Top End Performance and Maintenance

[fords4life]

Motor has 160k original miles and is bone stock untouched. It also needs new valve cover gaskets and has an oil leak at the rear of the lower intake manifold. Going to be R&Ring the lower manifold and valve covers in the next couple weeks. I'm new to the older motors and am not familiar with all the little tricks. Anything I should make sure to check out or any performance upgrades I can do while I'm in that deep? No head swaps at this point. Some porting working on the manifold would be easy for me. Also plan to check compression and put some new plugs in it.

[Gary Lewis]

I've read that port-matching the intake to the head is good.  But there's not much else to do.  And, with a speed-density system you really can't change much even when you do pull the heads.

And the front and rear seals are a pain.  I like to use RTV for them and not the included gaskets.  Put a 1/4" bead of RTV on the walls at each end, and using cut-off bolts for guide pins lower the bottom plenum on evenly.  Tighten down the proper bolts finger tight and let it sit over night for the RTV to cure.  Then come back and torque the bolts down to spec.

But the walls and the plenum have to be CLEAN or the RTV won't stick to them.  

[85lebaront2]

Unfortunately your engine has the absolute worst heads Ford ever used on a 302, or any Windsor engine. If you can find a set of 5.0L Explorer heads in a junkyard, there are two types, the first ones had GT40 heads, later have GT40P heads. The GT40P ones have a P stamped on the ends. They will work with your intake quite well.

[fords4life]

I'm assuming there is no way to step up to a slightly higher flowing injector on these motors?  

What about the E7TE heads?  I'm picking up a free pair that came off a running driving 351 this week.

As far as clean....I always use lacquer thinner on surfaces like that.

[Gary Lewis]

Type in D8OE vs E7TE on a Google search and you'll see a lot of opinions.  But the main difference in the heads is combustion chamber size.  The D8's have a 69cc chamber and the E7's have a 63cc chamber.  Working from memory, which is very dangerous in my case, that will take your compression ratio from about 8:1 to 9:1.  And that's a good thing.

So, if you have the E7's I'd put them on after having the valves an guides/seals done.  However, the GT40's and GT40P's are even better heads.  So before you sink the money in machine work on a pair of heads see what you can find.

Here is an article that may help: https://www.americanmuscle.com/cylinder-head-upgrades.html

[85lebaront2]

Higher flowing injectors are easy, 302-351 use 19#/hr injectors, stock 460 ones are 24#/hr. If you change injectors, the computer has to be programmed for the larger injectors otherwise it will be pig rich starting and running in open loop (under high throttle conditions).

[Gary Lewis]

Yep.  But larger injectors really aren't going to help a stock or even mild 302 since the 351W used the same injectors.

[fords4life]

Gary Lewis wrote

Yep.  But larger injectors really aren't going to help a stock or even mild
302 since the 351W used the same injectors.

I guess that was where my question was headed with the injectors....wasn't sure if there was enough air flow to be able to take advantage of a larger injector.  

As much of a headache as a carburated motor can be.  I'm also learning the restrictiveness in making "easy" power with the factory EFI setup.  Oh well, that's probably a good thing since this is supposed to be a driver.

[Gary Lewis]

Yours is fuel injection, but it is an early-style system.  It is called "speed density" because the computer only knows the throttle opening, air density, and air temp.  With that info and the computer's tables it assumes it knows how much air is entering the engine.  But, if you change things, like install a bigger cam, high-flow intake or exhaust, etc then the tables are no longer correct and the computer isn't happy.

In roughly 1996 the trucks got a mass air flow system, and with the MAF sensor the computer actually knows how much air the engine is ingesting, so you can change the cam, intake, exhaust, etc and not have a problem.

[fords4life]

I should have written my response differently.  Yes, I know my truck is EFI.  What I was trying to say was I should've looked a little harder at the carburated options before jumping on the EFI......that being said, it was a bit of a 911 purchase due to my F-250 being out of commission and only having a few days to find something to get to work with.

Still learning these older models, but starting to get the hang of how they made things work.  If I didn't have to worry about emissions, things would certainly be much easier....

[85lebaront2]

Yes, and the other problem, 1985.5-1986 5.0L system is all by itself and has a number of unique to those years items. (a) two solenoid valves, vacuum and vent for the EGR, (b) a TPS setting that is extremely sensitive to voltage, (c) no vehicle speed input to the EEC, (d) non-heated O2 sensor in the rear of the right exhaust manifold, (e) system ground is a single two pin plug next to the battery where it corrodes.

EEC itself is wired differently due to some of the differences between it and later models. Some of the items carried over into 1987-89, primarily the fuel system, in-tank low pressure and frame mounted high pressure pump with a reservoir that also provides tank switching for dual tanks.