Hey everyone, a guy from work lucked up and found a mint 94 F-150 truck for 400.00 with a 302 but the oil pump took a dump. Owner said it never knocked or seized but I told the guy it might have took a rod or main bearing if it lost oil pressure.

Anyway the engine has been sitting in front of the truck in the yard for 5 years with the pan off it under a tarp. He asked what I thought it would take to fix the 302 and I said "what about your 94 250 with the 351?" We knew it ran good and its been idle for 2 years since the transmission acted up and fuel pump went out. He said MPG was scaring him and the swap, which wouldn't be nothing since the 150 is mass air.

I asked what he was going to do with it and he said daily driver, I told him I would pull the bottom end down and check the rods and mains for wear cause the only thing that would cause low oil pressure that I could think of was bad relief in the pump or wore bearings. That would be piece of mind if I was going to daily drive it. While it was out and the bottom end was out go ahead and pull the heads and check the cylinders, which considering the pan being off and the position of the pistons in the cylinder could have rust in the cylinder, have to hone, and new rings.

I just see alot of unknowns to give an answer about the engine. The 351 was looking good but the mpg's was a concern. I told him he could tweak it a little and probably get the same or slightly better MPG's because the 351 won't need as much skinny pedal to get going and maintain speed.

Here is what I suggested

Pull the injectors and send them to be cleaned and tested

Either pull a set of GT40 head and send them to be checked and worked or order a set from a parts site, I found a set for 668.16 with shipping to the door. He could even do some clean up work in the ports for free. You can buy a single aftermarket head for that assembled

Put a small cam like a comp 35-349-8
OR
a set of 1.7 roller rockers with stock cam, bout the same price

Advance the timing to 14* with new plugs, wires, oil, and filters (basic tune up

A pair of cheap long tubes with a 3" Y (2.5 mandrel bend) to a hi flo cat to a SI/DO 2.5 chambered muffler

Leave the stock wheels and tires

I figured with this and sensible driving habits, he should be able to maintain 16-18 mpg.

Nice strong engine for about 1500.00 plus 400.00 for the truck. 1,900.00 for a sweet looking truck paid for, cheap tag and insurance, and has the bite to go with the bark (but that not were here for is it, haha) sounds good to me. Were just trying to figure what way to go, either 351 or rebuild the 302, I figure get more motor for about the same price but ya'll are the experts, I personally would just tear the 351 completely down, mic everything and build it back up with the above mods and call it a day, the 302 is fine for the Mustangs, but just like the 351 in a truck, tell me and I'll tell him.

Oh, forgot to mention I didn't think to check the gears, might could do a gear swap as well which would only cost the price of the gears, got the tools to swap them.

Thanks everyone

 

I have had both of those motors in my F150(with a cam and longtubes) and they both got nearly the same gas milage.. about 13city and 17-18mpg strictly highway. The 5.8 was 3 seconds faster 0-60 and a ton more fun to drive so it's a no brainer IMO.

 

Thanks for the reply Conanski, is there a big difference to be had with long tubes vs. shorties? I know the Y pipe is a choke point on these rigs so a new one is gonna get fabbed up so hook up won't be an issue, but as far and fit, finish and function, does one really take the cake? One other question, is it worth the money for an aftermarket intake or will the stock be okay? Not really looking for power, just better mileage. But I guess power and mileage go hand and hand. It will be hwy miles 95% of the time though.

 

Longtubes produce the most low rpm torque and that is what produces the best fuel milage, and since you are changing the Y-pipe anyway there's no reason not to use longtubes. I'd suggest Pacesetter headers with a custom 2.5" Y pipe into a 2.5" single exhaust system.

The stock 5.0 truck intake is very good and while the 5.8 version isn't quite as good for fuel milage purposes it's not worth changing it IMO.

 

Thanks man, he is starting to come around to the idea of the 5.8 swap. He just can't get his head around the idea of the 5.8 getting the same or better gas mileage than the 302, I know it won't get the mpgs of a newer truck but then again most aren't getting much better than 16 city when you get down to it. I haven't drove a 302 truck but remember the GM 305 and the 350 and the 350 just did better in a truck. We'll probably pull the engine this weekend.

So

Longtubes
Comp XE264-14 or 12 for a little bump, but probably 14
GT40 Heads
Injectors cleaned and flow tested
Good tune up
New 2.5 Y and Chambered muffler

I'll be sure to post back with mileage when it's up and running. Thanks .

 

The Comp 35-512-8 is better suited to your goals and the SD EFI system, Crane also made a "Truck Power" 2020 grind #444211.. don't know what luck you will have finding a copy. Both of these have a bit less 0.050" duration which will help build low rpm torque.

P.S. The cam I had in my 5.8 that got the milage I quoted above and also produced outstanding low rpm torque was the Crane 444232(flat tappet), compare the specs to the 444211.

 

It will be a MAF once in the F-150, but I see what you mean. They all call for new springs but since new heads are going on with new springs should upgraded springs be used or will the original springs be good?

 

Original GT40 springs can't handle 0.500"+ lift and are weaker overall than what these cams need, so if you're doing new springs anyway you may as well upgrade them.

 

How timely of a thread...

What gearing were you using Conaski? I've got an F250 I'm thinking of building a 351w for and was going to use an E4OD. It's got 4.10's now and 33's. I'm wondering if it makes any sense to go to 3.55's. I do a lot of highway driving. I also plan on using it as a work truck, so it'll be heavy... I'm thinking 7k lbs normally loaded.

Induction is still in the air. It's an 86 and I may stick with a carb or, I may swap to EFI. If I stay with a carb I'll use the US Shift controller.

 

My truck has 3.55 gears with 30-31" tires, IMO going to that ratio would be a mistake for you.

 

4.10's will be a mistake? Even with 33's?

That's what's in the truck, so to change that I've got to swap gears. I'm wondering if it's worth the fuel savings, but I will be doing a lot of highway driving at 60-65mph.

With 33's on it, would 3.73's or 3.55's be better?

And yes, I know 33's aren't the best, but the truck has a lift that I'd have to remove or 31's will look stupid. 33's are borderline.

 

No 3.55 would be a mistake, your truck will not get better gas milage with higher(lower numerically) gearing.

 

Ok, that's kind of what I was thinking, that it wouldn't be worth it to change. There's only so much economy I'm going to squeeze out of a big old truck and the benefit of easier starting will offset the higher rpm.

 

Well guess every dog has his day. The guy that was going to buy the truck offered it to me if I wanted it. He said he just didn't want to fool with pulling and swapping and still not have a running truck or just run into unforseen problems so I'll be picking the truck up sometime this week hopefully. I just hope the transmission is up to par, that's really the only thing that scares me. I'm pretty sure it has an E40D transmission but it's been sitting outside the truck for about 5 years so who knows. I do know that around here your looking at 1,800 for a rebuild, 2,600 for a reman from the dealer or 1,200 for an internet special.

I'm not really worried with swapping the engine or modding it, it will probably get better gas mileage with the MAF vs. SD in stock trim. I'm gonna install a mechanical oil pressure gauge and crank it. I'll compare cold vs. hot readings, then compression test, then a leak down once I get it out of the truck. Probably pull the heads and intake, the oil pan and pop some new seal in the front and read. Check for sludge and clean the pan and lifter valley and just see how bad the bores are. Then new gaskets so there aren't any leaks. Replace the all the old vacuum lines and just clean it up a little bit. Might even put a fresh coat of paint on the engine.

The only problem I haven't figured out is the 5.8 has dual intake hoses from the throttle body to the breather box and the 5.0 is a single with the mass sensor. How do most folk go about getting the 5.8 to work with the mass sensor? Do they just swap 5.0 upper or install a cold air intake for the 5.8 with the mass sensor inline?

I'm kinda of glad he changed his mind, I was in the process of building a I6 Ranger but I can get this truck up and running pretty quickly, alot faster than the other truck so maybe the force is strong with me ha ha! But I feel pretty lucky I got this truck.

And CONANSKI, thanks for the info and the help. I always look for you to chime in with your wisdom when it comes to these SBF. I'll be sure to post a pic of the truck when I get it home.

 

I was mistaken, the truck has a 4r70w transmission. Hopefully these are pretty good transmissions, don't know anything about these.