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Discussion Starter #1
Let's say you have a '93 351W out of a F250. But you have none of the wiring or control modules. But you do have a complete propane conversion setup. You also have a '69 Bronco that needs an engine. The Bronco is rough but complete and would make a great crawler. Would a person be making a huge mistake heading down the path of converting to propane?
 

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I think your first order of business is to decide if running that vehicle on a fuel you have to seek out beforehand and keep stock on your tow rig is the best use of that vehicle, some guys drive to the trail some guys trailer, some guys wheel for an evening, some guys make a week of it.
 

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That is a fair point. I do have 7 tanks and plan to trailer it, but where I live there are several gas stations that offer propane fill-up. I guess my question is more regarding how difficult it is to turn the EFI engine into basically a carbureted engine. I suspect it is not that hard and I'm making this more difficult than I should.
 

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That is a fair point. I do have 7 tanks and plan to trailer it, but where I live there are several gas stations that offer propane fill-up. I guess my question is more regarding how difficult it is to turn the EFI engine into basically a carbureted engine. I suspect it is not that hard and I'm making this more difficult than I should.
Basically you just need an intake manifold, the propane mixer, and since you don't have any of the wiring to go with it I'd just throw a one wire distributor at it. Either convert something from points to a pertronix ignition system, or one of those cheap GM style HEI distributors. Not sure how common they are for 351W but I'm sure there is something out there you could use. Also strip all the emissions crap (Air pump, EGR, etc off and plug off the holes in the exhaust manifolds where that comes off.)
 

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I bought one of the 1 wire hei distributors for a 400m off amazon, $55ish and a $8 plug, zero complaints for the 1k miles I drove it. At that price you could buy 2, test both, and keep in rig.
They have a ton of reviews, good and bad, but I expect 40% of Chinese electrical shit to be DOA and plan for it
 

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I dunno about your area, but propane seems to be $0.50 higher than 87 anywhere I can find it. More money for less BTUs doesn't sound cool to me at all.

You could easily obtain everything you need to get that engine running in the scrap yard for cheap. My vote is to go that route and run a readily available fuel you can buy or borrow from anyone.

One of the 400 hp fuel only Fitechs or Sniper EFI, used carb manifold like a Performer, and a carb style distributor would be higher on my list than a propane conversion. If you don't care for the 1 wire GM china dizzys, you can just run a 4 pin HEI module, stock duraspark (last forever) and any old HEI or TFI coil.
 

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Discussion Starter #8
A person would make a huge mistake wasting time to transplant a non-roller 200HP 351 boat anchor.


This is I really good question. I don't have any money in it is the only good answer I have. Could it not be made better with a few upgrades and by removing the smog stuff?
 

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Basically you just need an intake manifold, the propane mixer, and since you don't have any of the wiring to go with it I'd just throw a one wire distributor at it. Either convert something from points to a pertronix ignition system, or one of those cheap GM style HEI distributors. Not sure how common they are for 351W but I'm sure there is something out there you could use. Also strip all the emissions crap (Air pump, EGR, etc off and plug off the holes in the exhaust manifolds where that comes off.)
^This is exactly what I did on my YJ; Performer RPM intake, GotPropane system, points style dizzy with a Petronix drop in kit, and boogie! I have zero complaints about the setup other than the unsuspecting no-go when the tank runs dry, and the inability to splash a jerry can into it to continue along.
 

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DUMB. Do not convert to propane from EFI.

There are plenty of write ups on how to use Mustang EFI on a 351W EFI engine. In fact I wrote one of them on this site. It's been running strong for over 10 years as a matter of fact.
 

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Yes, easily. It's also easy to swap to a roller cam.
Yep. Unfortunately OP, you're 1 year away from having a factory roller block, but there's two options if you wanted to do this. Cheaper: use stock lifters, a dog bone and spider kit, or more expensive but popular with the race crowd: Link bar lifters and a reduced base circle cam. Problem is the height of the lifters.

For a Bronco, I'd honestly be happy with a nice flat tappet to match whatever heads you might end up with down the line.

351 blocks can handle a lot, despite everybody saying they're the same as a roller 302 and split down the middle at 450 hp. It's just not true.


It's not a stupid heavy vehicle though, and depending on your style of wheeling it may not even be necessary to change heads or bother with a roller cam. You might be fine down the road with just an aftermarket cam and maybe some home porting if you're willing.
 

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Discussion Starter #13
DUMB. Do not convert to propane from EFI.

There are plenty of write ups on how to use Mustang EFI on a 351W EFI engine. In fact I wrote one of them on this site. It's been running strong for over 10 years as a matter of fact.
Perception is reality.

I have all the propane conversion stuff and none of the EFI stuff. I'm trying to do this on the cheap and investing 500 to 1000 or more on the stuff I need to do the EFI to me is dumb.



Anyway, this is all great info and i appreciate everyone's input.
 

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Perception is reality.

I have all the propane conversion stuff and none of the EFI stuff. I'm trying to do this on the cheap and investing 500 to 1000 or more on the stuff I need to do the EFI to me is dumb.



Anyway, this is all great info and i appreciate everyone's input.
Can you sell the propane kit to help fund the efi?


Propane is a lot cooler when it's not on a low compression truck engine. Bump her up to above 11:1 or a bit more and we're talking. If that fits into your plans down the road, I'd say it's a good choice if you want any power. But, if that's not a big deal, carry on.
 

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Discussion Starter #15
Can you sell the propane kit to help fund the efi?


Propane is a lot cooler when it's not on a low compression truck engine. Bump her up to above 11:1 or a bit more and we're talking. If that fits into your plans down the road, I'd say it's a good choice if you want any power. But, if that's not a big deal, carry on.

Currently I am running the LP setup on an 81 CJ7 with a 360 from a 77 Waggy. I think it's rated for about 143 hp. Seems to have enough power for crawling. I think 200 would be sweet. The reason I have this engine is that its attached to a transmission I bought.

The CJ is in decent shape and needs a back seat to accommodate the kids. So long propane. Might as well put it in a rough Bronco that would be a cool crawler, in my mind.

I'm going to run to propane on a basically stock engine, I think.
 

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at work we got in an EB with a 351w in it a while ago, engine bay looked pretty crowded, like almost 460/fox bad

sell it for a couple hundred and get you a 200 dollar 302 and fawk with that instead, shorter deck height will help with engine bay room

either way, duraspark dist is good shit, use a 4-pin GM module if you can't find a good OEM duraspark box
 

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Currently I am running the LP setup on an 81 CJ7 with a 360 from a 77 Waggy. I think it's rated for about 143 hp. Seems to have enough power for crawling. I think 200 would be sweet. The reason I have this engine is that its attached to a transmission I bought.

The CJ is in decent shape and needs a back seat to accommodate the kids. So long propane. Might as well put it in a rough Bronco that would be a cool crawler, in my mind.

I'm going to run to propane on a basically stock engine, I think.
Remember, you're going to have less than stock due to a lower energy fuel, but it should probably be better than a mid 70s 360. If you're going to be happy with the power it produces, go for it. If crawling is your primary thing you don't really need a lot of power. You can always save up and rebuild it into something better down the road if you want.
 
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