Any difference between MY '66 and '67 911 (normal) engines?

[911E4ME]

Hi there,

I'm about to buy a '66 911 (Produced in May '66...came with Webers orignally) that has had its engine replaced with that from a '67 Normal (non S) 911. Are there any differences in these two engines with regards to power or part improvements?

Thanks

[304065]

Well let's see here

Cam profile of the 901/05 (66) vs the 901/07 (67) is different- the 67 motor had softer cams to reduce the power. In 1967 when the S came out with "SSI" type exhaust, there was also a comprehensive recall of the early heat exchangers by Porsche. The early heat exchangers had a weld seam inside the hot air clamshell: this would rust and potentially leak CO into the cockpit. Hence, Porsche replaced the HE.

When the HE was replaced the power output of the 901/05 went to 140BHP. This was considered too close to the "S" output of 160, hence restrictor rings were installed in the exhaust to lower the power level. Then the next year (67) the cams were changed.

The other improvement is that the factory used longer rocker shafts with a larger pinch bolt.

Other than that (and small differences like fastener plating) they should be identical.