Spark plug choice and correct heat range

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Hi I currently have a 1978 440rb engine thats been bored .30 over it’s a low compression engine i can’t remember the ratio but i was told they are low I also have edlebrock estreet heads, stock manifolds, aluminum intake manifold, Hughes whiplash low compression cam, aluminum water pump set up, msd distributor and ignition coil, dual electric fans and edlebrock avs2 carb. Im looking for the best spark plugs and heat range for this (street/freeway driven)
 
Seems like an equivalent to the OEM Champion J-12Y gapped to .035"-.040" would work well. I have come to like NGKs over the past years, myself. They usually have a little wider heat range, by observation. With the accessibility issues, an Iridium plug might be a good choice, otherwise one of their V-Power regular plugs. Note, too, that NGK's heat ranges run opposite from what other brands do. Other brands' "cold-to-hot" are "lower number-to-higher number", with NGKs being opposite of that.

In my '70 Monaco 383/330 car, which was spec'd for Champion J-10Ys, they worked fine, but then so did the little bit hotter J-12Ys. No racing or extended WOT, though, other than a normal "through the gears" situation every so often. The ceramic insulators burned light beige in both cases. Just as the J-14Ys did in our '66 Newport 383 2bbl.

Just my experiences,
CBODY67
 
Hi I currently have a 1978 440rb engine thats been bored .30 over it’s a low compression engine i can’t remember the ratio but i was told they are low I also have edlebrock estreet heads, stock manifolds, aluminum intake manifold, Hughes whiplash low compression cam, aluminum water pump set up, msd distributor and ignition coil, dual electric fans and edlebrock avs2 carb. Im looking for the best spark plugs and heat range for this (street/freeway driven)
If it was bored .030 over, weren't the pistons replaced? Is there info on what pistons were installed?

Have you run a hot cylinder compression test? What were the measurements?
 
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