I recently bought a parts truck. Its a 78 F-250 4x4 SC with a 400. The original owner ran it with propane for many years. The guy I bought it from had taken the propane stuff off and used the truck for several years as a welding rig. The guy I bought the truck from still has the propane setup since he didnt include it with the sale. The 400 has been recently "overhauled". The guy I bought it from said he cleaned up the motor, put new rings and bearings in and basically freshened up a 130k mile motor. When I drove home it had good oil pressure for a 400. Any way my question is, would it be worth my time to get the propane setup from the guy since Im sure it would be fairly cheap. Ive never driven anything besides a forklift with propane so I dont really know squat about it in a V8. Is the power simular to gas? Is it more cost effective to run propane? Im going to put the 400 in another truck and while its out should I make any upgrades to help run on propane? Or do I scrap the whole propane idea?
Any suggestion would be appreciated.

 

If you have good compression and no or minimal oil loss go for it.
You will need to decide if the cost per gallon and availibility are worth it to you.
If you are planning on any up grades I would suggest at least doing the heads.
If this will be a bi-fuel rig I would also recommend a "Dual Curve" by MSD (You can get it through your lp supplier) It will allow you to run two timing curves an advanced one for LP and the std curve for gas

Regards

 

It would definitely be a bi-fuel setup if not a tri-fuel setup. Since LP likes higher compression and more advance timing a guy could use that to an advantage to also run E85...hmmmm.....
Dual Curve by MSD? Is that a distributor or an ignition box? What kind of head work do you suggest? Just your basic porting?

 

Dual curve is an add on box which allows you to advance the distibutor base timing when on lp then it limits it on the top. When you switch back to gasoline it "retards" the advance that you dialed in back to gas std timing. I would do a general port/polish
I use to recomend stellite seats and sodium filled exh valves but with an unleaded motor your half way there. Just remember LP is approx 125 octane it needs a hi intial advance then be limited to 32 or so on the top. Of course that assuming stock cams etc. If you have the facilties and the time you can play uite a bit but it may not run on gasoline hence the dual curve.

 

I can get that propane setup for $50 I dont know what all is included with it but it sounds like a good deal to me. I will let you know what I get later. And I found out more info on the motor. Sounds like it was a basic overhaul. I think I will bump up the compression and add a new cam. Other than that it seems to be in good shape.

 

Now dont quote me on this, but a dual system loses at least 25%, since it has to try and run effectively on both petrol and gas. Ive had mine converted to dedicated gas and you can tune your engine to within 5% of that of a petrol setup....but definately have a look at the heads. being a colder burning fuel, you'll find that it will run a lot better in summer, providing that your converter get enough water.

 

You will get lower MPG's and less power on propane. My experience has been that bi-fuel set ups don't work long term unless they come that way from the factory. If you can buy propane at the right price, and availability is not an issue, then there's nothing wrong with running propane. I've seen 300,000 miles out of a converted propane engine befoe.