AFR Heads.
#62
Thats hard to feel because the engine isnt laying down hard.....but you did in fact lose some peak power (could be 10-20 even), and the engine will certainly nose over faster with RPM.
"Valve float" is just a severe case of a loss of valve control and the engine lays down notably almost like there is some sort of rev limiter in place.....easily seen on the dyno (the curve drops off sharply) and easily felt from the drivers seat (engine feels like it hit a wall and its out of breath).
Guys....if your really looking to turn a hyd. roller hard you need to pay attention to mass. Component weight is the enemy including the valve springs and retainers themselves. Reducing the weight of the valve, the rocker arm, and the entire spring assembly pays huge dividends in performance from increases in valve control. Think about the beehive spring and how effective that is in spite of its softer seat and over the nose pressure. Now honestly a smaller lighter weight dual spring is my choice (only slightly heavier than the beehive but with more seat and open pressure) but I bring up the beehive only to make a point. The reason it works so well is because a spring has to also control its own mass....a major reduction in spring/lock/retainer weight has the same effect as running a much lighter valve and rocker assembly.
Honestly, its one of the larger benefits of the AFR Eliminator heads....8mm valves, with light weight beadlock keepers and small diameter dual spring/retainers help valve control and power output in a big way.
Regarding whether a 210 is a good choice on a 383 with a solid roller the answer is yes....a very good choice especially for more of a dual purpose car that still sees some street duty. It will have a very broad power curve and still pull reasonably well down low and be able to run right up to 7000 RPM or so upstairs quite effectively also. You could argue its the perfect head for a hot dual purpose ride but if you only roll your car out of the garage on Friday nights to go street racing with the boys, and are willing to get more aggressive with converter and RPM, a 227 solid roller combo will deliver in the HP department offering more power potential at higher RPM's, but IMO it wont be as good an overall combination as the 210 version if you care at all about low RPM torque, low speed snappiness, and part throttle tip in in high gear.
Mind you the right combination with the larger 227's will drive OK...it just wont have a whole lot going on till the tach starts swinging past 4K or so, and the "jump to lightspeed" part of the power curve would start from 5K where it will want to rip into the mid 7000's with the right set-up (perfect for a car with a manual trans or a more aggressive stall converter). Essentially we are just kind of discussing two different engine personalities more than anything else and the larger 227 head is better suited for the "meaner" more aggressive (and more single focused) high RPM power charge. One curve is peaky while the other power curve offers more area under the curve but ultimately less peak power.
Once again....the "right head choice" is more of a personal one....and in some respects there isn't really a right and wrong here.....only whats more right for your disposition, goals with the car, and the rest of the combination, but its very important you make sure the rest of the combo compliments the head you select or the package might not be especially impressive at any RPM.....as I said earlier....combination is king.
-Tony
Last edited by Tony Mamo @ AFR; 03-21-2012 at 08:47 PM.
#64
Great post Tony. When the new combo hits the dyno Ill change out the SS rockers if there is any signs of uncontrolled float.
When pick up some new heads Its going to be the 227s or similar. I dont care at all about low end TQ. When the car is on the street it either hits a car show or the street races so maybe a couple hundred street miles a year. It heads to the track on a trailer more than anything after all its got no AC, Kirkey seats, no radio, AFCOs full tubular suspension, cage etc not so much a true street car even if I like to call it that. lol.
Future goals for the car is to be in the hunt for the nitrous record.
When pick up some new heads Its going to be the 227s or similar. I dont care at all about low end TQ. When the car is on the street it either hits a car show or the street races so maybe a couple hundred street miles a year. It heads to the track on a trailer more than anything after all its got no AC, Kirkey seats, no radio, AFCOs full tubular suspension, cage etc not so much a true street car even if I like to call it that. lol.
Future goals for the car is to be in the hunt for the nitrous record.
#66
Great post Tony. When the new combo hits the dyno Ill change out the SS rockers if there is any signs of uncontrolled float.
When pick up some new heads Its going to be the 227s or similar. I dont care at all about low end TQ. When the car is on the street it either hits a car show or the street races so maybe a couple hundred street miles a year. It heads to the track on a trailer more than anything after all its got no AC, Kirkey seats, no radio, AFCOs full tubular suspension, cage etc not so much a true street car even if I like to call it that. lol.
Future goals for the car is to be in the hunt for the nitrous record.
When pick up some new heads Its going to be the 227s or similar. I dont care at all about low end TQ. When the car is on the street it either hits a car show or the street races so maybe a couple hundred street miles a year. It heads to the track on a trailer more than anything after all its got no AC, Kirkey seats, no radio, AFCOs full tubular suspension, cage etc not so much a true street car even if I like to call it that. lol.
Future goals for the car is to be in the hunt for the nitrous record.
#67