I am thinking about converting my F150 '89 302 from speed density to mass air. I want to do this in order to increase (1) mileage and (2) performance a bit.

My main concern is future smog checks. Will a converted truck pass?

I would grab the parts from a mustang or '95 truck from the junkyard or buy the Ford upgrade kit. Does either path make a difference?

I am also doing the other things to help mileage: insulating the air box; high flow air filter; tonneau cover; maybe new PCM upgrade; hotter coil; 8.0mm spark plug wires; new distributor cap; radial tires (!); and new airbox intake from an F250 351.

Thank you,
Lance

 

It would help if you would tell us in which state you are getting it plated. Rules vary by state. In some you'd have no problem as long as it passed the sniffer; in some others you'd wait till hell froze over before you got approval regardless of how clean it was.

 

Here in NY you don't have to worry about 1996 and older vehicles. Newer vehicles get plugged in and scanned. No codes= you pass.

 

OOPS!

California is my state.

Last year the truck had the same level of tests as my '96 Volvo and '03 Explorer. Check to see if the "check engine" light works; pull codes; O2, CO2, NOx level checks from the tail pipe; timing; gas cap pressure check; and intact pollution equipment presence check (AIR, PCV, EGR)...

-Lance

 

a tonneau cover won't help your mileage and driving with the tail gate down will hurt it.

In the box air circulates right behind the cab creating a kind of bubble that faster air flows over if you install a tonneau cover you get no improvment but it shouldn't hurt either. so don't spend money thinking you are going to save money. I don't like covers. if thats the only reason to get one then well you shouldn't

 

A tonneau cover makes an almost 2 MPG difference in my truck at highway speeds, no difference to speak of around town. Literally, YMMV.

 

Unless there have been changes to the laws that I'm not aware of, you will have a very hard time getting your truck smogged in California if you switch from SD to MAF.

 

California has tough laws. I'd venture to say that if any state will give you a hard time on the emissions, it will be California.

Personally I wouldn't do the swap regardless unless you have more extensive mods planned. The MAF trucks don't seem to get any better mileage than the SD trucks and the money would be better spent on mileage and performance mods that do work.

My bed cover helps, I've documented mileage increases on my last two trucks with them.

Underdrive pulleys helped, as did ignition mods.

Yikes! If you don't have radial tires that alone should improve MPG.

 

PKRWUD, signmaster,

I will take your recommendations. No S/D->MAF switch for me!

It'll just be distributor cap, plug wires, and a bed cover for me. I put in the K&N drop-in filter and a F250 air-box snorkel already. I can feel a difference.

Yes, I just got Michelin LTX radials. They handle and ride a lot better than my 15 year old bias belt tires. I had some more mileage on the tread, but the tires developed concentric cracks on all the sidewalls and I would lose control over 50 MPH.

Thank you again!
Lance