383 on PANE! bueler? bueler? advise on setups

Erik

Erik

Well-Known Member
Joined
Oct 20, 2005
Location
Wilmington, NC
THINKING about my v8 swap and tryign to decide if the LS1 is worth the coin.... the fuel injection and weight are two huge pro's, but the price is a weeee bit of a con...

a worthy alternative is an old school cast iron 350 on pane.... carbs and gas suck, i'll never run one for many obvious reasons... but a carb and pane? hummm... just as versatile as fuel injection, cheaper than an ls1, and since this is no longer my only mode of transportation the pane wouldn't be a problem.....

so... anyone running a sbc on pane? what does your setup consist of? would you do it differently if you did it all over again?

any reason a lil stroker 383 would create problems for me as opposed to a 350 when dealing with propane setups?
how hard is it to dial in your carb and mixer? do you find yourself ever having to adjust anything or do you set it and forget it?

thanks guys... just trying to get my head clear and weed out some of the bs i hear about running pane so i can decide whether or not my old school sbc on 'pane is a mistake waiting to happen.

planning on a 425, Model E and VF30... and a couple tanks of course.... just not sure what kind of carb and intake manifold

-Erik <--- selling his 4 link parts to fund his sbc swap! leafs 4 life!
 
if you can run a 350 on pane then youll have no problem running a 383 on it......im trying to find the link to the guy that was running carb and pane on a 400 small block, and just used the pane when he was offroad, and just the carb when he was on road, i know he would cut the elec. fuel pump off and run the carb out of gas so no worry of fuel running over offroad, and had some kind of idle circuit to run just pane, no gas, offroad.

ill try to find the link

IMHO, if you are going to spend the money for the small block, stroking it, good carb, pane setup, I would take that same money and go buy an LS- engine and just run the stock injection
 
If you try to run dual fuel, you're going to lose a LOT of power over a straight propane setup where you can optimize the compression (higher), cam, timing (advance in much sooner), and intake (single plane is just fine) so you don't lose power over a gas setup.

Erik, have you thought about a 5.3? They're going (on average) for about 1/2 a 5.7 LS1 and other than losing some torque right off the bottom, they'll likely make just as much power as the 383 on propane, and would CERTAINLY out-power a dual fuel setup.

Besides, propane is stinky..
 
not looking at dual fuel... straight pane all the time :)

i can build a stroker for pretty cheap since i can get a free rebuildable 350 from my buddy's pops... the only cost involved would be parts and some of the labor (his dad owns a machine shop and said he'd take care of me as best he could)... plus i wanna be different... a 350 swap is pretty common now-a-days... but pane isn't and i'm an attention whore :)

the reason i was having converns is b/c i see tons of folks saying that the impco 425 is only good for 300 hp... then i saw somewhere that it could handle up to 350... then i read that a guy had right at 400 hp and no problems.... i gues that's where my concern with a somewhat built 383 would be too much (as opposed to a relatively stock 350)
 
Erik take the engine out of the astro and put in it,same thing i got in my junk
 
i dont think the 425 would like a 383 esp in the higher RPM range... first thing i youll want to figure out what the needed CFM rating for your engine is...

CFM Required = CID x RPM / 1728 / 2 x VE

where:
CID is the cubic inch displacement of the engine
RPM is the maximum engine speed
VE is the volumetric efficiency (0.85 or 1.00)

The 425 flows 460 CFM which would probly be too low for that engine... you probly need around ~650-700 CFM for a decent 383...
http://cars.rasoenterprises.com/Propane-Impco.htm

but that being said, with the availabilities in the aftermarket you could run dual 425s and have enough flow... or try using a mixer from a different company...

I know Chris (792.5cj5) is running higher horsepower engine with pane, so maybe he can chime in on his setup...
 
but that being said... I might would look more into what Rich was saying, as the LSx series truck motors can be had for a decent price... and then you have all the FI and what not
 
I'm running 'pane on my CJ and 715. One good thing is that propane won't go bad sitting. I don't think gas hardly keeps for 2 months now. At most my CJ and 715 will get a couple thousand miles a year each...with no gaumed up carbs to deal with.

You make mention of a carb... You won't have a carb, as such...you'll have a mixer (the 425), a throttle plate, and possibly an adapter to match your manifold.

Someone above mentioned dual 425's -- worth considering...do the airflow calcs and see.

Read up at rasoenterprises.com... http://cars.rasoenterprises.com/
And the alternative fuels forums: http://fuelsforum.rasoenterprises.com/

One advantage of propane is that it's stupid-simple. Easy to rebuild the mixer, etc with cheap parts...field repairs are feasible. You can run your motor with one wire (hot to the HEI), no computer, etc to die at the worst time. No fuel pump, no injectors.
 
Both are good and could have pros and cons. To do the job cheap and easy, without much wiring, I hate wiring, Propane all the way. Since you can get a motor cheap/free and machine work cheap/free is a no brainer. Get the motor done up to 10.5 to 11 comp, use high quality pistions and rods, get your bearing coated, ss oversized valves, roller top end with high spring rate, go crazy on the heads--THAT IS WHERE THE POWER IS AT, use good head gaskets and maybe some ARP bolts/studs. For the intake use a torker, or one of you choice. MSD or some type of hot spark system, thick wires, and cooler plugs.

Now for the fuel. The impco 425 is a good choice. I would go with the OHG-450x, if you haven't already bought the impco. I use it and I'm very happy with it. It dosen't use a diapham, just o-rings. I also use 2 reg's. 1 on with the ing and another on with a switch when I need it. This adds more fuel to the fire when needed. It works, you can feel it, and I've never had a problem due to lack of fuel. I run a 408 dodge stroker that spins 50's for fun. Also I think it helps with fuel economy also. I think if I would have gone with 2 mixers I could suck down a tank at idle.

The only reason I would consider going the other route is if you plan on doing much road driving. Propane isn't that easy to find and mpg will kill ya on the road. But if you plan on putting it on a trailer then just add propane.

Hope I've helped and not just confused ya. Let me know if ya have any questions. Oh yeah, I forgot to say- propane is stupid simple to hook up and only 1 or 2 adjustments to make.

Chris
 
I run a stockish AMC 360 with the 425/Model E/ Vff30 set up. It's been on there something like 3 years. Only adjustment I have made was setting the timing in the beginning, and idling it down for a slow crawl competition.
I have had friends run built 350's. 400 sbc. 351w. The difference being the 400sbc is built, and runs lean when he really talks to it. The 351w got the best economy. The mild built 350, and my 360 did about the same.
The 425 will bolt directly to a Holley square bore base plate. If you use a spread bore intake you will need either an adapter to put the 425 to the Q-Jet base plate, or an adapter to go spread bore to square bore. ($20 bucks when I bought mine at Advance)
I am not real big on the skinny pedal so mine has worked fine for me. For me, it's all about gearing. As I see it, the more HP you have the more you will break, and the more heavy duty you have to build it to keep breaks down to a min.
If you plan on doing much road driving, I don't recommend propane. If it's mainly a trailer queen, go for it.
The main thing you want on the engine build is hardened seats in the heads, which it should have if it was built to run unleaded fuel. Also Stainless valves. Everything else will hold up fine.
Dual fuel as said will kill you power simply because Gas and LPG need two different timing set ups.
Check out 4X4girl on here. HE has complete set ups, tanks to mixer and everything in between to get you going.
 
so maybe a semi-built 383 on pane is a bad idea and i should just stick with a 350 w/11:1 or so compression, a nice cam, and some decent heads.... it'll be a huge improvement over my worn out 4.0 either way, and since i'm pushing the strength of my hp44 anyway the slightly less power could be a good thing :)

running dual 425's is feasible but my reasoning behind wanting to go with pane is to keep it SIMPLE and adding a second 425 seems somewhat counterproductive to that concept.

i do plan to drive this on the street.... probably 100 or so miles a week at most, weather and work schedule permitting.... the only problem i see going this route and being street driven will be my drives to and from uwharrie.... i'd run dual tanks no matter what, but if the fuel economy takes such a big hit that i can't drive to uwharrie on 2 tanks then i'm gonna be up the creek without a paddle....
 
Aslong as you run 2 tanks, I think you while be fine. For road driving I would use some type of y harness to link the tanks together or a guage to see how much is left. When you run out your out, not much warning. As for the 383 vs 350, I say go with the most power you can get and adjust your foot. But thats just me. That hp44 is going to scream ctm and cryo if ya beat on it much.
 
The Guages that some tanks have are semi-accurate if,...... you are on flat ground, and not moving. I have both of my tanks hooked up at once, but only run one at a time. This way, when one tank runs dry, I know I am for sure at ?half of a tank(capacity)
 
792.5cj5 said:
Aslong as you run 2 tanks, I think you while be fine. For road driving I would use some type of y harness to link the tanks together or a guage to see how much is left. When you run out your out, not much warning. As for the 383 vs 350, I say go with the most power you can get and adjust your foot. But thats just me. That hp44 is going to scream ctm and cryo if ya beat on it much.
Click to expand...

i'm looking more at the dual mixer setup, but i'd like to keep this as simple as possible....

as for the hp44, i've got chromo inners and outers and yukon superjoints for the time being.... when they start breaking i'll most likely replace what breaks (under warranty), rebuild the whole axle, and sell it in favor of a 60.... i am kinda partial to the hp44 for ground clearance but if it won't hold the power then it's no good to me so screw it....

upnover said:
The Guages that some tanks have are semi-accurate if,...... you are on flat ground, and not moving. I have both of my tanks hooked up at once, but only run one at a time. This way, when one tank runs dry, I know I am for sure at ?half of a tank(capacity)
Click to expand...

good idea.... i'll keep that in mind when i get this setup going.
 
well if you decide to go with a dual mixer setup instead of the bigger mixer and dual lockouts like Chris is, then id look at progressive throttle linkage, so that your not pouring too much fuel at idle... that way you only run off 1 mixer mostly until you need the other mixer to kick in.... the mixers actually use a carb baseplate so the linkage and what not are the same for the brand throttle plate you are using...
 
any links for the progressive linkage setup? i'd like to get a visual of what you're suggesting if possible.....
 
heres something for carbs, but works the same...

http://www.chevyhiperformance.com/howto/148_0403_dual/index.html

basically the likage is hooked together but your secondary throttle link isnt at the same angle as the primary, so when the throttle is engaged they open up at different ratios, therefore making it possible to run mainly off 1 carb at lower throttle times, but have both avail for wideopen throttle situations...
 
anyone ever set something like that up? looks like it would be hard to dial in....
 
there's very little adjustments on these.. and since they are air-demand-based, it's pretty hard to screw it up, too..
 
i was reading a forum today and was reading that the 425 would be plenty for a moderatly built sbc 400 or a healthy relatively stock big block? how could that be if it only flows 450 or so cfm?
 
That's mostly because most people don't drive around at WOT & at red line, and also because the air flow calculations used to size the mixer assume 100% pumping efficiency, which you're not gonna get.
 
ok that makes more sense. i've got a heavy foot so i guess my goal is to find out what the max i could do with a single 425
 
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