PRC 2.5 5.3 vs PRC 215 heads.
07-12-2014, 10:45 PM
#42
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I'm leaning more towards the 215s. According to TSPs website the 215s flow the same as the 227s up to .300 lift and 10 cfm more at .400. Only at .500 and above do the 227s out flow the 215s and not my very much. So that leads me to belive the 215s would be much responsive and make for an over all more fun car.
07-13-2014, 12:00 AM
#43
I'm leaning more towards the 215s. According to TSPs website the 215s flow the same as the 227s up to .300 lift and 10 cfm more at .400. Only at .500 and above do the 227s out flow the 215s and not my very much. So that leads me to belive the 215s would be much responsive and make for an over all more fun car.
Last edited by Always2Slow; 07-13-2014 at 12:13 AM.
07-13-2014, 05:38 AM
#44
That's not how cylinder heads work. The 227s are a better head because the flow at .400 and .500 is more beneficial to you vs the low numbers. The difference in cross sectional area is minimal at best. With cams having lifts of .600 even with mild lobes you can take full advantage of the flow. Look at ported ls6 castings that are all 225 to 230cc and dyno charts. To me torque doesn't seem to be hurting when you know torque is going to peak between 4400 to 5000. Responsiveness has to do more with the cam and compression than it does cylinder head volume. Many people put huge cams in their cars and blame an assortment of parts on why their combo isn't responsive or lacks torque. The increase in intake valve size is a nice bonus with the 227 head as well.
07-13-2014, 02:06 PM
#45
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That's not how cylinder heads work. The 227s are a better head because the flow at .400 and .500 is more beneficial to you vs the low numbers. The difference in cross sectional area is minimal at best. With cams having lifts of .600 even with mild lobes you can take full advantage of the flow. Look at ported ls6 castings that are all 225 to 230cc and dyno charts. To me torque doesn't seem to be hurting when you know torque is going to peak between 4400 to 5000. Responsiveness has to do more with the cam and compression than it does cylinder head volume. Many people put huge cams in their cars and blame an assortment of parts on why their combo isn't responsive or lacks torque. The increase in intake valve size is a nice bonus with the 227 head as well.
07-13-2014, 02:53 PM
#46
Wow I always thought a head with a smaller port that flows as much as a larger port would lead to better throttle response due to the higher air velocity. If that is the case I may as well consider the AFR 230 heads also as they are available with a 62cc combustion chamber to.
07-13-2014, 03:04 PM
#47
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What your not getting with the AFR head is a reduced valve angle which trickflow and PRC give you. The key word you just said was "as much". The larger head has picked up flow in many areas over the small head leading to an increase in velocity. Looking at both the flow numbers for the 230 head and the 210 head you are picking up 10cfm at .400 and then about 20cfm after that. Depending on your goals and with the proper cam selection modified for the larger runners, the 230 is a better head. From a value standpoint of sheer dollars to performance though you would be hard pressed to beat an as cast head variant from other manufacturers. Even TEA stg 2 ls6 program is 229cc. I wouldn't really judge a head based on cc's though as its not often telling of how a head can perform. What matters is cross sectional area and port shape.
07-13-2014, 03:23 PM
#48
Gives airflow a better shot at the valve assuming the port was raised with it. You can look at the revisions with the v2 AFR heads and see one of the things they did was raise the port roof the on the new designs. With trickflow and PRC late to the game when it comes to offerings or first to market I would assume they came out with a raised roof if not its easy grinder fix. The extra PTV is nice benefit to get that responsiveness your looking with the roller over angle because you can mill the heads more.
07-15-2014, 09:15 AM
#49
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I do actually believe the 10 percent isn't 100 percent but the car did trap 126 at 1800 feet with not much weight reduction T56 430 gears. And in all honesty I hope the 490 isn't right that way it'll pick up more from the 408. The FAST was ported, 1 7/8 headers, 4" exhaust, 4" intake tract. And for comparison the dyno it made 445.8 on my Torquer 2/bolt on car made 347 on so the 10 percent is close. That car trapped 112-115 @ close to 3000 feet.
07-18-2014, 11:55 AM
#51
What your not getting with the AFR head is a reduced valve angle which trickflow and PRC give you. The key word you just said was "as much". The larger head has picked up flow in many areas over the small head leading to an increase in velocity. Looking at both the flow numbers for the 230 head and the 210 head you are picking up 10cfm at .400 and then about 20cfm after that. Depending on your goals and with the proper cam selection modified for the larger runners, the 230 is a better head. From a value standpoint of sheer dollars to performance though you would be hard pressed to beat an as cast head variant from other manufacturers. Even TEA stg 2 ls6 program is 229cc. I wouldn't really judge a head based on cc's though as its not often telling of how a head can perform. What matters is cross sectional area and port shape.
