Why did nhra change the cam and valve spring rule in 1985?

art leong · 07-02-2010, 08:12 AM

I believe they changed the cam and valve spring rules. For 2 reasons
1 The GM guys were constantly crying because Mopar wrote "bogus" numbers for thier cams. On our Hemi car if we put as much duration and overlap as we were allowed it never would have been able to start.
2 Is they just got lazy not wanting to have to calibrate testors and measure the spring heights.

Back in the day. We would go through aload of used "battleship" outer springs to get 16 that would check legal. I think we were allowed 180 on the seat 320 wide open (these numbers are from my memory which isn't always right)

07-02-2010, 08:12 AM	#5
art leong VIP Member Join Date: Dec 2001 Location: Richmond Hill, Georgia Posts: 2,003 Likes: 0 Liked 1 Time in 1 Post	Re: Why did nhra change the cam and valve spring rule in 1985? I believe they changed the cam and valve spring rules. For 2 reasons 1 The GM guys were constantly crying because Mopar wrote "bogus" numbers for thier cams. On our Hemi car if we put as much duration and overlap as we were allowed it never would have been able to start. 2 Is they just got lazy not wanting to have to calibrate testors and measure the spring heights. Back in the day. We would go through aload of used "battleship" outer springs to get 16 that would check legal. I think we were allowed 180 on the seat 320 wide open (these numbers are from my memory which isn't always right) __________________ Art Leong 2095 SS Last edited by art leong; 07-02-2010 at 08:16 AM.