71MonteCarloMD Posted September 2, 2015 Share Posted September 2, 2015 I'm wondering about my 350 4bbl since the previous owner rebuilt the engine and swapped 2bbl with 4bbl maybe 12 yeas ago. Is there something I need to check and modify for when using gas with Ethanol? Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted September 2, 2015 Share Posted September 2, 2015 It will probably need premium but you have no worries Quote Link to comment Share on other sites More sharing options...
71MonteCarloMD Posted September 3, 2015 Author Share Posted September 3, 2015 Thanks Sam, will use premium at all the times. Quote Link to comment Share on other sites More sharing options...
mikenewman Posted September 3, 2015 Share Posted September 3, 2015 My 72 is now a four barrel 350 it runs fine on 87 octane gas with a little timming change Quote Link to comment Share on other sites More sharing options...
Leghome Posted September 3, 2015 Share Posted September 3, 2015 My 72 with 350 4 bbl also runs fine on 87 Quote Link to comment Share on other sites More sharing options...
cny first gen 71 Posted September 3, 2015 Share Posted September 3, 2015 Mine runs fine on 87 but I always try to put ethanol free which is premium it gets better gas mileage and a little better performance 350 4 barrel now was originally 2 barrel Quote Link to comment Share on other sites More sharing options...
72-CLASSIC_RIDE Posted September 3, 2015 Share Posted September 3, 2015 Running a 402 CI 4 bbl Carb and use pump gas regular unleaded 87 octane and performs fine. I used Premium fuel on occasion just to see if there was a performance difference but did not discover any major difference. No pinging under load either..............You should be fine with stock motor  Doug Quote Link to comment Share on other sites More sharing options...
stangeba Posted September 3, 2015 Share Posted September 3, 2015 I get a bit of spark knock but mid grade takes care of it on my all stock 71 350 4BBL. I should take a look at my points and dwell and timing, the points are over 15 years old. Bruce Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted September 4, 2015 Share Posted September 4, 2015 yes you "can" run it on 87 but these older engines like a little more, so why chance burning a piston, ethanol also leans out the fuel mixture slightly Quote Link to comment Share on other sites More sharing options...
Jared Richey Posted September 9, 2015 Share Posted September 9, 2015 72 you might can get away with 87. 70 forget it, 10:25 to 1, needs race gas to run the best in reality. Quote Link to comment Share on other sites More sharing options...
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