Here is what I'm working on. 9.8 mark IV block 4.310 bore, 4.375 stroke, 6.385 rods for a total of 511in³. Aluminum 118cc combustion chambers, -18cc dome pistons.
What I want to go with is Howard's 120325-10. Hydraulic roller 229°/235° @ .050. .589/.600. 110LSA
I am worried about two things. Here are my pistons.
They have a huge intake valve relief for the intake valves and nothing for the exhaust. Will I have to worry? The exhaust does have .011 more lift. I don't know of a way to check this before I order the cam.
I am also worried about detonation on pump gas. The static compression is 10.48:1. I realize elevation makes a huge difference. I am at 600'. Howard's emailed me the cam card. The intake closes at 67° ABDC. That will put my dynamic compression at 8.18:1. Do I need to worry about detonation here?
I'd like to advance the cam 4°. That puts my dynamic to 8.44:1. Is that in the danger zone with aluminum heads and 93 octane? Does advancing the cam help or hurt piston to valve clearance?
What I want to go with is Howard's 120325-10. Hydraulic roller 229°/235° @ .050. .589/.600. 110LSA
I am worried about two things. Here are my pistons.
They have a huge intake valve relief for the intake valves and nothing for the exhaust. Will I have to worry? The exhaust does have .011 more lift. I don't know of a way to check this before I order the cam.
I am also worried about detonation on pump gas. The static compression is 10.48:1. I realize elevation makes a huge difference. I am at 600'. Howard's emailed me the cam card. The intake closes at 67° ABDC. That will put my dynamic compression at 8.18:1. Do I need to worry about detonation here?
I'd like to advance the cam 4°. That puts my dynamic to 8.44:1. Is that in the danger zone with aluminum heads and 93 octane? Does advancing the cam help or hurt piston to valve clearance?