road car cam for my 318

RustyRatRod said

My opinion is you will never in a million years feel the difference between a 112 LSA and a 108 LSA in such a mild build. However, the 112 LSA will have a better vacuum signal and operate vacuum accessories such as power brakes better than the 108 LSA all things equal. It's just not a decision I would dwell on for two minutes. I'd have one on the way already.

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It is the overlap the defines vacuum. A 112 LSA with X degrees of overlap will have as much vacuum as a 108 LSA with the same overlap. If you read Vizards books he has data that shows what LSA (all other things equal) can do if you get it wrong. The difference between a motor that wants low LSA (because it does not have great heads and small valve diameter) and going to a long LSA (108 to 112 is a huge difference he did 108, 110 and 112 I believe) was over 20HP and 20 ft-lbs of torque. His data has shown that the highest sensitivity to optimal engine operation is LSA selection not valve opening events (remember the other key here is keeping overlap similar as that is what you select to decide where you want the power band). He is in the middle of this debate on his YouTube channel right now as Eric Weingardner is doing a cam shootout on his channel this week. Entrants design a cam for specific mule engine he has. Will be interesting.