spark plugs

i need some help finding the right size and right plug for my 72 PI heads Cast #D2OE-AB.. please provide part number with brand

I ran autolite racing plugs in mine if I remember correct they were ar134 part number

do you know if the thread size was 14mm or 18mm? I am sure my heads are 18mm but not too sure because my machinist has it.

Mine were the small plugs.

My D20E's are 14mm plugs.

ARF32 - I think (not sure on the part #)

Stric9 wrote:My D20E's are 14mm plugs.

ARF32 - I think (not sure on the part #)

ok cool thanks guys!! STRIC9, how much horsepower did your engine make?

pigs521bbf wrote:
ok cool thanks guys!! STRIC9, how much horsepower did your engine make?

I honestly can't say. Street raced back in the early-80's (the last time it ran) and it was fast. So much so that I kept it. Finally broke it back out and down about a month ago. Managed to beg a retired machinist that used to work for Holman Moody to do the block & head work. The plan is to build a mild-medium 521 (nothing flashy) '70-1 ranchero beater. Just something to haul a bike around with and occasionally do a few donuts. I'll dyno it just out of curiosity but mainly wanting the sound and feel of that old girl once again.

What kind of plans do you have? Sounds like you may have something big planned?!

D20E's were IMHO the best street heads you could get back then.

Comp ratio and rpm?

Stric9 wrote:

pigs521bbf wrote:
ok cool thanks guys!! STRIC9, how much horsepower did your engine make?

I honestly can't say. Street raced back in the early-80's (the last time it ran) and it was fast. So much so that I kept it. Finally broke it back out and down about a month ago. Managed to beg a retired machinist that used to work for Holman Moody to do the block & head work. The plan is to build a mild-medium 521 (nothing flashy) '70-1 ranchero beater. Just something to haul a bike around with and occasionally do a few donuts. I'll dyno it just out of curiosity but mainly wanting the sound and feel of that old girl once again.

What kind of plans do you have? Sounds like you may have something big planned?!

D20E's were IMHO the best street heads you could get back then.

i am building a 521 ci big block.. the class rules are it needs to be cast iron head.. so i found some PI heads which have been ported. i am hoping to get 650 to 700 hp.. but we will see..

pigs521bbf wrote:
i am building a 521 ci big block.. the class rules are it needs to be cast iron head.. so i found some PI heads which have been ported.  i am hoping to get 650 to 700 hp.. but we will see..

Class rules - sounds like maybe a mud truck application?
Good luck with that beast! Please keep us posted on the progress.

With a flat top piston....I used AR-133 plugs on my iron headed engines.