Hi all.

New to forum and would like to ask a question.

I have a 86 f-150 with a 302 that I am restoring. Have finished the body and now would like to begin on the drive train. I would like to add some more power to the 302 but with the air density system, I'm not sure what can be done without disturbing the computer. Am I correct that the system cannot handle porting heads, cam upgrades, and headers. If that is the case then possible I should junk the computer and go carberated. What is your opinion.


Ron Clark

 

Ron

I just got finished this year on upgrading my 1986 F150 4x4 with a 302.
Everything. I had a few headaches with the motor upgrade but I will tell you what works rather than what does not!

On the motor
The 302 with the older computer (Air density system MAP) will take a few upgrades. The best and the easiest is headers and dual exhaust. The computer will handle this with no problem. Recommend you Get a new O2 sensor

The next upgrade and this is as far as you can go with this computer, is a mild cam. I used a Crane cam, Promax 2020 (Non HO). It has a few quirps but the computer will handle it with an adjustment in the Timing advancement. I set the advancement to 12 deg after a few test runs (spout connector removed, Stock is 10 deg). Compression 10.1 to 1 so I needed premium fuel
Motor dyno was 242 hp which was alot better than the stock in 1986 of 185 hp
My 302 was originally built to 1989 Mustang specs and I made mistake of putting in an HO cam. (Had to switch back to a non HO cam as mentioned above) This will not work with the 1986 truck computer. It will work with a 1996 or new truck computer and wiring harness that has a Mass air system.

It is cheaper to go to a carb system if you want to go any further. But if you can get your hands on a Truck 1995 -96 motor with Mas air, computer and wiring harness EFI works great.

If you have any other questions, send me a line and I'll try to steer you in the right direction.

Regards
Bruce P.

 

Thaanks for the info. I wasn't going to go too far. just a crane power truck cam, headers, duals, and possible exhaust porting the heads and 9:1 compression. I had seen on other forums that the 86 computer couldn't handle more than dual exausts so I wasn't sure how far I could go. Not interested in creating a hot rod, just hoping to increase the efficiency so I could get 225 or so horse power with maybe a little better gas milage.

 

I recently bought a 1986 XLT Lariat with a EFI engine. It had a bad rod knock.

I put in a stroker crank, KB366 pistons, and new longer rods. Got all the parts from The Mustang Depot. I dind't buy the balanced stroker kit, and to do it over I would have, it is cheaper in the long run.

I put in a Mustang camshaft with roller lifters and changed out the distributor for one with a steel drive gear, I have been told that if you use the distributor with the cast gear it won't last long on the Mustang camshaft. The cam and lifters were from a 1987 Mustang HO.

The firing order changed to that of the Mustang motor, but it starts and runs great. I am going to put the factory Mustang headers on it soon and get dual exhaust run all the way back with a Mustang H-pipe.

I am using the stock intake and heads that were on the 302. I had the heads re-worked by a local machine shop. Stock electronics as well. No changes made except for the mechanical stuff above.


Hope this helps,
Paul

 

How much power did you get and what did the mods do to the gas mileage and emissions? This truck will be a daily driver -50 miles round trip to work and I don't want to kill the gas mileage. I already have 341 rear gears.

 

Single 3 inch exhaust will deliver better power for everyday driving, and IMO sounds nicer than dual exhaust. A single 3 inch pipe with high flow 3 inch in and out muffler has more flow capability than dual 2 1/4 pipes. You can always get a y adapter made for the headers, and it will run roughly the same dollar figure as the duals will.

 

I really can't speak of a change, because when I bought the truck the engine was trashed and I never drove it.

It had some bad gas in it for several months and I am still driving it getting all the gas out...

It has a very slight miss in it at idle, I have heard that many of the Mustangs had a rough idle as well. It gets up and goes when you hit the gas though!

I only have 500 miles on it so it isn't really well broke in yet. The truck I have has 3.08 gears in the rearend so that will have an effect on gas mileage. As soon as I get it broken in and tuned right, I will post gas mileage and such....

Paul

 

Kthef (Question for you)
I posted a note earlier in the messages and mentioned I never changed the computer or distributor but put an HO cam in the rebuilt motor (By mistake). The motor ran terrible because the timing was off, both ignition and fuel injection (So I was told). I was told there were only two ways to correct this
1) Change the Cam to a NON -HO (Which I did as it was the cheapest)
2) The other was to change the distributor, computer and switch to a MAS air flow system (Twice the cost)

You mentioned you only changed the timing and/ or distributor and it runs fine. Is this correct?

I have 3.55 gears and get around 15 mpg. The T18 direct tranny doesn't help with gas milege either but it gets up and goes (empty) but I know it does not like to pull heavy loads (Thats' the lower torque ci 302) Maybe I should have looked at a 351?? It does it OK but with a noticeble loss in acceleration.

I will be curious to hear your gas mileage.

Bruce P.

 

If you put in an HO camshaft, either on purpose or by mistake, you will have to change the firing order. This may have been what caused you to think the timing was way off. If you use an HO camshaft with the old 15426378 firing order it will buck like a bronco and never run right!

If you use an HO cam, or a Mustang cam (same thing) you will need to use that engine's firing order which is: 13726548.

I do have a little roughness at idle but I haven't had much time to sort it out. I have reset the comptuer recently and it seems to be idling better.

It starts easily, and runs great... Stomp it and it throws your head back!

Like I said earlier, I bought the seperate components from The Mustang Depot, not pushing them, but you could go out to their website and look around. I found them on Ebay. They have complete balanced stroker kits for the Mustang 302, I should have got a kit, but I didn't know what I was doing originally.

I got a used cam/roller lifters out of a 1987 Mustang. You could probably get the distributor with the steel gear from a donor/junkyard as well. I bought my new distributor with a steel gear from Autozone ($90US).

You go to them and ask for a new distributor for the 1986 F-150 WITH A STEEL GEAR. A well respected Ford machinist around here told me that if you use the stock cast geared distibutor on the Mustang steel crank it will shatter the gear within a couple hundred miles. I have had enough problems so I didn't question it and just bought the distributor.

We bored mine .30 over, put in Keith Black 366 Pistons with longer rods and a stroker crank. I had it balanced and had to buy a new flywheel and harmonic balancer. I put on a high volume oil pump as well. Used the stock intake as the Ford guy says the F150 intake produces more torque than the Mustang intake.

Right now I have the stock exhaust manifolds on it but I have a set of the Mustang factory headers that I am going to have fitted some time early next year. I am going to get some new cats and some flowmaster mufflers and then take the lot down to the muffler shop for fitting.

My truck has 3.08 gears in the rear and the C6 tranny.

Paul

 

Sorry, I didn't address your fuel timing question.

According to my friend, the injection system in these pulses fuel to ALL cylinders at the same time, it doesn't pulse them in any order. He also says that most cars pulse all injectors each time and not in a firing order. He says only newer cars and expensive cars with sophisticated comptuers and sensors will pulse JUST the cylinder that is ready to fire.

I know that my truck ran on the old firing order with a bad rod knock, then when I put in the HO cam and changed the firing order it still runs fine.

I have set the timing to 10btdc according to the manual, but my truck doesn't like it and knocks. I advanced it to 19 or 20ish (did it by ear) and it seems to like that setting better.

I set it to 10, got in it and floored it and it knocked heavy under load. I just kept advancing it little by little and stomping it and doing that until it wouldn't knock under load. Only took me a couple tries to get it right.

Paul

 

Kthef
Thank you for all the info
Yes I put and HO cam in by mistake but later understood the firing order had to change. Tired this (Timing change) but still had a rough idle and over fueling. I think due to the fuel injection timing ?? Not sure
Therefore I went to the Promax 2020 Cam from Crane which is a mild recreational cam NON-HO. Same lift and duration spec as a 1989 Mustang but old firing order for my truck. This is a roller cam and runs great.
I wish I had your information earlier.

Seems to run good now- Advancement is set at 13 deg (seems best here) The stock TFI unit apparently is a little bit of a problem as it does not advance the time up enough during high revs (Again so I've been told??) Low revs inder 4,200 grand are fine.
Running dual exhaust 10.1:1 compression and stock intake. Running premium fuel and with no ping at the set timing.

I think this is about as far as I will go as the truck runs good and strong. Got the HO Cam left over as it is of no use to me unless I want to do up a mustang motor. Know of any one that needs one?

Bruce P.

 

This is all good information before I begin redoing the motor on my truck. I had heard that you couldn't do a lot of modifications with a speed density system. Surprised that the system took a stroker kit and cam upgrade without complaining. Maybe because you didn't go too wild on the cam and used the stock heads. Stock Ford 302/351 heads are notorious for restricting exhaust flow and possible kept the mods from over powering the system.

Still undecided which way I want to go. If I stay stock then I will end up buying a rebuilt engine. I can get a long block with a 6 year warrantee for $900.

If I decide to go the modified route then I have a HO block to rebuild and I wouldn't want to spend a lot of money for machine work and parts unless I went all out. Right now looking at a 9.3 compression ratio kit with speed pro pistons, crank and rods from Summit, a Crane Power Max roller cam, Crane roller rockers, headers, and Roush heads. I am sure this combination will require a custom chip but if spending $2500 dollars on an engine why not spent another $300 and make it all work right together.

I don't drive that fast anymore. Too many cars on the road these days. But it sure is fun to see the look on some teenagers face when his latest modified rice burner gets shut down at the red light by some old guy in the old Ford truck.