[gumby79]

I've been thinking it would be easyer to pick up any truck of this body style and stuff my Dodge parts in it than to adjust the stack of bricks body I have now.
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Look into a MSD ignition system as a mpg mod(I ran a 6 Digital it has a friend mode flip a switch and 3000 rpm secondary rev limiter primary was set to 5000rpm in case of u-joint failure) . More complete combustion= better mpg . I was able to drop to 87 octane from 91 octane on my 79 chevyK20 =20-30c per gal cheaper (not mpg but more $ in my wallet just the same)bump my timing up to 14° epa called for 4° with the stock HEI set to 10° 91 was required to stop pinging as I had 10:1 CR. At 14°pulling a 33' 5th wheel at 21,000lbs gross on 7-12% grades without pinging.
Disclamer I also in stalled a RPM Air gap intake ,TH400 w/low stall tork converte built to a 450hp speck (800rpm stall, idle set to 500rpm except the alt, it was happy down to ~425 rpm ) and NP 205 (in place of a NP203) these mods resulting in an increase from 7.4-7.6mpg to 10-14....in short