aftermarket double roller set does not mean anything--where the timing is what matters-what are the manufacture and part number of the set and any pics of it?
Have you got rid of the cats? Do you have adjustable valves? or just the oem solid bolt downs? If so , there are bearing centers you can use but will still need to have correct pushrod length. put an ign retard system in it so you can pull the timing back in high gear on the quarter mile and use around 40* total and retard it 3, 4 degrees when shifting into high.

best gas you can get-----