Does anyone know what is the correct heat range for the 455 spark plug that is stock? ---------- Post added at 12:09 PM ---------- Previous post was at 11:32 AM ---------- This is a 69 Rivi, I put a 455 in should i run a hotter plug or a colder plug? What I have in there now is a ac delco r45ts and they are gap at .40. The motor is all stock with the no more points distributor stock coil and rotor cap with new edelbrock carb, my problem is that i seem to be burning way to much gas. There are no leaks on the the fuel line so I cant say its going on the ground an im smelling the fumes pretty good when i raise the hood.
What do your plugs look like? id be willing to bet the problem is more with your carb and or timing than the heat range of the plugs.
The plugs are showing white tips, I dont think its the carb because I have two the new one plus the rebuild or reman rodchester.
Heat range varied over the years on the BBB. The R45TS plug was used in many 455's, and for a stock or near stock application, it is ideal. Your plugs would not affect your gas mileage in a negative way unless they were fouling and the plugs were misfiring. Unleaded fuel doesn't color the plugs, so the fact that the plugs are white doesn't really mean anything unless you are having performance problems like surge, or hesitation. Make sure your timing (initial and total) are correct, and that the vacuum advance is operating correctly. That will have a greater impact on your fuel mileage. IMHO, the Edelbrock carburetors are not as good as a Quadrajet built for your application. It's likely that the Edelbrock carburetor is not optimal for your engine right out of the box. It needs to be tuned. Best way to do that is with a wide band O2 sensor.
