Hi Folks,
I'm having slight problems in planning my engine project. I have a 5000 lbs vehicle with a 350 SBC, bored .060 over, so it's a 360. I took it apart because the chap who built it screwed everything up, put on bent and cracked heads and so on... The block is a good 4 bolt, bores are still clean because the engine didn't run long enough to even establish any sort of ridge at all. I want an engine that will deliver good mpg and have nice bottom end torque and a smooth idle, but with more power than stock. Enough blabla, here is my problem:
I read that...
... you should aim for the highest CR possible without domed pistons, because that will increase the efficiency of the engine (more mpg, better combustion)
... short duration cam with tight LCA and little overlap if you have a heavy vehicle, want bottom end torque and a smooth idle
... go for tight squish by zero-decking the block or using thinner gaskets if the engine is perfectly flat
... use a low lift cam and high lift rockers to get good lift (to get more mixture into the cylinder in the restricted time a short cam opens the valves
Surely the first and second statements contradict each other, as I.M.O a high CR needs a longer cam to work without detonation, because the dynamic CR will have to drop (which a longer cam does) to eliminate detonation.
So what CR and cam duration should I aim for? I'm planning to get good heads (Dart, World, 041, 186, that style) with good swirl, so I need to go for tight squish to make the most of them. I computed that with 64cc heads and zero deck I could top 10.5:1 static CR even on pump gas, which is better here in Germany (about 96 or more octane). But then i need a longer cam than I want. I've checked out Comp and Crane and got basically two different opinions: either long cam, high CR or short cam, low CR. Isn't short cam, high CR going to work? What will that give me? How would the engine respond to that combination? Would really like to here as many different opinions as I can get. Or where am I going wrong here? Thanks again for all your help,
Mad