Boosted2003

I got some sdm shit shipped it should be here like 3 weeks..

stock head here:

Valves: 44-35 mm, valve seat inserts 46-38 mm.
Combustion chamber dia: 92˝mm, somewhat smaller/narrower compared to the big ones
Height: 12mm
Volume: 51.7cc i.e. 4.3cc/mm
Intake channel: Straight, conical, round, slightly less inner radius
Exhaust channel: A slight hint of a plateau after guide in channel
Casting number, best: 1000530
Other: 100160, 1000398
Potential: Correctly modifyed: Good top-hp with a very good middle-rpm. On little engine hard to beat, indeed.

My new head:

Valves: 44-35 mm, valve seat inserts 46-38 mm
Combustion chamber dia: 94mm, a slightly wider layout especially around exhaust, 531 has a little more centered spark plug location.
Height: 12mm
Volume: 53.7cc i.e. 4.5cc/mm
Intake channel: "Swanneck"-shaped, venturi A LOT larger than the small ones, flat and larger inner radius,
Exhaust channel: No hint of a plateau after guide in channel
Castingnumber, best: 1000531
Other: 100405
Potential: Correctly modifyed: Very high top-hp with a good middle-rpm, especially on big volume engines.