ks114

Hi,I bought a 1979 with a 383 Stroker. Runs great, but pings. We tried retarding the timing a bit, but it still pings. It has cast heads and, according to the rebuilder, has 9:1 compression. I haven't pulled a plug yet, but thought I would check and see what plug would be good for this. R44?

BlackC3vette

Have you checked for the total timing? That would be a combination of the initial, mechanical and vacuum advance. It's best to use a power timing light.

gkull

I doubt that you have a 9 cr 383 because it would need custom deep dish pistons required. The fix is a bigger duration cam

fishslayer143

93 octane will solve it ... my 383 has 10.5:1 Comp Ratio no ping .. make sure you have no more than 34-36* total timing .....initial+mech adv

Matthew Manney

When it comes to the spark plugs and the pinging it should not cause it unless you are way off on the heat range. As to what type of plugs in accordance to heat range that your engine likes the best i go by what David Vizard says in his holley super tune book. "the spark plug should run at a temperature to ensure deposit burn off and no hotter"

cv67

When you pull a plug if you look at the strap on the outside you may see what looks like a light stripe if you get a chance post a pic. Tells a little about timing. If its 9:1 even 9.5 bet you can tune it out.

Buccaneer

I would look at this first and see where you are before trying to T/S.

gkull

Why I said compression is because your budget 383 rotating kits are 11 to 1 with 64cc and 10.3 with 76cc

No amount of timing retard can fix a small cam and stock heads. I've seen this over and over with people doing budget 383s

ks114

This engine was built by by Chet Wilson Engines in Wichita. The builder (Jerry Wilson) stated that it was 9:1.

gkull

Chets is just another machine shop trying to make a living if you have stock head's and an externally balanced engine damper. You have a very cheap budget build 383

If you have 9 to 1 R44 or 45 plugs will be fine

Get a dial type timing light and see what the timing is at 3500 rpm with the vacuum advanced off

larrywalk

Because of the many types of heads, some take short reach, but some take a longer reach spark plug. Before buying, ensure a couple of things:
1. Does it have a flat seat or tapered seat?
2. Measure the depth of threads in the spark plug hole. Some old stock heads have only 3/8" of threads; some later stock heads have tapered seats needing a 1/2" reach plug; most aluminum and some aftermarket cast iron heads need a 3/4" reach.

Make sure to get this right because if you use a short thread plug in a long thread hole, it won't run very well.