After reading many, many articles on E85, I don't think I should be to concerned if I start using E85 on the truck. Everything I've read so only advocates against it if the engine used fuel injectors. A '91 5.2L uses throttle body injections, right? If I am correct, couldn't I also raise my compression ration in order to take full advantage of the 105 octane rating?

I'm asking all of these questions because I'm considering the purchase of an older Dakota and would more than likely rebuild the engine in the near future.

 

You have the right ideas
and the concept of modifying the older TBI is sound.

You do need to bump compression to get full benefit
and might be able to go as high as 11 to 1
if gasoline is never to be used again.

The inside of your old fuel line was not meant for ethanol
and you might want to imitate the Ram 4.7 Flex Fuel version
and use a PTFE inner lining (similar to TEFLON)
on a replacement tank-to-TBI hose
from a custom shop
to resist long term attack by the ethanol.

With the older truck it might be relatively easy
to boost fuel line psi higher
to compensate for the E85.
Remember than fuel injector flow
is proportional to the square root of pressure.

To get the air to fuel ratio right
you would get more dependable results
by purchasing or borrowing a 'wide range' oxygen sensor

http://www.carcraft.com/techarticles/116_0402_tune/

stored at

http://tinyurl.com/2lodlp

or

http://www.nightrider.com/biketech/i..._lm1_intro.htm