^^^ Yeah I know - you are one of only 3people outside the US and Australia that undersdtand let alone appreciate the push-rod..
I was refering to the fact that all the super high performance OHC super car engines have really strict and expensive maintenance requiremnts as well, so it's almost a result of the performance level of the engines, not just the design..
NOt to mention the 20,000 mile annual valvle spring renewal on a Chevy is going to cost 1/4056th of the cost of the same job on a Lambo..