Thinking of going back to a gasser

[tanman_2006]

Some back story

The Dmax is breaking the bank, 14.5mpg average, 3.79/gal diesel, and $600 payents/mo dont mesh when gas is 2.89, propane is 1.48 and an old TBI can do most of what I need on the day to day and the 6.5's can actually out pull my dmax when it comes to not overheating. Been stealing my wifes 03 to DD and the cost/mile is awesome even at 9.5mpg. At other sites (GMFS) you tend to get the 6.0L swap answer anytime you post, if I wanted a 6.0L I would buy another 6.0L not swap one in (not cost effective) so I thought I would post questions in a place that appreciates the old TBI.

I owned a 89 C 2500 350 ECLB 4 speed custom intake and throttle body (installed before I bought it 11yrs ago) rolled it and bought a 95 K1500 305 ECSB bought it w/ 80K and sold it 8yrs later w/ 257K over 20mpg average 3.42's and gutless.

So now we come full circle and I cant afford to use a diesel sucking dmax as a feed truck: its too nice, worth too much, and costs too much to repair. Now a 91-95 350-454 K3500 w/ a propane kit would be cost effective, cheap to repair, and I wont feel so much like I am beating a cadilac.

I have found a 94 K3500 350 NV4500 already has a bale bed, rebuilt engine, synchros, and clutch. My neighbor also has a BEAT UP 96 K2500 Vortec 350 GM Drop in 4l80 Bale bed (I want it for parts). Propane kits are only made for Carb's, 87-95 TBI, and 98-'14 6.0/8.1L.

Now for the questions:

I will be towing and hauling weight frequently, a 383 or 454 would be the best choice I am sure. Working with the 350's I was thinking I could set the current engine in the 94 up how I want as far as TBI mods, fuel pump, pressure spring, and other basic bolt on mods. In that time I thought the 96 Vortec would make a good 383 canidate and have everything ready for a torquey workhorse.

I dont thing underdrive would be a good idea idling in pastures.

Is the 96 a good engine choice? Where would I get a 383 kit? Cam specs for a 383? Recommended TBI/Intake Mani? Who makes good tunes? Cooling upgrades? Ignition?

Other than that I will go catless, Y Piped, shorties or mids, open air filter, 6.5L oil cooler, possibly 4.56 gears, and 33" tires

Further more, anyone on here run on propane?

Truck will be used for general farm and ranch use. I have a custom farming, hay, tree cutting, light dozer, and consulting buisiness. I put ~60K/yr on my trucks combined and typically only have 2-3 running at a time.

 

[Tuck]

....damn....by the title I thought we were gonna talk about nostalgia drag racing....carry on....

 

[tanman_2006]

No but it got a bump out of you! lol

 

[tanman_2006]

Wow, I'm overwhelmed with all the advice on if I should keep the 350, build a l31 383, or go 454.

If I stay 350, what set up will get me the torque I need?

If a 383 would be a good workhorse, where should I get the kit?

454? Where do I get the extra fuel tank? Lol

Source Unknown

 

[gmcyukondriver]

Might want to check the sarcasm and remember how much guys on this site are getting paid for their advice.

How much weight do you tow on a regular basis?

Also keep in mind that gears have a big influence on how a truck feels when driving/towing. 3.42's that you had along with your 305 would basically be a fuel mileage setup in my mind. Some 3.73's or 4.11's would definitely change how the truck feels.

We towed a 4500 lb (dry) trailer with my truck for several years. This included hilly and mountainous roads, and the 350 did fine for our purposes.

I don't know too much about the Vortec blocks, or if certain years are better than others. I will tell you that if you're keeping the TBI setup with a 383, you would need either the GM Performance TBI to Vortec Intake: http://www.summitracing.com/parts/nal-12496821/overview/make/chevrolet

or

You can get a carbureted intake for a Vortec, and then use a TBI adapter plate. It's your choice.


As far as keeping the 350, or swapping engines, it kind of depends on your budget. All of them can be made to be torque monsters, it just depends on how much grunt you actually need for towing, and what your budget is.

 

[tanman_2006]

Might want to check the sarcasm and remember how much guys on this site are getting paid for their advice.

How much weight do you tow on a regular basis?

Also keep in mind that gears have a big influence on how a truck feels when driving/towing. 3.42's that you had along with your 305 would basically be a fuel mileage setup in my mind. Some 3.73's or 4.11's would definitely change how the truck feels.

We towed a 4500 lb (dry) trailer with my truck for several years. This included hilly and mountainous roads, and the 350 did fine for our purposes.

I don't know too much about the Vortec blocks, or if certain years are better than others. I will tell you that if you're keeping the TBI setup with a 383, you would need either the GM Performance TBI to Vortec Intake: http://www.summitracing.com/parts/nal-12496821/overview/make/chevrolet

or

You can get a carbureted intake for a Vortec, and then use a TBI adapter plate. It's your choice.


As far as keeping the 350, or swapping engines, it kind of depends on your budget. All of them can be made to be torque monsters, it just depends on how much grunt you actually need for towing, and what your budget is.

Sorry but I am used to atleast a suggestion after a day or 2.

My work trucks are tagged for 36,500 if that gives you an idea and I have been shut down for being over weight. I dont get much over 50-55mph when loaded to the hilt.

I can get the whole running 96 K2500 truck for cheap. If the vortec 350 built to a 383 would be a good idea I will start a build on it but it will be about a yr before I finish (i take my time). I would like to start with exhaust and engine mods on the stock tbi engine, when it comes to TB mods keep in mind I still need to add a propane induction plate under the TB.

Like I said 4.56's are a possibility, I understand the concept of the steep gear in my 1500 for mpg vs sticking 4.10's or 4.56's on a tow rig. My 89 was a beast, would tow anything.

One of my biggest concerns is over heating

 

[gmcyukondriver]

Ok, as far as exhaust and engine mods on the stock TBI, I would take a look at just making it breathe easier.

From what I've seen, shorty headers or mid-length are better for low-end torque, along with an 'H' pipe and dual exhaust. 2.5" should be fine. On the intake side, Edelbrock is one of the few companies that makes a performance TBI intake, or you could get a carbureted intake and just use the TBI adapter plate. That would probably be easier and cheaper, since those intakes are easier and cheaper to get your hands on.

I'm not really familiar with running propane, but I would definitely recommend this thread: http://www.gmt400.com/forum/showthread.php?11743-ULTIMATE-TBI-mods-stage-1

How tall is the TBI adapter plate? Are you going to have any issues with clearance of a stock hood?

Also, from what I've read, most people tend to give the TBI heads a bad rep. They can actually be opened up quite a bit to flow some decent (not great, but not terrible) numbers. Depending on what that costs, it might just be easier to get a set of vortec heads and run a vortec intake, that way you would already have the intake setup for when you finish the 383 build.


As far as cams go, I can't help at all. I don't know much about cam profiles, but I'm trying to learn. Hopefully someone with a bit more experience in these areas can chime in. I know a guy with a Vortec 383, I'll tell him to get in here so he can tell you what parts he used for that build.

 

[Darkrider]

Bear in mind you usually loose about 10-15% of your HP with running with propane so factor that into your mod ideas to make sure you get the power you want. It may need a hotter cam..or higher compression pistons..etc basically build the engine a bit hotter then you would need if it was a gas powered engine to get around the power you want on Propane.

 

[tanman_2006]

Thanks for the input.

There are alot of people/farmers running propane around here nothing new. I know a propane kit on a tbi 454 raises the intake enough it can rub the hood under high torque app, taller filters can guarantee that. So if a carb intake w/ added adapter is taller than the vortec/tbi gm performance manifold or similar from edelbrock then it's out.

This truck will for all intensive purposes take the place of my dmax (not in power but as a multi use truck).

Source Unknown

 

[tanman_2006]

Point taken on higher compression but I do run on gas too, high 9's wouldn't be a bad idea though. On my engine build or heads that I build for the truck I will upgrade the valve seats. I know propane need hardened valves and seats, just not sure if any high horse kit will work or if I need propane specific kit.

Thanks for the idea on compression, I will be sure and bring that question to light once I get started.
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