So I purchased an 81 F100 with the idea of dropping in a 351W and making it a fun street/ weekend strip truck. Since this is coming to fruition, with my short block on the way in just a week or two, other things must be done.
Suspension/steering is my first concern. I don't necessarily want it very low to the ground, but it needs leveling. This thing corners like a bowl of jell-o. I have a friend that builds second gen lightings, and is giving me some advice, but I wanted to know what the forum had to offer in the way of ideas.
Initial plan was to replace the rear shackles (I can fab up some different style mounts for the leaf shackles) and fab long bars for the back, but I have no idea in which long bar kit to make work
The front end is by far my biggest hurdle. What to do with the radius arms? Chop springs and stiffer shocks enough? Fab lower spring mounts and run springs from something else?
Has anyone done something similar with these style trucks? Any tips?
Pictures of the truck to follow, and after a short stint in Chi-town some pictures of the short block as well!

Also, I am going to order a tank/sending unit/straps tomorrow, and am wondering if the sending unit with the return line for electrical fuel pump would be ok to run on the mechanical 300. I want to do this incase I want to switch to electrical with the v8. Is the plug for the sending unit the same? Will it still indicate on my dash the same? I can just block off the return line.
Sorry some of these might sound like dumb questions. I have never done much in the way of older trucks.

Thanks, Paul

 

You probably don't want to use the sender + pump combo unless you change your tank to one with a larger opening (which the later ones had).

The electrical plugs aren't the same, either, although it shouldn't be hard to figure out. One wire goes to the sender rheostat, one to the pump, and one to ground. Fourth is unused. Your dash gauge should be fine.

I don't know anything about lifting & lowering, hope somebody else chimes in.

 

I don't plan on using an electric fuel pump right now, and may not use one when the motor gets here, but I would like to avoid having to drop the tank to put a new one in later. What I would like to do is put in the sending unit with return line and run the return line down from the top of the tank and plug the line, so that if I run an electric pump I can just install and go. For the time being just run the single line to the mechanical pump.
Will the later tanks work on the 81 step side? The sending unit with a return line is bigger than the sending unit with a single line? If so, that's a bummer. I can fix the plug issue, I was just curious on that.

Has anyone out there tried to stiffen the suspension on the 80s trucks?

 

I have got zero personal experience with the "stepside" (a GM trademark) variant of these trucks, but later tanks should physically fit just fine if my experience with the other Ford trucks is an indicator.

The hole in the tanks for the non-EFI trucks is 2" and around 3.5" with in-tank pumps and EFI, the sending units match to accommodate. And, the electrical connectors are entirely different (already mentioned).

Other guys here have done suspension work, perhaps they'll stop by. Might also post in the Offroad/4X4 forum, also the Suspension forum. Maybe even in 87-96 since everything is very similar.

 

I know what NumberDummy says about LMC but they offer a 3.5" sending unit for a mechanical pump (i.e. one tube with 2 electrical posts). Not sure if this is the route the OP is going for but I am planning on ordering one this weekend.

 

I apologize on my nomenclature, is the ford flare side what I would call it? To think I have been wrong all these years!
Apear to most definately be the same tank, different size holes (via rock auto) thank you for the heads up.
Will try the other sites tonight, but would it be possible it to go up to the EFI sending unit (to have the return line run if I plan on upgrading to electrical fuel pump) or is that more of a hassle than it's worth?

That would be my route if I cannot put the EFI sending unit in with the mechanical pump, because I might as well put in the 3.5" tank so I can upgrade down the road. If I do run electrical pump it will be an in line pump, not in the tank, so if it is impossible to run the EFI sending unit without the pump on it, I will just have to run my own return line down the road.

 

I don't see why not, and you seem to have a handle on all the issues involved. The Ford sending unit for the 3.5" hole is combined with an in-tank pump, and lavatan says LMC has one that would fit that hole but that doesn't have that pump and has the electrical connections to accommodate the non-EFI style. I guess it'd be doable but would require the tank with the 3.5" hole as well as the sending unit, you're putting a fair amount of time & money into something you "might use in the future if you decide to go use an electric pump." I would probably leave well enough alone right now, and add it to the list of things that need to be done if you want to do an electric pump in the future.

Make sure your replacement 351 Wheezer has the necessary stuff to run a mechanical pump - the cam eccentric and the holes in the side of the block/timing case cover/whatever. You should also be aware that the EFI-style Wheezers (with electric pumps) generally also came with Serpentine belt systems which use water pumps & fans that spin the opposite way as their V-belt counterparts. Just something to be aware of, more than one person has shown up here with overheating problems because their fan & water pump are spinning the wrong way.

Styleside is the "regular" bed style, Flareside is the "stepside" variant.

IMO "Stepside" is a great name and kudos go to whoever thought it up. I personally can never remember which is which (in Ford's names) and have to look it up.

 

For shame, Chris.

I guess I'm confused. I just want to be sure I'm following the thread correctly:

1) The tank you have now has the 2" orifice

2) You have a mechanical pump but want to go to an electric pump down the road (why?)

If that covers it I have some suggestions. I prefer the mechanical pumps. Not as much to go wrong and easier to troubleshoot and the one's made for the 351's pump enough to make sure your not running lean whereas the one for the 300 may not pump enough. I'm not sure what the PSI or GPM is on those electric pumps.

That is just my .02 and you can do whatever you want obviously. As long as it runs the way you want is the only thing that is important.

 

I would definately leave the tank alone, but the tank is in rough shape, and it leaks around the sending unit. The straps are rusted to the tank, and look awful to get out, so I am replacing the lot regardless of using 2" or 3.5", just trying to set myself up for the easiest installation possible down the road.
I have a 351 Man o'War block stroked out to a 408 on it's way from Chicago, and it's getting a top down build, so it's up to me on how I want to build it from there. Mechanical fuel pump seems to be the way I want to go with the motor, but I've only ever really build 302 and 350 EFI motors, so electrical fuel system is what I know. Honestly thats the only real reason why I am going this route. The price between the tank/sending unit in the 2 or 3.5 inch route is about a wash, so I wanted to know what others might think about setting myself up for a possible electric fuel pump system.
I guess its not really an upgrade, but if the price and work is roughly the same, I might as well go for it.

1) Yes (it leaks, is very rusty, and the float is stuck/bad as I do not get a stable gas level reading)
2) Yes, I am dropping the 300 for a Windsor build and given that I have to replace the components anyways, why not set myself up for that as a possibility. I have installed many electric fuel pump systems, and this is what I was comfortable with.

Just understanding slightly less about mechanical pumps (although quite simple) I was trying to set myself up for a possible change down the road.
I guess the way I wrote it initially made the idea seem kind of fruitless, but this is why I posted!

 

So, tanks in and sending unit is in. But there is an issue.
So the non efi sending units ran 30 ohms to 10 ohms (10 being full) and the efi units run 10 to 160 ohms (160 being full). Now I have no gas guage! Bummer.
Anyone have any ideas on how to get it back? Junk yard a 87 gauge? Wire it differently?

 

haha! (just kidding)

 

So you got the EFI tank? Hmmm.

Get a fuel gage out of the cluster from an EFI truck?

 

Ah, yes, I remember this thread (now that I went and read the first post again).

Ya know, I don't remember seeing anywhere in the previous conversations about your possibly using a gauge from a 1987+ truck. If you had mentioned that, this could have been avoided.

Get the correct sending unit.

It's not just the gas gauge that changed, it's a fundamental change to all the gauges and how they work.

 

To be more clear, it was around 1990 when the fundamental changes occurred - they did away with the ICVR and used a different electrical configuration for the gauge cluster.

But, the reversal of the resistance came in 1987 IIRC.

Go look on parts store web sites, I think Rock Auto's site tells you the ohm readings of the different sending units.

 

Yes, I understand that now, the sending unit's resistance is set up for a different style fuel gauge. I get that.
I stated multiple times in previous posts that I wanted to switch to the efi style tank/sending unit (this would be the 3.5" mentioned above). Reason behind this was two fold. The orriginal tank was leaking quite badly and very corroded around the lip, the sending unit did not work at all, and the straps were barely holding on.
Second reason was that in the future I would like to be able to go to an electric fuel pump requiring a return line.

Considering the comment about the plug I thought it was understood that I was going to place a newer Efi style sending unit in place of the old one.