Hi, does anyone have a head blue print for a big power junior dragster? Or even a good picture of the combustion chamber? Do these things use flat top pistons, or is there a dome? I'm planning to build a non-ford flathead and going for as much power as possible. The head will be custom built, the bore will be right around 3 1/2, so I thought that maybe I could copy the combustion chamber and piston top design from these 3.5 bore engines. Since they Make almost two horsepower per cubic inch naturally aspirated. Pretty amazing for a flat head

They make that on alcohol. Around 40 hp. back then.

My son ran one back in the early 2000-2003 time frame. I built it using a purpose built cast Rhino block at 3-1/4” bore.
The piston had no dome, the chamber had valve reliefs, the area above the piston was half flat for the quench area and then sloped up about mid bore to the valve reliefs.

The area you want to work on is the area between the valve and the bore for each valve. Think a trough for each valve.

We used to spin our motor 7500-7800.

Joel, Mike has a Jr. Dragster, and a spare engine. I can ask him if the spare engine is in pieces, or together.

Joel should have no trouble making it turn into pieces if it happens to be together

He has been known for that.