I don’t have anyone to really help so it’s all what I can find on the internet. Would’ve been sweet to do it though.

'81 350 diesels are rare birds! That is a cool pickup. I looked at an '81 Chevy in here in ND last year that was for sale. Also needed an injection pump. I passed on it though as a previous owner had mounted a cb radio mount to the celing and bolted it through the roof. Was pretty tempting though because of how rare they are. They have simple "diesel" badges on them that are different from the '78-80 diesel pickups.

mcarlo86 said:

'81 350 diesels are rare birds! That is a cool pickup. I looked at an '81 Chevy in here in ND last year that was for sale. Also needed an injection pump. I passed on it though as a previous owner had mounted a cb radio mount to the celing and bolted it through the roof. Was pretty tempting though because of how rare they are. They have simple "diesel" badges on them that are different from the '78-80 diesel pickups.

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Yes they are definitely pretty rare now, partially why I bought it as it was a little different than all the other squares out there, and the body is basically perfect. I’m 100 percent leaving on the diesel badges bc I like how they are unique.

Man, I'd disconnect that tank, which I did on my '78, and replace the rubber fuel lines where ever they are. That old rubber wasn't made to run the newer low sulpher fuel through them. I'm positive that they are deteriorating inside and will become an issue at some point.

SDTECH1 said:

Man, I'd disconnect that tank, which I did on my '78, and replace the rubber fuel lines where ever they are. That old rubber wasn't made to run the newer low sulpher fuel through them. I'm positive that they are deteriorating inside and will become an issue at some point.

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I think you’re confusing ethanol in gasoline degradation of older soft parts with ULSD which has less lubricating ability than LSD which was the standard before ULSD.
That said, yes I’d replace every soft hose in the fuel, brake and cooling systems as you have the opportunity to. No matter how well the truck was kept, even though it’s obviously pristine condition, what he ^ said is correct. It’s old rubber and will be an issue tomorrow or next year maybe….
Even if it works now, sounds like the truck sat for a while before you? Now that you’re going to be exercising it frequently any weak pieces will step up and take a crap randomly, imo.
And since it sure don’t need any beautification work, you can concentrate on all the mechanical stuff.
Looking back at your pics again that is literally one of the nicest original old squares out there!

@Ryanbrown36 beautiful truck! Wow! That was either someone’s local garage queen or it didn’t live up there most of its life.
And even moreso, amazing you’re doing all this work at your age, especially on your own. Me and my buddies were the same at your age, but our collective knowledge combined with dads and grampas knowledge and help was key. Although the internet is a great resource, I had an “Andy”. My grampas buddy who knew “everything.” He was like a 1970s and 80s Google for all things auto repair related! Very influential person in my life back then.

Back to the fuel thing, agree that selector looks unique for sure. But does it work? If it works, and you said you verified it’s switched to the tank you want to use initially, I’d just fill it with gas and send it!
Regarding the off side tank, if the fuel pickup and filter sock from the tank you removed was ok, I’d presume the passenger side is similar condition.
As said, siphon or pump out as much old diesel as possible and put gas in it. Or just wait til you have more time and drop that tank and empty/clean it and run off your new tank only for now.
Kind of depends if both senders and switching valve work or not imo.

Fwiw we once proved that a Mercury marine V6 will run on approximately 2/3 gas 1/3 diesel. Back in the day a dock helper filled his boat with diesel at the fuel dock. No one knew it until the boat died. We were on vacation and time was of the essence so we towed it back to the resort, put it on the trailer, siphoned as much diesel out as we could. Guessed it was 2/3-3/4 of the tank. Topped it off with premium and it ran. Smoked like hell the first day. Topped off with gas again, less smoke then, but it did no damage other than the weirdest exhaust smell ever and the fact it was a mosquito fogger for a couple days.