Thread: fuel issue

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So I fired up my new 461 on pump gas and had it timed and tuned what seemed perfectly, then I switched over to 110 octane torco race fuel and it barely runs. Will the carb need to be richened up for race fuel, all of my former engine were pump gas motors so the high octane is new to me. A little background on the motor, .404 over 454, flat tops, block decked, 215 heads shaved, 2.19 188 valves and a holley 800 dp with 81/83 jets. the engine is not really over cammed and on pump gas it would idle quite well at 700 rpm.
the only variable I changed was the fuel and it will barely idle. any help would be greatly appreciated.

i have gone from pump fuel to race fuel and back many times with idle mix never played with jets do not come in to play at idle suck up some junk .vacuum leak.did you try turning out idle mix screws out a 1/4 more ?

not yet, I think tomorrow I will pull the front bowl and see if any junk is in there. it seems really strange that fuel would make that much of a difference.

i ran race fuel and back to pump fuel for over 25 years never had it not idle were pump fuel would