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Join Date: Oct 2017
Location: Traverse City, MI
Re: Tune up 83 454 RV engine
What you most likely find is a dish piston and Open Chamber head, actual compression will be in the 7.3-7.5:1 area. The 781 are good heads, I would look for something like an Xtreme Energy (Comp Cams) or as mentioned the HE268 that are designed to increase cylinder pressure in low compression engines so they behave more like a high compression engine. Add headers and dual exhaust, put a faster curve in the distributor (lighter spring) and dial down the static timing and get the proper jetting for the combo - they normally came on the lean side.
Back in the late 1970's my father bought a C20 Suburban for towing his horse trailer. He was not happy with the power or mileage so I took the liberty of putting on long tube headers, dual exhaust, recurved the distributor to come in faster and re-jetted the carb. Left the compression where it was, even with the stock cam it would get 13 mpg (TH400 and 4.10 gears) and would tow like crazy. Had to haul a horse from Wisconsin to California, even with a loaded trailer though the mountains you could maintain speed!