It’s not just the LSA. The cam you have is not suited for a low rpm small cube big block with a single plane intake and exhaust manifolds. The @050 duration wants that engine to be spinning 3500-7000 and 11:1 compression to be optimal. You need a large step backwards. That cam was originally cut by Howard’s cams and my opinion is you should contact them and see if they’ll cut you a more appropriate cam for your combo on the same base circle. Then MAYBE your pushrod length and geometry might work out. But it does not excuse you from measuring and checking.
