Just my nickel, but put all the advice together to come up with a solution. The performer RPM heads don't work with the stock pistons. My suggestion would be to go with Twisted wedge heads which utilize the 2.02 intake without touching the pistons and go with an E or F cam with 1.6 Roller rockers. You will drastically increase the power range with a different cam. The stock cam with 1.72 increase your HP by about 10-15 HP but an E or F cam would give you closer to 25-40 HP over stock.
You can pick up a used cam for about $100 and the Twisted heads go for around $1000. The Roller rockers are around $150 used and you can offset the cost by selling your 1.72 and cyl. heads. Actually, you might find someone willing to trade 1.72 for 1.6. Good luck. You might want to upgrade to a 650 carb depending on which 600 you have. Tim
You can pick up a used cam for about $100 and the Twisted heads go for around $1000. The Roller rockers are around $150 used and you can offset the cost by selling your 1.72 and cyl. heads. Actually, you might find someone willing to trade 1.72 for 1.6. Good luck. You might want to upgrade to a 650 carb depending on which 600 you have. Tim
