spark plug size matter?

Hi, i was told an easy way to tell if a 460 or 429 has the good heads and high compression is to check the spark plugs if it is the big plugs it is high compression small plugs low comp... this if an engine is stock from the factory.

Is there any truth to this?

This same person said my 429 with head numbers d ve that is missing the second letter is an experimental engine and hard to find. So i am not sure how much to believe! i am not sure why the letter is missing on both heads.

Thanks for any help

I have and have seen others grind off a letter on the casting numbers to keep my competition(chevy guys) from knowing which heads I was running. D0VE, C9VE heads use the large headed plugs, D0OE, D2OE,and D3VE heads use small plugs,not sure about D2VE heads. So plug size will not determine compression.

ok thanks he didnt buy an engine i had for sale cuz it had small plugs and was not a high compression engine he said. So without looking inside say u can't tell what cc's the heads are? say a set of d3's. there was 2 diff. cc's in the heads and this is the diff. in comp. right?

So his theory about find big plugs ya got high compression doesnt work!

What the guy is telling you could or could not be true. The early heads on the 429's were C8/C9/D0ve and were pretty much the same (small combustion chamber) head w/big plug and made higher compression.The D00e-r was also a small chamber head w/small plug. I don't know alot about the D2 #'s.Just that one was a good PI head and the other was a pos.

If I remember correctly
c8/c9/D0VE heads were approx. 75 cc chambers
D0OE(cobra jet) heads were approx. 72 cc chambers
D2OE(police interceptor) heads were approx 88 cc chambers
D3VE heads were approx 95 cc chambers
D2VE heads had some big ol soup bowl chambers I believe around 120 cc

As far as I know all the D3VE heads had the same chamber size.

lghting94 wrote:If I remember correctly
c8/c9/D0VE heads were approx. 75 cc chambers
D0OE(cobra jet) heads were approx. 72 cc chambers
D2OE(police interceptor) heads were approx 88 cc chambers
D3VE heads were approx 95 cc chambers
D2VE heads had some big ol soup bowl chambers I believe around 120 cc

As far as I know all the D3VE heads had the same chamber size.

D2VE is a open shallow chamber , about 92/95 cc's , take the 18mm large plug (13/16 hex)

Thanks Dan H for the clarification I wasnt sure on the D2VE heads as I have only ever seen one set many years ago.