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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: okiesinmt on December 21, 2009, 12:59:30 pm

Title: changing from a diesel to a gas engine
Post by: okiesinmt on December 21, 2009, 12:59:30 pm
How hard is it to change a truck from a desiel to a gas engine?  How many systems have to be removed and added?  Just wondering cuz this is a nice looking truck.

http://larrystractorstrailersandmore.com/images/GEDC1446.JPG

Thanks
Sean
Title: Re: changing from a desiel to a gas engine
Post by: zieg85 on December 21, 2009, 01:28:40 pm
With a start like that I would do it.  That is a nice looking Shorty.  I only converted one diesel in a 1980 Olds Delta 88.  Swapped in an olds 350, the only issue I had was I had to vent the gas tank.  Everything else went fairly simple as I recall.
Title: Re: changing from a diesel to a gas engine
Post by: VileZambonie on December 21, 2009, 03:42:04 pm
My 1980 was a 5.7L Diesel converted to gas (400)...I miss that truck...

You can eliminate the glow plug system, drain and flush the fuel system, get some motor mounts, the rest is plumbing, wiring, exhaust, nuts n bolts. Would you carburete it?
Title: Re: changing from a diesel to a gas engine
Post by: okiesinmt on December 21, 2009, 07:51:52 pm
I don't know I am totally unfamiliar with a desiel.  What would be my options?  Is it a 400 block that can be converted to gas?  I converted my 76 400 to mpi fuel injection.  Is it basically the same conversion?

thanks
Sean
Title: Re: changing from a diesel to a gas engine
Post by: 81C20 on December 21, 2009, 09:05:31 pm
Sharp truck! Does it have the 5.7 or 6.2 diesel? Either way, I'd leave it (I'm partial to compression ignition though ;D ). Despite the bad rap on the 5.7's, upgraded head bolts, a water separator, and good fuel (plus maintainence) and it'll last. The 6.2's are durable, although slow. 
Title: Re: changing from a diesel to a gas engine
Post by: VileZambonie on December 21, 2009, 09:11:32 pm
No, you would just want to get a gas engine if you are going to do the conversion. I just picked up vortec roller 350 motor for $100 bucks on craigslist. I think I'll save this one to make into a stroker. But there's plenty of gas engine options just figure out what you want and start lookin around.
Title: Re: changing from a diesel to a gas engine
Post by: okiesinmt on December 21, 2009, 09:12:51 pm
Its a 6.2 with 143,000 on it.
Title: Re: changing from a diesel to a gas engine
Post by: VileZambonie on December 21, 2009, 09:13:58 pm
If it's a good runner you can sell the diesel too to fund your project.
Title: Re: changing from a diesel to a gas engine
Post by: okiesinmt on December 21, 2009, 09:16:39 pm
So I could pull the 400 out of my rusty body and put it in the new body?
Title: Re: changing from a diesel to a gas engine
Post by: VileZambonie on December 21, 2009, 09:17:53 pm
yeah
Title: Re: changing from a diesel to a gas engine
Post by: okiesinmt on December 21, 2009, 09:23:26 pm
So what price would be fair to offer this guy for this truck, I know it differs by area but whats your opinion?

Thanks
Sean
Title: Re: changing from a diesel to a gas engine
Post by: Mr Diesel on December 22, 2009, 08:09:06 am
Why not leave the 6.2 in it? Should get well over 20 mpg in a light truck like that.
Title: Re: changing from a diesel to a gas engine
Post by: dusty82 on December 22, 2009, 11:18:58 pm
Just finished doing my 82 4x4. Not hard at all, biggest challenge was to eliminate all the extra wiring. Went to salvage yard and retrieved a couple of extra engine harnesses for the wires I needed. Get a maintence/repair manual and go at it. I've had my truck since early '84, has 130K miles on it and the crank broke, never could stand the noise. Now with the sound insulation and a 350, it will be as quiet as a funeral parlor!!!!
Good luck.
Title: Re: changing from a diesel to a gas engine
Post by: Camfirchev on December 23, 2009, 03:08:35 am
Way sweet truck!   I have done 5 of these conversions.  I have a list of every single part if needed, right down to the last nut and bolt.  Just a few FYI's to toss around before you make a decision,  Change the Torque Converter over to a gas Engine Converter. (The diesel has a much lower stall) Swap out the hydroboost Brake Booster for a Vacuum style.  Swap out the AC compressor to the short version used on the gas motor. (It will save you a ton with fuel mileage with the AC on)  Also BB chev bolts directly up to the factory exhaust,  but the SB chev will have to be changed on one side of the Y pipe.

As for the Electrical.. all the wires are there they just need to be rerouted to there new locations.  I have a pin out diagram to use the factory bulkhead from the firewall. (Gas electrical harness will not interchange over to the Diesel bulkhead.. Your better off to remove what is not needed from the Diesel Harness)
Title: Re: changing from a diesel to a gas engine
Post by: Captkaos on December 23, 2009, 12:36:37 pm
You don't HAVE to change out the Hydroboost, unless you want to.