I'm hoping to pick a few brains here. I've been reading threads here and at FordSixPerformance about turbocharging the 300. It's really piqued my interest. I'm reading a couple of the books recommended on turbocharging, but I'm hoping for some real-world experience and anecdotes from you guys.

A little background:

I am planning on building a '74 F-250 dually into a workhorse. It will have a steel flatbed, my trip-hopper cattle feeder transverse mounted behind the cab, and a LOT of tool boxes. It would, on occasion, pull around 12-14k worth of trailer and equipment. My '79 F-150 currently hauls all my tools and I've had to put two sets of front springs in it in ten years because they keep snapping from the weight. I have a '76 CrewCab (460 power) to do my real heavy-hauling or longer trips with. My daily driver is expected to be a workshop on wheels here on the ranch.

I've got a no-miles 460 I could put in the '74, but I'm intrigued with the idea of getting high-teen mileage figures with a turbo 300 as opposed to about 10 mpg with a 460. I don't want to build a hot-rod or drag racer. Most of the time it will spend idling around at less than 35 mph. I want something with stump-pulling torque (chassis already has an NP435 in it) that will be able to pull a reasonable load a short distance (30-50 miles) at 55-65 miles per hour. I also want to fuel it with propane.

My goal here is to build this at a reasonably low cost with off-the-shelf components, or at least with the minimum amount of fab work. I don't want to have to put in special cams, pistons, or other internals. I'm shooting for this to be as simple, reliable, and economical as possible. To that end, I already have a 300 engine set up for propane. It is an industrial 300 and was used as the engine on an irrigation well on the ranch. It has a fair number of hours on it, but uses no oil. The head was pulled not long before we quit using it for pumping and there wasn't enough groove in the cylinders to suggest a rebuild was necessary. Since the head was off the valves and seats were ground and lapped, even though the mechanic said they didn't really need it.

Now, with that long preamble, has anybody here run such an engine on propane? What, if any, modifications will be necessary on the propane system? Give me some food for thought, guys. I want to hear your ideas.

 

Just did some searching--hard to find anything other than racing conversions with the turbo/propane combo, or just straight propane conversions.

IMO a 12 valve Cummins swap would be a better way to go for what you are going to do.

I do recall several magazine articles back in the '80s about adding a turbo to a gas motor. Part two of the article was usually about melted pistons...

 

Yeah, I thought about a Cummins, but I don't like the weight or the amount of modifications/fabbing I would have to do, or the expense of buying a diesel. If it comes to that, I'll just drop my 460 in.

I'm trying to mainly use what I have on hand. I'm considering propane because it's just over $2.00 a gallon around here right now and a friend of mine who owns a propane company has several different sized tanks I could pick from.

Thanks for the input, though. Ideas are what I'm after here.

 

If you can go straight propane without the turbo, you might be ahead. The sites I found talked about changing the ignition advance etc with propane to make a better runner out of it. That motor has really low compression, which is a negative, but you could probably get enough power out of it without the expense of the hairdryer job to make it worth while considering the low cost of propane.

 

Well, I ran across this researching propane/turbos tonight:

However, one great way to take advantage of the potential of propane is through turbocharging. The turbocharger overcomes the loss in volumetric efficiency and the higher octane rating of 104 allows higher boost pressures.

Apparently an old hotrodder by the name of Ak Miller had some success running propane with turbos.

I'm still digging....

 

I like you're idea man I've thought about doing it to my 300 that I had built to handle a turbo. I still may do it, but you have some disadvantages to gasoline.. For one the power potential is less due to the lower btu's, and there aren't too many people out there who can tune a propane running engine, let alone a turbocharged one.. The advantages, like you pointed out, I think do outweigh the disadvantages. Higher octane is a must when running boost and you get a cleaner running engine that will run longer and with less cost. I think you can do it, just keep us posted on how it goes. I'm still putting my 300 together so I might have some questions too.

 

Impco has all different size propane hats as well if you're looking for an induction system and you can find 4 barrel intakes on ebay for the 300, which I would deffinitely look into if you want more torque and will probably need to supply enough fuel. You can also get a little more lift out of your cam by installing the chevrolet 250 0r 292 inline rocker arms.. I think they're like 1.75 ratio compared to the factory 1.6 and they're cheap enough for an extra 25 or so horsepower

 

I'm still researching and being in the middle of rebuilding my Crew Cab, it will be a while before I can get started on this project. There's another guy who's ahead of me on turboing his 300. Here's his thread:

https://www.ford-trucks.com/forums/1...ged-4-9-a.html

 

I have the same project going. Have a 77 f150 2wd with a 4spd. Im going to switch to propane first get it driving then go to a turbo. With some searching on craigslist i found a Impco 425 mixer and a model L regulator for $150 then i also picked up a 28gal motor fuel tank from a van for another $150. It is the perfect size to mount in between the fuel rails under the bed where the factory on is. Also hase a gauge and a remote fill:-)

Have you decided to do blow through or draw through? I know Got Propane has gits for a 22r that does draw through. Im planning on running a inercooler so im doing blow through at maybe 7 psi max.

Only other thing i need is a Turbo, just got a lead on a t3/t4 super t70 turbo for $150. I think it should be the right size for this engine. The guy said he stated building boost at 4600 rpm on his 4 banger honda sooo i hope that means it will do that at 1500 rpm on a 300.

 

I'm sure you can find a compressor map for that turbo. You don't want to over speed it.

 

Back in the 70's I turbo'd a 300 in my F100 4 speed 4x4 shortbox. Literally woke the engine up at 5-6 pounds boost but broke head bolts pretty regularly and became too unreliable to continue the turbo usage. I admit my knowledge then and the available help from anyone was very much lacking. Would outpull my brother's 360 in an almost identical truck with ease. Once turbo boost came in felt more like a 390 4bbl under the hood.

 

You were breaking head bolts at 5 pounds? If that's the case, I'll want to change those before I drop the engine in the chassis. I've been told a stock 300 should be good to 10-12 pounds.