Are you going to be running nitrous?
Oval port Intakes are not great on nitrous engines. Before I get corrected let me explain. One of the top nitrous head suppliers to the industry is CFI Carl Foltz. CFI last year went back to the rectangular ports with radiused corners for their nitrous heads only.
If this were a street engine I would go for the 496.
If this is an index or bracket engine I would say go for the 496.
You did not tell us the cylinder head options if you go with the 496.
Ed