Karl, my current motor is is a low compression motor with the head shaved about 0.040. No interference issues, but I was a bit dissapointed when it went on the rollers - 131 to 133 HP and 135-136 TQ. My previous motor with high comp. pistons, and no head shaving (9.8 compression with the Turbo head gasket at post race inspection last year) made 137 HP, 141TQ on the same dyno, though one year earlier. My current car runs a generic "turbo" muffler that may cost me HP, though. I'll have to try it on a dyno and see what it does with and w/o the muffler. Last years motor was a home rebuild by a good mechanic, this year's motor was a "pro" built motor. I'm sure you'll do better, though.

I will say that the dyno seemed to be more pessimistic this year. Bill Comat's motor that made 139/141 last year, made the same with a header & chip (that made about 4 HP more on back to back sessions at MantisSport a month before).

Karl.
The 944 NA motor is already an interferece design. So the only time the valves will hit is when the t-belt brakes or you rev it to 10k+ by getting the wrong gear on the a downshift.


Eric,
that 4 hp is reather interesting.

Consider this.

last year Comat made 139 hp. This year after back to back dyno at 4+ hp due to mods... Still 139 hp. So consider the dyno was 4 hp high last year.

So that 139 comes to 135 which is right in line with most motors. My low comp motor made 131 hp on dyno back in 2003 and then 134 hp on another dyno in 2005.

I really think the upper 130's were a bit optimistic with more cars down near 130-135 hp.

Also if you really want to see the real hp differecnce try to plot the curves. I have seen peak hp numbers not really tell the story in how a motor performs.