I have an '86 F-150 with the 302 EFI. I don't have a tach in my truck. It's got a 3.50 axle ratio paired up with the manual 4-speed with low (NP435 or 325, I can't remember the numbers).

The truck is geared pretty low. Pathetic gas mileage when going 55 mph. Well, I'm not asking what I can do to increase my MPG, as I knew that I would have to deal with that when I got the truck. I'm just wondering... can this truck go down the interstate at a sustained 70 - 80mph without causing any damage? I have no clue what RPM I would be riding at, but maybe someone else can clue me in here. I can't remember what size tires are on it at the moment, but they seem to look a little taller than on most trucks like this I see. Maybe it's just me, but either way, who else has a truck with this gearing and takes it down the intersate at 70+mph.

I might be getting a job where I will have to ride 45 minutes on I-81 where the speedlimit is 70mph. I have a motorcycle... but I'm not riding that in the winter time. Sure, I can get a little beater car... but until then, what do you think about this truck at those speeds for 30 - 45 minutes?

Also, for a truck with this gearing, what kind of oil would you recommend? Is 10w-30 thick enough, or do I need to move up to a 40 weight? I have good oil pressure, but I don't know what oil is in it. I haven't had it for all that long. Has a Kendall sticker in the window, but doesn't say what weight was used. I'm an oil fanatic and love to change my on oil, ensuring the job is done properly. And I like to know I have a good weight matched up for the engine, lol. What weight oil do you guys use?

 

My truck is similar to yours, except no EFI and has an AOD tranny. I can curise at 70 all day if I want, and I have even towed at those speeds in 3rd gear (the same as 4th in the 4 speed stick shift). RPMs @ 70 mph with 235/75/15 tires, and NOT in overdrive is 2850 rpm.

Ideal for this 302 is usually 2500 rpm (or less), but they can cruise over 3000 if needed, they have a short stroke for their size, and can easly handle those RPMs.

I run 10w30 oil and always have, don't know what advantages there would be in switching to anything else.

You might consider trying to cruise at 60 mph instead, fuel economy will be better, it you can stand getting past by everyone (not easy i realize).

 

Thanks for the reply. So, my 4th is practically geared like your 3rd in an AOD. So, I'm probably under 3000RPM @ 70mph, that's good to know. I was hoping it wasn't something like 4000+ RPM.

This truck is geared pretty low in the 1st - 3rd (1st, especially, duh... I never use it), and 4th doesn't seem ALL too bad, but you can tell you are where the 'power is' when cruising @ 55mph, so I was just curious about what RPM I might be pushing at 70mph. Thanks, again. And if anyone else has any input, please go ahead and share.

 

I think you would be fine cruising at 70. As long as you keep up on the fluids and pay attention to any odd noises or leaks, your truck is fine. Also 10-30 is a good choice thats what I run, but you might consider a synthetic if your looking for a little more mialeage and protection.

 

Yeah, this motor is in excellent condition. I think it's just hit 110,000 miles on it. That's awesome, to me, for an '86 model ANYTHING. I know this 302 has a lot of life left in it. And it's pretty peppy. This truck will spin the tires from a low roll in 2nd gear... not that I hot rod it, but ya know. We gotta feel the power now and then. Not bad for a little 302. I would switch to synthetic but lots of peopel feel that it will clean the seals and seals will start leaking. I don't know, never experienced it. If it wasn't over 20 years old, I more than likely would run synthetic in it. I guess I'll just use what I use in all my other cars... Castrol GTX 10w-30. Any objections?

 

I object....waste of money. Just buy the SuperTech oil at WallyMart and quit paying for those glossy magazine Castrol ads. I've used house brands for 45 years, never any trouble or burning of oil. Have you ever heard anyone say "Yea man, my engine blew up cause I used house brand oil"?
It very well may be made at the same refinery...I know there's no refinery in Bentonville, Arkansas.

 

I personally refuse to use Castrol GTX I don't want to start any flame wars about oil brands and it may be a coincidence but I have blown 3 motors in my life time and they were all on Castrol GTX. I used to switch brands based on various studies and I had a Triumph sports car that specifically called for GTX. I switched all my vehicles to it at that time and all three threw rods, spun bearings and clunked out on me. I have run Quaker state, Mobil 1, Pennzoil and Wal-Mart cheapo and never had this happen in 40 years. I later researched GTX and found that they contract out their "blend" to various refiners so they aren't even the ones making it and the quality can shift from one maker to another. Same ting may happen with some cheapo brands but at least you aren't paying top dollar for it.

I personally use synthetic in the vehicles that will run it without buring it or leaking it and use Penzoil in the others. I couldn't care less and may switch brands tomorrow as long as it isn't Castrol GTX.

FWIW - One of the blown motors was a Triumph straight 6 that is supposed to be bullet proof. The other two were Chevy ( I know Boo Hiss) 3.5L that was also supposed to be a reliable motor.

My 86 F-150 truck runs Mobil one and only leaks one drop on initial shutdown from the rear main but won't leak on Pennz so I run the synthetic in it anyway putting up with the leak to get the added protection and milage. My Mercury 4.6L burns synthetic so it is on Pennz. Don't know why the newer car burns the syntetic and old truck doesn't but both motors are in great shape and on "normal oil" don't leak or burn a drop between changes. Just one of those things that make you go Hmmmmm.

PS - those Chevy 3.5L rn OK but they leak like strainers if you push them like a Ford. If you drive like a grandma I guess they do OK but they can't take any lead foot action or seals blow out left and right. I'll never own another Chevy!!! I changed every seal in those things at least 3-4 times. Go Ford!!

Good Luck,

Lee

 

Are you reffering to a synthetic oil, or do you figure castrol just a bad brand in general?

 

I know a lot of people that hate Castrol because of what they thought of them 15+ years ago. Is this the time you all are talking about Castrol being bad?

I ask this because... and hear me out... on bobistheoilguy.com, Castrol GTX 10w-30 gives some of the BEST used oil analysis on that website. I won't bore you going into detail about bobistheoilguy, but either some of you will already know about it... and the others will go there (smart choice) and look at people's tests sent in on their oil in their cars.

Again, I'm not arguing that Castrol GTX is a good or bad oil. Some of you... it must have done you bad. As for me, in the last 5 years, it's all I have used. And... sad to say, but I used to run the absolute crap out of my cars and they never had any problems. Namely my 1991 Dodge Stealth R/T 3.0 V6 DOHC non-turbo (I had to others with twin turbos), but this non-turbo took such a bad beating, I feel bad for it now. It went from 120,000 miles to 190,000 miles, all from me. I swear it saw 7300RPM every day, multiple times. Castrol GTX only. Still has great oil pressure.

But, it could have done the same with ... Havoline, Valvoline, Quaker State, Pennzoil, etc.

BTW, I've got to ask, you guys that like Pennzoil and hate Castrol... are you in your upper 30's, lower 40's by any chance?

I asked for any objections and I got them. Again, I don't want to come off like I am arguing, becaues I'm not. I, too, want to find the Holy Grail of conventional oil. Be sure to check out bobistheoilguy.com.

 

I wont use QS or Pennz, My mother bought a brand new F-150 in 1995 and we ran only those brands in it. I had to change the valve cover gasket at 110k miles, and there was a ton of sludge in the top of the motor. Those brands use parafin wax, and it accumulates over time. I have been running Valvoline snythetic blend, but am now switching over to Royal Purple. I'll be redoing the valve cover gaskets on my 79 Capri(302) soon, which I have been running the Valvoline Syn blend since it was rebuilt and see how it's doing. I replaced a head gasket on it at 30k miles, and it was still nice and clean, should have about 80k miles now. Oh, and I'm only 28.