Need some help from someone smarter then I am Let me start off I am a reformed chevy guy always liked mopars so I made the switch.The car Im currently trying to complete is a 70 duster thats been backhalfed for a 14x32 tire hopeing traction wont be an issue.Has 4.88 gears and a 8 inch converter that will flach in area of 5200rpm.Dicided I would use what I had so I took a 383 block added 440 crank for 432 ci did all needed mods decked so piston are .005 in the hole for proper quench etc and was going to deck heads to get to 12.5 1 compression never giving a thought to exh valve to cyl clearance 4.280 bore is big compared to what im used to but lol and behold I got bit. I cut eybrows in cylinder to gain clearance for cam ultradyne 277@.050 .640 lift 108 installed 103.5 piston to valve clearance is not an issue but I dont think it will work well with 10-1 compression. I believe I have enough clearance to mill head .050 hopefully get it to 11.5-1 but still think this cam is to big Any ideas on a better cam Im thinking something in the 250-260 duration or do you think this might work reasonbnly well going to be running e85 if that makes a difference sorry to be so wordy just wanted to give as much info as I could.Also how much clearance is needed valve to cyl.Thank you