I don't remember the rod or jet sizes but I have been running a Qjet on my 250 for the last four years and it is set up to use on the 4.3 V-6 like the factory used on a 1985 Astro van and a few caddys. That was the last year before they went FI. It is in a 41 Plymouth 2 dr. that I drive all over the country and use it to tow my T roadster. Driven sensibly it gets 19/20 mpg, but if to open it up that falls off quickly. Prior to that I had a Edelbrock that peaked at 14mpg or so.
