Well, I did another one of my patiented "brain dead" screw ups.

Last season, my engine builder gave me part number for spark plugs for the new engine. I picked them up, indexed, and installed them. Never gave them a second thought. I did pull and check them a couple times, and they looked OK.

Just last Friday, while assembling another new engine, I installed those same plugs just to see how they "indexed". To my surprise, they didn't even clear the hole. So, all last season I am running with the plugs receded into the holes. I am not an expert on this, but this had to have an adverse effect on performance.

Anyone out there have some thoughts on this. Also, could this have caused the problems I had trying to run Alcohol.

Ken Gasbarri

Sure would drop the compression! What heads?

Alky is hard enough to lite I bet you might find a slight performance increase.

I have DART 320 heads. I have talked to a number of people, and it seems that DART recommends those plugs with a .450 reach. I haven't spoke with DART myself yet, but if that is so, I will be interested to know why.

Ken Gasbarri

Draginrat,

I have had the same experience with my Dart Pro 1 heads using the wrong plug.
I was having a mid-range rpm 2000-3500rpm miss that was driving me crazy graemlins/clonk.gif
For some reason at the track after 3500rpm it didn't miss a bit (maybe the MSD ignition box helped with that).
After chaning to the correct plugs, my low end miss went away, and my times at the track did pick up maybe a full tenth.
I didn't find your particular head on the Dart website, but all the ones I checked used the same plug http://www.dartheads.com/cbbhpro1cnc.htm
Good luck

chevymetal;

I thought I had posted a reply, but somehow it didn't get there. Anyway, thanks for the link.

I checked that web site and discovered that the plugs my builder recommended were never recommended by DART.

I believe my 320 heads are a smaller (runner cc) version of the 360 heads. Doesn't seem like they offer the 320 heads any longer. I have had mine for about 5-6 years.

They (DART) recommend the .750 reach plugs for all their BBC heads, so I have no idea where Rick came up with the .460 reach plugs. I don't have access to the heads right now, but when I get them this afternoon, I have some checking to do.

Anyway, I will let you all know what I find. Hopefully, I will get this solved and maybe get a little performance boost.

Ken Gasbarri