Use to run NGK's in my street and race car stuff years ago but went to Champion with my new stuff because that's what Edelbrock and 440 Source recommended for their heads but they just seem to foul way too easy!! Both my combos run on pump gas and both around 11.0 comp. race motor is a 500 ci with CNC'd Eddy heads, roller cam and tunnel ram, street motor is 448 ci with ported Stealth's, solid cam and EFI. What do you guys recommend besides Champion RC9YC and RC12YC.
