[DeTomaso] Intake Reversion

JDeRyke at aol.com JDeRyke at aol.com
Thu May 2 01:50:35 EDT 2013


Reversion is normally found with very strong pulsations from IR-mounted 
carbs like quadruple Webers, not Holley 4bbls. It causes a visible cloud of air 
& fuel to appear 6" or so above the carb throats at a critical rpm. Exhaust 
reversion is harder to diagnose but is normally a low rpm quirk. The 
port-restrictors you speak of can be used in both intake and exhaust, but the 
effect of intake stuffers is usually to sharpen up the midrange and utterly 
torpedo the top end. Exhaust stuffers are less noticable and work best at higher 
rpms. Neither will likely fix the engine problems you mention. Simply going 
lean might do what you describe. What kind of "750 Holley" is this- a 
vac-sec or a DP? You may need a tuner-Holley for that beast; an out-of-the-box 
carb isn't likely to work very well unless you get luckier than I ever did. 
It's also very hard to separate ignition and fuel problems 'cause they give 
identical symptoms. 
As a pure guess, I'll go with JT on this: some sort of carb problem- 
possibly a blown or wrong range power valve. I'd try another Holley and maybe 
different plug wires, too. Good luck- J Deryke


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