Marcello, even though the Distributor is topside, it is gear driven off the end of the camshaft as was the older versions. The length of the newer pulley/fan assembly is almost identical to the older because it had to clear the big double capped distributer. If you have the original fan generator set up for the 49-53, you should be able to fit it in with no problem. If you don't have the bracket, gen. and pulley, then you will need to go after market. Let me know if you don't have what you need and I may be able to help you out. Years ago, this was a common engine swap because of the improved distributor location and additional 15 to 25 HP gain.