What are the possibilities for an 85 300inline 6?

Well I have owned both in the past, 1979 300 inline and a 1977 460, the power in the 460 is no comparable to the 300 it hauls ass! but you will pay for that power at the pump they are horrible on fuel mileage, mine was averaging 9MPG and it did let me down twice for jumped timing (new timing gears & chain) and running hot alot but my 300 was good on fuel and never once let me down. If money is no object I'd say go for the 460, but I recommend the 300 inline.

a 300 in good condition is actually a pretty impressive engine. There was a company back in the day that used to make performance parts for the 300 called Clifford's performance. I am not sure if they are still around or not but if they aren't I'm sure someone picked up where they left off. I personally would stick with the 300 or go to a small block. the 302 and 351's are pretty strong reliable and have tons of performance goodies available for cheap and I believe should work with the trans you already have. What ever you choose I would be sure to keep your current axles for off-roading. The I6 trucks typically ran lower gears and would be preferable for trail running.

I have seen 300-6's getting over 300,000 miles on thme. I have owned 2. A 1980 and 1986. One was an auto and the other a 4spd(w/OD). They were both tough engines and easy to maintain. I had to replace the head gasket in the 1980 and was done changing it in 3 hours. With these economic times I wish I had a Inline 300 right now. However, like another person said, if you got the money the 460 will get you where you want fast. Good luck.

I had a 85 wit a 300 was da best trucks me owned and got great mileage and me took a beating and kept and goin I have a 85 f250 wit a 460 to love both prefer the 300

well you can get a 4 barrel intake for the 300 but seeing you have an 85 you have a feedback carb system like mine. if you wan't to keep the six and add hp. get the 4 barrel intake, replace the rockers with a set from an 85 chevy c 10 with a 250 ci. but your also going to have to change the dist,[non moduel with vacuume advance] moduel that bolts on fenderwell, [has to have the blue grommet] wiring harness[i believe between about 79-83] for dist to moduel to coil. also going to need a coil and bracket. [round coil]. you can find the wiring harness new online but it's not cheap. but the chevy rockers will give more hp and should cost about $50.00 for the set at a parts store.[if you just wan't to add a little hp and not spend much]. but if you wan't to put the 4 barrel intake you will need the other parts because it's a feedback carb.[this change over eliminates the computer] don't know what your emissions are in your state. [as far as my state i don't have any problems because of year]