FE 390 Plugs

[jhand]

I have an ERA with a stock FE 390 running a 750 quick fuel carb. The sales rep talked me into the 750 and it just seems to big for the car. The car is running well but really rich, I am going to change plugs this weekend and wanted to see what people used, any recommendations would be great. Any info on the carb as well would be great.

thanks
jay

[blykins]

That's the size I would recommend as well. Why do you think it's rich? Rich at speed or rich at idle?

[jhand]

Just by the smell you get from driving the car and I have been told when followed the car has a bad exhaust smell. The pipes are black on the outlet, will pull plugs to see condition, other then the smell the car is running great.

Jay

[blykins]

Carb just needs tuned....they are not perfect out of the box. That's the correct size carb, you just need to take an hour or two and dial it in.

[jhand]

That is my plan, all i did was adjust the floats with the window sights, are they pretty easy to tune?
Thanks
jay

[cscobra]

750 may be a bit large for a 390. I run a 660 on mine with excellent results and no problems out of the box.

[Barry_R]

750 is fine - pretty much perfect size.
If you read plugs & go careful I'd bet it needs to drop 2-4 jet sizes

[jhand]

Thanks for the input, I will let you know how it works over the weekend.
Jay

[Frank Messina]

They're not hard to tune you just need to do things in order. Get a Holley tuning booklet and become familiar with the process. Check the online Holley catalog to determine what size jets and power valve came on your carb and make sure you have an assortment of jets on hand to cover what you intend to do. The idle circuit supplies gas all the time so that's where you start. Familiarize yourself with how to properly set the idle mixture. It's often too rich out of the box. Once properly set that may fix your condition and you can stop right there. If it's still rich after that, then look at the main jets, but make changes in small steps. No more than two jet sizes at a time. If two is too much back up one, if not enough go two more. Only work on one thing at a time so that you "don't lose the rabbit". Idle, then primary, then secondary, etc.

Frank