Anyone??how Much Do You Really Pick Up With Heads??
Depends on the heads, but with good ones, you'll pick up at least 50 rwhp over cam only. Some have hit or exceeded 500 rwhp with stock displacement 346s and hydraulic cams the size of the T-Rex.
So if the heads flowed lets say, 300cfm that would be about a 50hp gain??
If they flowed 300 cfm at .600 or less would help, but you need really good flow at .300-.400 too. Reason why? The piston has its highest speed and strongest draw to the intake port around the point that valves are in the .300-.400" lift range. Once the valve is at full lift, the piston has slowed down some. On a 3.900 bore and 28" of H2O, you want over 200 cfm at .300, and 245 or better at .400, 280 cfm or better at .500. Meet or exceed those numbers and 50+ rwhp from heads is in the bag with the correct tuning and supporting mods.
AFR225s and T-Rex. Should rock. I know the AFR205s pick up about 40-45rwhp and most of the ported stock heads do around the same. 50rwhp over the 853 LS1 heads sure, but over the 241 or 243, it's a little less.
The 225s should be good for another 20rwhp over the 205s, and from what I've seen, that is true. So, look for 60-70rwhp increase with the 225s.
The 225s should be good for another 20rwhp over the 205s, and from what I've seen, that is true. So, look for 60-70rwhp increase with the 225s.
