When John Trease here in Australia built the Engine for Ian Boyd's Vinton racer, he used rockers with a 1.6:1 ratio, the cams only had about 340 lift at the lobe, but a different story at the valve of course. The ratio change loaded the cams and followers so much that they failed rather quickly. So he did away with standard cams/ followers and went to a solid lifter design, a full oil pressure oil pump, three piece crank with a custom made conrod of some horrendously expensive material from Germany. The mods he did to the cylinder head......I won't even got there, but lets just say, when I asked if he would make any others, his answer was a deafening "No way" way too time consuming. This same bike reportedly put out over 62 HP on the dyno, a figure which some disbelieve, if any of you have seen how fast Johns period 3 Harley racer is on the track. It is amazing. Most period 3 bikes at Phillip Island cover the 4.5 km circuit in 1.55 to 2.00 minutes, the top Gp riders do it in about 1.30 and best lap times of about 1.28......Johns Harley did it with Cam Donald in the saddle in 1.46.....this same bike held the lap record there 10 years ago. A record never beaten. I could be wrong, but someone told me that the new heads that Terry makes, and dating back to the original RTV/TPV heads were heavily influenced by John's design work. This also applies to the new heads for the new Series "A" twins that Neal Videan and Rodney Brown have built. Cheers and thanks for the replies so far..........Greg.