mayberg

Gentlemen,

I'm pondering a tune-up of the 454 this spring. I've got the requisitie oil-burning big-block - most likely valve guides - and I know I'll have to address that situation sometime.

In the meantime, I was pondering whether running a hotter plug would help with burning off the oil from the plug so she would run better. The stock plug for my 454 is AC Delco R44T and that's what's in there now (and I haven't pulled one lately to check, but I'm sure they're oil-soaked). The engine is stock, with the exception of a lopey cam. It runs and idles fine, but there a lopey rumble to it (which is fine with me) not the purrrrr of a stock 454 for 1974.

So, what do you think? If I should run a hotter plug, what's the number? What is hotter? R45T or R43T, or something else. I plan on staying with AC/Delco plugs for now.

Let me know your thoughts. Many thanks. GM

bence13_33

I too would like to know the answer to this question because I have a 454 big block that is fouling plugs at low RPMs and would like to know what heat range to step up to.

verskel

R45-ST's are 'hotter' and the R43's are "cooler".......

The R45's will work the best based on your post. :thumbs:

Larry B.

If you are not driving it too hard you can go up one or two heat ranges with good results. However... If you want to race or run hard then that could cause some pre-ignition. You want a cold plug for racing and a hot plug for city driving. Also... Auto lite plugs seem to tolerate oil much better than A/C's. Actually Auto lites are a better plug. See what everyone at the track runs... Lots of Autolites.

Gary79

you could try running a set of AC rapid fires, i had a valve seal problem on my 94 Suburban and Rapid Fires helped until i got the seals replaced.(altho a little pricey)