66 vs. 67S Engine

[50/50]

I am looking to upgrade a 66 to 67S or higher specs. What are the differences in components: carbs ,cams, valves,P+C's, ignition, crank, rods, etc? Checking to see if it is more cost effective to locate a complete engine.
Thanks,
50/50

[Fritter]

Main differences are

Cams
Heads/Valves
Pistons

The carbs and disty are also a bit tweaked. And I believe some of the internal engine components (crank, rods) were checked more for flaws and perhaps treated in some way to strengthen them.

Probably more effective to find the parts and convert your existing engine. Buying an entire S engine is pricey.

[50/50]

Is the crank the same (counter weighted)? What are the valve sizes? Also the carb bores?

[John Fusco]

Valves: 42/38
Lift: 11.6/10.3 ( 11.55/10.57 - 901/05)

Light alloy forged pistons instead of cast - nitrided rods.
Little end bushes solid copper alloy instead of rolled bronze

Venturis were 34s

Then on to the brakes and sway bars, gear ratio...

[50/50]

Thanks John
What are the differences with the crankshaft?

[John Fusco]

Not aware of any difference. Both were counter-weighted.

The crank on the T and the 912 were not - but interestingly the heads on the T were the same as on the S.

[preS]

Not aware of any difference. Both were counter-weighted.

The crank on the T and the 912 were not - but interestingly the heads on the T were the same as on the S.

912? The 912 did have a counterweight crank (too) but is of course 4 cyl.

Richard

[John Fusco]

I stand corrected.
Thanks Richard.

[Fritter]

Yes, the crank is counterweighted. The differences are spelled out very nicely in Paul Frere's book.