1994 GMC sierra TBI mild build.

[LessThanClaypool]

New to the site! I've got a mild build 350, its in a 1994 GMC sierra. Some stainless headers and she runs pretty good. Burnouts on command are pretty dang nice. If there is any interest in the modifications I'd be happy to elaborate. Looking to buy a 6.5 diesel version of this truck, or even trade with cash on top. Looking to use the green pump at the gas station lol. How does the 6.5 Detroit compare to the 350? Pros and cons would be amazing.

 

[WarWagon]

Burnouts? Wrong econo diesel to want to do that with. Not unless you want to spend a lot on performance or stall it with a higher RPM converter.

 

[Chewy1576]

Hard to compete with the trusty old Small Block Chevy in this generation of trucks when it comes to reliability and just putting power to the pavement. Why the switch? Not trying to discourage you, just wondering what your plans are. I have one with a 6.5L and another with a 383. I enjoy both of them for different reasons.

 

[LessThanClaypool]

Mainly gas mileage is my reasoning. I get 11-16 mpg with that 350. Not looking for burnouts, just looking for offroad torque, and good mileage.

 

[btfarm]

Welcome to The Truck Stop! Nice looking truck and SBC. I made your pictures full size.

 

[Will L.]

Welcome.
You can have mpg OR power. Choose wisely Danielson.

You can get good mpg and good power if you are willing to invest ten grand. 4 grand you can one or the other.

 

[WarWagon]

Mainly gas mileage is my reasoning. I get 11-16 mpg with that 350. Not looking for burnouts, just looking for offroad torque, and good mileage.

You have to have a special place for this engine in your heart and a deep pocketbook doesn't hurt. Otherwise your 350 STOMPS it into the scrap pile in every way imaginable.

Maybe some other vehicles you can consider like a H3 5.3L V8 Alpha edition that gets 18 MPG and is very capable off road. Budget? Get the 5 banger and make sure it's the low gear ratio transfer case. AKA off road package.

You would be lucky to get anything over 14 MPG with these bean counter cheap expendable diesel engines. Diesel costs more, takes more oil on short change intervals, and fuel filters... IF nothing expensive goes wrong. Go ahead and name ONE single cheap repair on this engine. Good parts are getting hard to find. MPG is a LIE when you look at TCO. @Will L. is NOT kidding about burning a pile of cash to overcome GM's bean counter touch on this engine.

So how do you feel about yanking blown engines? You got a stupid simple dead reliable 350 that you can't hardly hurt. Overheat a IDI diesel once and it's likely toast. Overheat means going over 210 not pegging the temp gauge. Peg a temp gauge on an IDI diesel and the heads crack for real and rings are ruined. IF and only IF the engine doesn't find a way to commit suicide first like eating a glow plug as derbis. Your 350 starts, period. IDI diesel: Bad one of two battery, bad starter, air in the fuel line and you are making repairs not going anywhere.

My dad said of the first glow plug munching 6.2 diesel we had (A 6.5 is just a bored out 6.2) "I could buy a tanker truck of premium gasoline for the repair costs of this 1988 6.2L diesel." Even the IRS questioned the truckload of parts we put on the 1993 6.5TD. Could own a Truck Stop now instead...

Just saying go out and put a super charger kit on that 350 and burn the premium gas. And still be money ahead.

 

[Will L.]

@WarWagon may be on to something here. A turbo charger on your 350 and wmi kit means you could pull similar power and up your mpg. Save a lot of cash in the process.

I’ve seen sooo manyyy people yank a gas and drop in diesel- it’s better to buy a diesel truck and refresh the engine. Then sell the gasser.

 

[LessThanClaypool]

I've got two gassers. Would selling one for a diesel be good? I have my heart set on diesel, my degree is in diesel. Slapping a turbo on TBI is a whole BUCKET of worms, and I really dont like the sound of those crawling around with my daily driver. And in order to keep my trans (4l60e) I need to have the TBI talking to the transmission. I see the 6.5 is less reliable, a lot less. Now I'm a bit leery of them.

 

[WarWagon]

Yeah, Not a good first diesel to learn on.

If you want a diesel get a diesel that up to the reputation of a diesel. Duramax 6.6L, (Avoid the LLY Duramax trouble) Cummins, some foreign makes. Nothing with a cheap CP4 POS high pressure pump.

Many complete supercharger or turbo kits that play nice with the OEM trons like the trans out there. Or screw it and put an aftermarket shift controller on it.

 

[ak diesel driver]

So the other side of this is my 96 died at 306000. Biggest issue is most mechanics don't know what thy're doing with these engines. They are quite a bit different than most heavy duty diesels. They like RPM and dislike lugging, no starting fluid to help it start, etc. They can be quite addicting as you can see from this site.

 

[BIGR]

Yeah, Not a good first diesel to learn on.

If you want a diesel get a diesel that up to the reputation of a diesel. Duramax 6.6L, (Avoid the LLY Duramax trouble) Cummins, some foreign makes. Nothing with a cheap CP4 POS high pressure pump.

Many complete supercharger or turbo kits that play nice with the OEM trons like the trans out there. Or screw it and put an aftermarket shift controller on it.

LBZ Duramax, that's the ticket.

No particle filter, no DEF, just that silly EGR to deal with.

Dang good power in stock form: 360 HP and 650 ft lbs of torque.

 

[LessThanClaypool]

I'm trying to stick to the OBS style trucks, and keeping them pretty original. I've got a 305 c1500 long bed, and that 94 K1500 z71. I've seen lots of people swap in a Cummins, but (please don't shoot me for saying this) I like the underdog appeal of the 6.5. I know there are going to be problems. I've got a nice old shop, an engine hoist, and lots of time on my hands, along with lots of diesel techs that live with me, and here in a couple years I'll have my degree in it. I'm pretty stuck on having an OBS with the diesel. I do want to know what the main problems to look out for, and if push comes to shove I can order a whole engine off JEGS or Summit and just keep it running. Id plan to keep it stock, or if I'm feeling lucky maybe a turbo, but no more than 15PSI.

 

[BIGR]

I'm trying to stick to the OBS style trucks, and keeping them pretty original. I've got a 305 c1500 long bed, and that 94 K1500 z71. I've seen lots of people swap in a Cummins, but (please don't shoot me for saying this) I like the underdog appeal of the 6.5. I know there are going to be problems. I've got a nice old shop, an engine hoist, and lots of time on my hands, along with lots of diesel techs that live with me, and here in a couple years I'll have my degree in it. I'm pretty stuck on having an OBS with the diesel. I do want to know what the main problems to look out for, and if push comes to shove I can order a whole engine off JEGS or Summit and just keep it running. Id plan to keep it stock, or if I'm feeling lucky maybe a turbo, but no more than 15PSI.

I got you, don't blame you a bit. I like alot of the old body style trucks better than some of the newer ones.

Those older vehicles bring back alot of memories of when I was a younger Lad.....

 

[LessThanClaypool]

I got you, don't blame you a bit. I like alot of the old body style trucks better than some of the newer ones.

Those older vehicles bring back alot of memories of when I was a younger Lad.....

Is there anything in particular to look out for when I go to pick one up? short of rods hanging out of the pan lol.

 

[BIGR]

Those 6.2 / 6.5 guys will chime in soon, I am sure. I know very little about the 6.5 diesel. They will have some tips and info on what to look out for.

2006 LBZ was the first diesel I ever owned.

 

[ak diesel driver]

There's a military reman on eBay right now for $1500

 

[Will L.]

Figure out the main use and get the right set up from the beginning.
Towing heavy or not? Have to haul large items often or not?

Take the time to learn about 6.2/6.5 and their quirks before buying. Overheating and pmd/ip issues are top of the chart.
If you are good with electronics and willing to buy the needed equipment, learn the system and using a ds4 ip is ok. Otherwise make the smart (imo) choice and run a db2 ip and no fighting the crappy pmd/ds4 system. For pickup trucks that means 93 or older, unless you live where you have no emissions inspection on your diesel- then you can convert the ds4 to a db2.

 

[ak diesel driver]

When looking at a used engine if they won't let you take the pan off to look for cracks, walk away. Cracked heads are common but pretty easy to get reman heads. After you have a good engine the big thing is keeping it cool. Probably more ruined engines from over heat than anything else. If you don't like quirky electronics go mechanical

 

[LessThanClaypool]

Figure out the main use and get the right set up from the beginning.
Towing heavy or not? Have to haul large items often or not?

Take the time to learn about 6.2/6.5 and their quirks before buying. Overheating and pmd/ip issues are top of the chart.
If you are good with electronics and willing to buy the needed equipment, learn the system and using a ds4 ip is ok. Otherwise make the smart (imo) choice and run a db2 ip and no fighting the crappy pmd/ds4 system. For pickup trucks that means 93 or older, unless you live where you have no emissions inspection on your diesel- then you can convert the ds4 to a db2.

Main use is a daily driver, 50 miles a day. no hard use, other than the massive hill I live up. I like going off-road, but mainly light trails and some mud and lots of snow. if I get another 9mpg roll on this small-block my wallet is going to have a heart attack. again, 50+ miles a day. Even having to replace the engine more often I would be saving more than the mileage of the mild 350. Might stab a bigger turbo on, and do the PMD relocate/update if it hasn't already. I have no emissions at all, straight pipes (diesel) are legal and probably likely on this truck if I get one.