308, 7X engine

blondwookie

I am thinking about building a 7x engine. I spoke with 21st century Hudson about this, i can install the new 7X valves into my engine, once the machine work is done. My questions is simple, 21st Century Hudson said that my head, cast number 309121 will work fine with what I'm planning to do. Is the a 7X head that will work on my 55, 308 engine?

Glowplug

Go to my website and there is information on the original 7X head including pictures.  Today these engines are equipped with a variety of heads including the crate engine heads.

blondwookie

thanks for that

54coupe

I suggest using the head you have. The 7x head was a 232 head, which had smaller combustion chambers than what you have. It will be great for a few months on 91 octane pump gas. When you get a little carbon buildup it will start to ping under a load, so you will back the timing off a little bit. That will work for a short time, then you will do it all again. By then you’ve lost all the power that the extra compression gave you, and you will put a 308 or 262 head back on it. You may see a difference at the track with the 232 head, but your butt cheek dyno will never know

blondwookie

thanks, I'll do the old school trick of blowing out the carbon at highway speeds, along with some minor road racing.

Ol racer

FYI

I believe the 7x 232 head combustion chambers were slightly different than the regular production 232 head to prevent detonation. I think former drag racer Rudy Bennett had pictures on the old Forum with the differences....

Glowplug

Chuck is correct and Rudy provided this information which is posted on my website in the Engine section