That was a very informative post Ymeski thank u. I run premium or 91 all the time. But I guess the way your post explains this I should drop my timing back and run mid grade 89 and time for that. If I'm at all understanding correctly.
I did not assemble the motor from crank to heads It was built about 3 years ago ran in a ranger, the ranger was wrecked and I bought the motor. I talked to the builder and he claimed he couldnt remember the heads used. All I kno is it is an 88 HO block rebuilt with nickle crank and forged pistons and I would assume they are the stock HO heads it was intended to be a very mild motor, cam is just slightly larger than stock. I would assume it's the stock 9:1 compression I don't kno. It has the E threaded spark plug or at least that's what the guys at napa were calling them if this helps at all to identify the heads. I wish I had more information because I love my truck and my HO and would like to keep it running tip top and correctly

 

That's what I'd do. Here's another read for ya: https://www.f150forum.com/f10/about-...ng-bump-53159/

 

Fair enough I guess I will be borrowing a timing light again this weekend and run cheaper fuel. My last question. Will my milage be affected after dropping in octane and timing? Even tho I hear u get 20mpg

 

I doubt more effective fuel burn will reduce MPG's. But I would highly recommend a "Seafoam" treatment. Afterwards, a bottle of Lucas injector cleaner every 4-5 tanks is a good cheap date.

 

The motor is only 7k miles old still seafoam

 

Dang, that's a tuffy. I think I'd hold off on that for a while.

 

Yea I thank. That's what the scanner said

 

My 1996 is clearly obd-ll

 

"It" told you!........ Dang, can you see dead people w/ that thing too?

 

If you hook it up to a computer you can pull any thing you want off of it. Not sure but you can also get milage off of it