I would have to disagree with John on the crank pulley. The rest of the pullies are a waste of money. The underdrive pulley on a 420a is different then a 4g63t. Its not a harmonic balancer. On a NA 420a you get more gains from the UDP then you would from most or any other mods. The aftermarket UDP is smaller then the stock 420a crank pulley and will require different size belts. If you choose to... Howell Automotive sells the AF/X UDP pulley which comes with the belts. This pulley is recommended by many. As of last week mines being machined, they ran out, should be here soon.

If you don't believe me then you can research it on 2GNT.com