[Synchro909]

IMO, Larger inlet valves are not needed in Terry's new engine. Being new, the valve seats have not had a chance to recede into the block so gas flow is better than an old block there. The inlet tract has also been improved (the change cannot be seen from outside) which again, improves gas flow.
I had everything ready to go with larger inlets but changed my mind. I was not looking for a racing engine, rather something with more stamina for towing. Flexibility is important so I backed off on the valves. I run a 6:1 cast iron head, Webber carburettor, a modified B grind on the cam. (0.308" lift) and an original distributor. To limit the advance (to 22°), I made a bracket which I screwed to the side of the distributor. It has a screw in it that stops the top plate at 22° like an idle stop on the carburettor with no sponginess like I would expect from putting a clamp on the lever quadrant. I rune the lever in one of two positions - "town" and "country". ie, part advance or full advance. I am very happy with the result. I get better fuel economy at 85 kph than at 75. (53 vs 47 mph) Given these cars are as streamlined as a house brick, the drag at 85 is much greater than at 75, yet the economy is better. About 22 mp(US)galon vs about 20. I figure that is about the speed where cam, compression and carburettor all come together to work properly. It is easy to overdo things in there. I decided to go with standard valves partly because I could see that larger valves wouldn't give much benefit because they would be shielded to a greater degree than standard ones. Besides, it would have affected warranty and the hardened seat were already fitted.
We run 91 octane non ethanol fuel.