I'm sure there are a ton of tips and tricks for improving fuel delivery on your Chevy powered 4x4, from carburetor mods to computer chips to stand alone fuel injection systems. Lets hear what you've done or what you have questions about!

I run a Chevy 421 stroker SB with Propane induction and NOS. I like the propane over EFI because I don't have to deal with electronics and sensors, it's very simple. I use a Impco Model E regulator and Impco 425 mixer with a NOS Pro Shot system on a Victor Jr. single plane manifold. I built the engine with 10.5 to 1 compression to help with the power loss of propane and hardened exhaust valve seats for the higher exhaust temps. I used an MSD box for a more complete burn seeing that propane has a higher flash temp but a longer(slower) burn time then pump gas. The muti-spark MSD setup work great for this.

Um, I turned my q-jet around 180* on the manifold to allow for better uphill fueling. Required a longer fuel line, and longer throttle cable.

I use a TPI TECH harness to install 91 vette tuned port on my 383. Now I have to remember to turn off te truck when I roll onto my side.
Phil

Part numbers and prices to run a carb on a 4.3 Chevy V6.


Edelbrock Performer manifold:#2111 $185.95
Edelbrock Performer 500 cfm carb: #1403 $275.95

MSD Pro Billet distributor: #MSD 8597 $269.95
uses a 6 or 7 series spark box
MSD-6 Offroad Ignition: #MSD 6470 $212.95
Add a coil of your choice.


All prices are right off of the Summit (www.summitracing.com) website. Jegs was four cents higher on all parts.

Originally posted by PYRO
I run a Chevy 421 stroker SB with Propane induction and NOS. I like the propane over EFI because I don't have to deal with electronics and sensors, it's very simple. I use a Impco Model E regulator and Impco 425 mixer with a NOS Pro Shot system on a Victor Jr. single plane manifold. I built the engine with 10.5 to 1 compression to help with the power loss of propane and hardened exhaust valve seats for the higher exhaust temps. I used an MSD box for a more complete burn seeing that propane has a higher flash temp but a longer(slower) burn time then pump gas. The muti-spark MSD setup work great for this.

What does a setup like that go for? There is a truck at U-pull it out here that has that on it. I thought about getting it, but I have no room for a tank. Do you have to build the engine to run propane, or can you just bolt it on?

Edit: I am running a stock Q-jet, nothing special, but...............my float bowl empties overnight. When I go to start it in the morning, it takes forever. How do I fix this?

My roomate just switched over to propane and his motor was build for gas.(normal compression)

I got tired of trying to make my Edlebrock carb work on hills so I took it off and put on a TPI system off a 91 camaro. It was not too hard, and I used all factory parts except the computer chip (flash prom I can re-program on my PC) and fuel lines.

http://coloradok5.com/photos/data/500/87done-med.jpg

It's actually a very simple system, even though I re-used the factory harness and ECM. If you can wire a stereo, than you can wire up an EFI system using a factory harness.

Originally posted by motorhead72k5


What does a setup like that go for? There is a truck at U-pull it out here that has that on it. I thought about getting it, but I have no room for a tank. Do you have to build the engine to run propane, or can you just bolt it on?


Roy's site will give you an idea on prices

http://www.propaneguy.com/default.htm

You can run propane on a stock motor but you will have a very slight power loss, increasing compression will bring the power on again. It will also burn the stock exhaust valve seats but only after about 40K miles due to the high burn temps of propane so hardened seats are a good idea but most people don't bother. Run a single plane manifold, the propane is already a vapor and does not need to atomize like liquid fuel so run it right from the mixer to the valves in the shortest distance, thottle response will be instant.

Originally posted by motorhead72k5
Edit: I am running a stock Q-jet, nothing special, but...............my float bowl empties overnight. When I go to start it in the morning, it takes forever. How do I fix this?

This is more of a band-aid, not a fix... electric fuel pump. My carb does the same thing, and when i turn the key 'on', I hear the bowl gurgling as it fills up... a couple quick stabs at the throttle, turn the key, and she fires right up.

Originally posted by PYRO


Roy's site will give you an idea on prices


Thanks for the info.

Originally posted by Eskimo
This is more of a band-aid, not a fix... electric fuel pump. My carb does the same thing, and when i turn the key 'on', I hear the bowl gurgling as it fills up... a couple quick stabs at the throttle, turn the key, and she fires right up.

I never thought of that. That's a good idea, but I would like to know what to do at the carb to fix that.

One trick I've heard of is if your running an electic pump is to switch it off in offcamber situations and turn it back on when it starts to starve out or when your on level ground.

Originally posted by motorhead72k5
I never thought of that. That's a good idea, but I would like to know what to do at the carb to fix that.


There should be a one way check valve of some sort. Sounds like you may have a leak somehwere. Are you running a mechanical pump? You might have a hole in the diaphram. Check you oil and give it the sniff test. If it smells like gas, you got a hole. You might also install a one way check valve somehwere in the fuel line.

It could also be leaking from the bowl bottom plugs. People often have to put epoxy over the plugs.

I've got an '89 TBI transplant. Nice, cheap, and simple (for EFI) and parts available anywhere. Plus I don't have to track down fuel for refills like the LP guys.

Thanks, I will check those out.

i have the edelbrock 750 trash. runs great and makes lots of power. just as long as your on perfectly level ground. i have heard you can get an "offroad kit" for these carbs that makes them run a little better. but im holding out for the 2003 zo6 at the junkyard(yeah right)

Originally posted by drunkmarine
i have the edelbrock 750 trash. runs great and makes lots of power. just as long as your on perfectly level ground. i have heard you can get an "offroad kit" for these carbs that makes them run a little better. but im holding out for the 2003 zo6 at the junkyard(yeah right)

Yeah, a buddy of mine heard the same thing and bought one. Even with the 'offroad kit' the things runs like crap on anything nose up or down.

I have the Edelbrock Q-jet replacement, and it works GREAT! I have a TBI setup that I was going to use on my burb, but since I would have to re-chip it for the cam I was going to use, I'm just going to stick with this carb and sell the TBI. The Q-jet Edelbrocks rock!

I tried that Edel trash a long time ago. Hated it. Talked to Edel tech and *they* told me the off-road kit wouldn't cut it for rock crawling. Mostly it just stops some of the slosh and would keep it from dying going over a speed bump (which mine actually did). I returned the AFB clone and got a Edel Q-Jet. BEST CARB I EVER RAN!

I third the Edelbrock QJET. I had the Performer and it was a great street carb, but suckon the trail, even slow crawling would get it to hiccup if going on any inclines. The QJET on the other hand is a good running carb for me so far. Idles nice & low, and hasn't given me a problem on any incline I have given it. Idles where the performer wouldn't run when on the throttle. ;)

Another vote for EDEL q-jet. The q-jet on my blazer will idle normal and start first crank at 75-80*. Maybe more, but I havent got the truck up on end yet.

Charlo

Anyone run the Holley Truck Avenger? I have found a few places where I can get them for about $350. Just wondering if its worth it or not?

I don't really have the $$ for an Edelbrock Q-Jet, so i was wondering if the Rochester Q-Jets are half as nice in off-camber situations. My Edelbrock Performer sucks ass.

anybody out there know how much propane is used compared to gas and how is the performance if you add some compression

anybody out there know how much propane is used compared to gas and how is the performance if you add some compression

I only go through about 10 gallons in two days of wheeling. I'm only running about 10:1 compression, and have NO complaints when it comes to power. with the high octane of propane you can also advance the spark quite a bit.

Our whole crew is running propane and we have put together a complete parts list if anyone is interested...
http://austink5.net/phpBB/viewtopic.php?t=712

I only go through about 10 gallons in two days of wheeling. I'm only running about 10:1 compression, and have NO complaints when it comes to power. with the high octane of propane you can also advance the spark quite a bit.

Our whole crew is running propane and we have put together a complete parts list if anyone is interested...
http://austink5.net/phpBB/viewtopic.php?t=712

that austink5 post is awesome. VERY GOOD, definetly worth a bump. That helped itemize everything I need for a propane newbie! :cool2:

I'm running a supercharged 496 w/ Holley 850 Blower Carb, and to keep it from vaporlocking I used a Carter high pressure fuel pump and a Mallory bypass style regulator with return line. The regulator must be mounted on the firewall off to the passenger side to avoid getting it and its fittings hot. Lots of torque...

I have a 90 454 that I installed the Edelbrock TBI to MPFI kit which replaced the intake manifold and modified the TBI throttle body for air only. This combined with good exhaust and intake bits, makes more than enough power for pushing around my big truck. No, it is obviously not as powerful as a built big block with a holley or some other EFI conversion, but it works very well and does not have any of the issues that Carb's have.

The installation is easy, the vacuum hoses are pretty straight forward and the existing sensors are used.

Anyhow, besides a faulty distributer power module that is now replaced, I have determined the problem I have just recently had to fuel pressure.

The system requires a static fuel pressure of around 40-45 psi. The replaced pump in the gas tank was pumping around this PSI. As of now, I am reading static fuel pressure to be 0 and with the engine idling around 15-20psi. As soon as I turn the engine off the pressure drops to 0.

I have checked for fuel leaks, replaced my fuel filter (that did have crap in it BTW) and checked the hoses to the fuel pressure regulator. Fuel pump has power and you can hear it pumping. Everything looks good and all the hoses are very new (vacuum and fuel lines).

Just to be clear, everything was working great for several weeks of driving and then the problems started. I did have the gas tank down low twice, which leads me to believe that my pump filter might be partially plugged. That said, would not the fuel pressure slowly increase? Or is the pump "seeing" the pressure being plenty high because of the theoretical blockage? I am 99% positive that the pump is getting the proper amount of electricity. Should I be considering some alternative issues like "check the interal hose" etc?

- Note: I did not see any other thread in searching that was more appropriate, nor did I want to start a new thread just for my problem.

---------------------------

Problem with fuel pressure aside, the Edelbrock setup is easy to install, provides a bit more power (and in theory economy) and gives you all the advatages of a an EFI setup offroad wise. I can get up to speed in a hurry on the street and it does not matter what angle offroad I am at. :grinpimp:

On a side note,

A buddy has his K5 with the Holley ProFlow setup, blueprint engine, etc. and that has worked out very well. Naturally gas mileage is not so hot, but his truck is pretty quick.

470cfm Holley Truck Avenger on a wornout 305. Definately not as good as EFI, but better than the Edelbrock 600 or the rebuilt Quadrajet I used to run. Not an out of the box carb, though. Plan on playing with floats, mixture, secondary springs, and jets.

Been running the same Holley Projection-4 900 cfm unit for 16 years on 496 & 502 BBC's. Big Fram filters from NAPA mounted between tanks and holley pumps, -8 supplys, -6 returns. Dual Tanks ( 36 gal & 14 gal below the bed) with efi tank switch valve. Isolated Fuel Pressure gage mounted in cab with regulator set at 16psi. Only maintenance was replaced the TPS a couple times. MSD 6AL ignition & distributor. Engine will run on its side.

http://austink5.net/phpBB/viewtopic.php?t=712

This link's broken, and propane guy (Roy) (http://www.propaneguy.com/) has shut down his business. Anyone know of a good propane tech site? Preferably one with good turbo / propane tech?

I run a 383 stroker motor custom built 9.3 to 1 compression on 93 octane pump gas. Estimated 400+hp. My blazer had TBI fuel injection when I got it with a 305 motor but it would not supply enough fuel to get the true power out of a 383 motor.

The 383 has vortec heads and I converted the Throttle bottle injection (TBI) to multiport fuel injection (MPI) by edelbrock and use a holley 670 CFM air intake to supply air. Howell EFI provided the parts and a new chip for my stock computer. The system cost about $1500.00. 383 Stroker motor - cost $5000. Howell has been a great company to work with. They are GMC/CHEVY experts and they have many options and more knowledge than any one else I have spoken to.

The truck performs amazingly and I can go to the gas station fill up and go. Overall system cost was more than I wanted to spend. The motor was designed to provide maximum torque and hp on pump gas only. I have heard that the system can be converted to run E85 which would provide additional HP possibly 525 hp + due to the higher compression you can run. My intinial cost was high but I bought forged parts. After a 2 full days of abuse in mud and RPMs up to 6500 with no problems I am happy and I feel the money was well spent. The system performs well. I have not had any major issues yet. I had a excellent machine shop build the motor. If anyone would like further specs on the motor send me a PM.