I am looking for input on some good performance increases for a EFI 5.8. This is a 1993 E350 4x4 van which I currently have the body removed from. I'll be installing the body from my 1994 E150, though I figured that this would be an excellent time to make a few performance improvements to the existing engine. It is a non-roller with about 75k original miles. After I swap the bodies, I'll keep the roller 5.8 from my E150 with the plan of building that into a higher power engine, but that will be a longer-term project (next several years). I would like to make some sensible modifications to the factory E350 engine to keep me happy for the time being.

Any recommendations on a good performance flat-tappet cam, or should I determine what exactly I'll do with the heads before making a choice on a cam? As far as heads, I am not really sure what to do. I am not looking to spend a ton of money, though I would like to gain some usable torque. Look for a set of used gt40 heads?

Should I consider any changes to the stock intake? I have almost no room above the stock intake, so I need to keep the same dimensions which may limit any aftermarket choices. I can do any match porting, but would extrude-honing be worth the time and money, or is there even any need to mess with the intake?

I plan to replace the entire exhaust system, though much of it will likely need to be custom made. The EGR adds quite a bit of mess and complication to the existing system, so I am considering deleting it. I understand what is needed to remove this, but will this cause any other performance issues?

Anything else that I should consider or be aware of?


Here is a view of the exhaust mess:




Engine work on this van will never be any easier than it is now


Thanks!
Dave

 

A cam, and exhaust is about all you can safely do with the 5.8 and the stock EFI setup.. that will push the injectors for all they're worth and really wake it up. The Crane 444232 works awesome with this motor but it may be hard to get now that Crane is temporarally out of business.. Summit still has it listed though. There are other cams with similar specs you could use but be sure it has at least 114 deg LSA to keep the computer happy. The only intake made specifically for a truck motor is the Edelbrock truck Performer but it's a lot taller than the stock intakes so it probably won't fit in a van. You could use the regular Performer but changing the heads and intake will put engine breathing capacity well beyond what the computer can handle anyway so I don't recommend it. The mess of plumbing on top of the engine is not the EGR it's the Thermactor(air injection) system. If you trace it all you'll see the valves on top are connected to the tube connecting the heads at the back of the motor and the air pump. All this can be deleted, plug the holes in the heads with 5/8 x 1" coarse bolts with copper washers, remove or gut the air pump, and remove the vacuum lines between the TAB and TAD solenoids and the diverter valves around the motor. But leave the solenoids on the motor and electrically connected to prevent codes, they are located over by the coil...

 

Also, now might be the time to work on any extra ports for remote coolers or remote oil filters for the engine, transmission, coolant, or bigger oil pans. Also wiring for sensors for temperature, pressure,... and other gauges. Just an idea.

 

Awesome, thanks for the info Conanski! So if I follow the proper proceedures, I can delete both the air injection system and the egr without causing any problems, including upsetting the PCM? That would certainly clean things up and make getting a new exhaust system much easier. If I am sticking with the stock heads for now, would shorty headers be adequate? I have no idea if I would have the room to
route some long-tube headers.

Just out of curiosity (and for the future build), what would need to be changed about the EFI to accommodate additional modifications? Computer and components from a different vehicle, or a stand-alone system?

Good idea f250ssd, now would be the time to upgrade the transmission cooler (with a fan) and add some additional gauges.

Thanks!
Dave

 

Deleting the air injection is no problem but removing the EGR may set codes and it' won't really gain you any performance or clean up the engine bay so you may as well leave it.
Shorty headers are certainly better than the stock manifolds, but upgrade the Y pipe too for best performance gains.
You will need a mass air conversion for aditional performance, a mass air truck computer and meter along with the engine wiring harness could be salvaged from a junkyard vehicle, there were more of these on pickups towards the mid '90's but the system started appearing as early as '92.

 

Ok, now I see what you were talking about. I was still thinking that the tubing was EGR related, but it is in fact part of the air injection system. Good to know. I placed an order for the cam, so we'll see what happens. I'll put the MAF conversion parts on my list for engine #2.

Thanks!
Dave

 

Well the cam showed up today, so Summit must actually stocks this part. Now my next dilemma is how to proceed with the headers. Do I go with some long tube out-of-the-box ones? I assume an F350 4wd would be the closest match, though that may not mean much. I guess if I purchase from a place that allows returns, it would be worth trying. I did find a manufacturer that makes custom headers which is a couple of hours away, though having the chassis towed there just for headers seems like a hassle.

Will I regret not doing more to the motor while I have it at this point? Probably. Any idea how much difference the cam + long tube headers + full exhaust will make over the stock setup? MAF system conversion, injectors and head work (or new heads) would be the next logical performance step? Would anything else be needed?

Thanks!
Dave

 

Pickups with a solid front axle have clearance problems around the front driveshaft and pumpkin with longtubes designed for a TTB pickup. If you can source a set for an earlier truck with a solid axle then you may have better luck but there's still no guarantee, but if you have access to somebody that's decent with a wire feed welder problems can be solved.

The cam and exhaust will really wake this motor up, loads more TQ from idle up and it'll just keep pulling way past where the stock motor goes flat. This will stretch the stock injectors for all they're worth.. close to 300hp. Once you get better heads and intake on there bigger injectors are required and then you're not only into a MAF conversion but a tuner as well. I have been playing with 24lb injectors on my truck recently and even with a tuner making them cooperate isn't trivial, it's going to take a bunch of experimentation before I get it sorted out.

 

Ok, good to know. Any idea when Ford stopped using a solid front axle in the trucks? Well, I can search the forums for that info. I am decent with welding, so if I can find something close I think I could work with it.

I am looking for a relatively quick and easy engine build for this version, so I think I will stick with just the cam and exhaust. For the next engine build, I should probably find a beater vehicle to install and tune the engine in. Once the van body is on, almost any engine work becomes a major pain.

Thanks!
Dave

 

hah i picked up a set of flowtech longtube headers at a local swapmeet for $15... they are made for late 60's early 70's couguars and so on... they bolted right up to my 351w... i will be dropping the motor into my truck this weekend and i guess we'll see if there are any clearance issues... doesnt seem like there will be, but time will tell i guess

 

Yeah.. bolting headers to the motor is never a problem since all 351 windsors are exactly the same, it's around the driveshaft, frame, and firewall that you'll have clearance problems.

 

The engine is stripped down to the short block and unfortunately the combustion chambers look dirtier than I had hoped. At this point I am going to take the block and heads to a machine shop for inspection, cleaning and any necessary work. I might as well have them install the new cam while it is there.

 

That looks pretty good actually, there will be more carbon in the rear chambers due to the location of the PVC line so what you got there is pretty common, but there's no gunk inside the motor so it had regular oil changes at least and that means the crank should be fine.

 

Ok, good to know. There did not seem to be any sludge in the engine, though I was surprised at the amount of solid material at the tops of the cylinders and on the pistons. Part of me just wants to clean it up, swap the cam and put it back together, but I guess having everything checked would still be the sensible thing. It did just occur to me, however, that I don't actually have to put the van body back on to start and test the engine. As a matter of fact, it will be much easier to address any issues if it is just the chassis.

Here are a few more pictures of the guts:




Thanks!
Dave

 

That motor doesn't have a lot of miles on it, if the bottom end hasn't been stripped yet I'd suggest you don't and just clean up the combustion chambers and pistons with a wire wheel and put it back together.. unless your plan was to do a complete rebuild with new bearings and machine work anyway.