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Old 10-02-2018, 02:11 AM   #112 (permalink)
JSH
AKA - Jason
 
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Join Date: May 2009
Location: PDX
Posts: 3,601

Adventure Seeker - '04 Chevy Astro - Campervan
90 day: 17.3 mpg (US)
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Quote:
Originally Posted by racprops View Post
Well when I consider how bad the TBI system is, that a TPI stock is rated to give 30% better MPG which if true that works gets me to 18.2…on a bone stock engine, now add in my changes to a new strong 383 tuned for lower RPM Torque, add in the modified PCM with a lean burn cruse, I think I will hit 20+ MPG.

NOW add in the 8 gear auto and the high rear end with a 2.14 to 2.23 I think I will be able to see much more…

Rich
If you are shooting for 20ish mpg highway I would just swap in a Chevy 4.3L V6 and call it a day. Your 1993 G20 with the 4.3L was rated at 20 mpg highway from the factory. 4.3L V6's are a dime a dozen in junkyards.

I've done 20-22 mpg with my 2004 Chevy Astro (before the lift)
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