What Depth Spark Plugs? 327 With 962 Heads

[ShortCST]

I'm looking at shorty spark plugs to sneak underneath my Doug Thorley Tri Y headers, and noticing that there are two depths of threads. Will the deeper ones fit? I'm thinking that they'll increase the compression ratio a smidge if they do (by sticking out further into the combustion chamber, thereby shrinking the size of the chamber a bit), with the related benefits.

[Warrens69GMC]

Sure on the 962 heads? Not 062?

[ShortCST]

Originally Posted by Warrens69GMC

Sure on the 962 heads? Not 062?

Oops. I meant 462. The old iron double hump 2.02 cylinder heads.

[AussieinNC]

Champion RJ6C
or
Bosch WR8EC
or
AC Delco R43

All should be gapped at .035

Dont use long thread plugs in these heads...they will either cause piston to plug interference and damage or the threads will fill up with carbon and make removal almost impossible...have also heard of threads glowing so hot they cause pre-ignition...

Stick to correct length plugs...safer

[ShortCST]

Originally Posted by AussieinNC

Champion RJ6C
or
Bosch WR8EC
or
AC Delco R43

All should be gapped at .035

Dont use long thread plugs in these heads...they will either cause piston to plug interference and damage or the threads will fill up with carbon and make removal almost impossible...have also heard of threads glowing so hot they cause pre-ignition...

Stick to correct length plugs...safer

Perfect, thanks!

[Steeveedee]

Originally Posted by AussieinNC

Champion RJ6C
or
Bosch WR8EC
or
AC Delco R43

All should be gapped at .035

Dont use long thread plugs in these heads...they will either cause piston to plug interference and damage or the threads will fill up with carbon and make removal almost impossible...have also heard of threads glowing so hot they cause pre-ignition...

Stick to correct length plugs...safer

Yup. I know some people who have done that. It was an iron fence company that had a V-8 put in a '60 Chevy that came equipped originally with a 6. The guy who ran the company wanted to save money and had one of his parts changers (cement workers) put plugs in it. Since the '60 would have only had a 348 or 409, when the guy bought plugs, he got the 3/4" reach plugs. Even if they didn't interfere with the pistons, they'd run hot enough to cause serious detonation. Dude didn't know the difference between a big block and a small block, and probably just shrugged when he saw the different size plugs. It came to us because it was running rough and leaking compression past the plugs. It was a later model engine with tapered seats. The owner started bringing his equipment back to us, after that.