I have searched and still confused. I understand when swapping ONLY rockers you can be limited on the ratio depending on other components. However, when building a motor from scratch and pretty much any cam is still an option (as well custom grinds)does it matter what rocker ratio you run? does a roller cam make a difference over flat? Do you pick a cam then the rocker ratio that runs with it? or? or? or? Im stuck in this infinite loop of questions hahaha
You can manipulate valve lifts with different ratio rockers. Stock rocker ratio was 1.55 for the 70 and up 455. Early rockers were 1.59 (67-69). If you use roller rockers, TA offers 1.55, 1.60, and 1.65 ratios. If you want to increase lift beyond what the cam supplies, you can use the 1.65. The cam card lists lobe lift, just multiply by the rocker ratio to get the lift at the valve. I use 1.60 roller rockers. I'm thinking that is what most use. It isn't that big a deal. Roller cams can offer better performance and more reliability, but they cost more mainly because of the lifters. A roller lifter can follow a more aggressive profile to accelerate the valve faster. http://www.superchevy.com/how-to/pr...t-tappet-cams-which-is-better-for-your-chevy/
Depending on head and pushrod diameter on our heads you might run into pushrod hitting the heads with 1.65 I ran then on iron heads but had to have the pushrod hole enlarged for clearance.....you can go with smaller diameter pushrod provided the will hold up to spring pressure.......sometimes you can get extra thick wall to help the strength of thinner pushrods. The only reason I have 1.65 was I got a smoking deal on them
