253checkmate

I Am Running A Gen 6 454 Mag. Carb Engine With A 5 Psi Procharger And Was Looking Into Upgrading The Heads And Possibly The Cam. The Engine Has Cyclone Headers, Single Plane Intake, Msd, And Stock Internals At This Time. The Engine Has Good Compression And Runs Well. I Was Looking At Some Afr Heads But I Am Not Sure What Would Work Best With The Procharger. Thanks.

articfriends

iTrader: (1)

I switched from out of the box merlin vr heads with a slightly improved valve job and better springs to afr cnc 315's. I made 150 plus hp more with the afr's that I did with the merlins. I also did some small improvements at same time (ideal optimized custom ground hydraulic roller from rm builder).The thing you and everyone else need to keep in mind is a blower motor forces the intake charge into the cylinder. A mediocre intake port can have air forced into it like a good flowing cyl head port but the exhaust port is still just exhausting gas in the same manner as a n/a motor plus very little scavenging help from the water cooled exhaust. Thats where a cylinder head with killer exhaust ports and as least restrictive exhaust as possible will give you the best hp.Afr wanted me to run their 357 cc intake port heads when I called them and asked when building my procharged 540 but their own cyl head flow data said the opposite. On AFR'S (and most other aftermarket heads) they use the same exact exhaust port with different flowing intake ports. I chose the 315's against their advice because I wanted good idle and midrange plus unless you jump up to a big solid roller you would never see the 700 plus lift it took to have any gain from the higher flow the heads had on intake side. The exhaust numbers were the same between most their heads and blower is going to force the air thru the intake port anyways. It worked out real well for me,Smitty

253checkmate

Thanks Smitty. Do You Think The 315 Heads Will Be Ok For My 454? I Do Plan On New 502 Or 540 Short Block In A Season Or 2 But I Want The Inconel Valves For The Reliability Factor Now.a New Long Block Is Not In The Budget Now And The 454 Is Still Running Great. Thanks. Chris

HPJunkie

253, I think smittys right on with those heads, definatly no more than 325cc. A friend of mine runs nitrous cars with 540's in them and usually run the 345-355 range. one car has some "leftover " 315cc brodix heads on it and he reports that the torque is just awesome on the street vs the bigger headed motors. (no nitrous) I have ported 315 brodix heads on a 502 and it runs great. Id consider the AFR's next time if I buy...the write ups and numbers are always good. In that boat you probably wont need inconel although if you have the heads built for you (which I would do ) then get them. THe reason I say that is you wont be holding it WOT that long and building that much heat like a 40' boat going for 30 minutes at 5500 rpm at 70 mph. You'll be white knuckling at 85 or so. I bought assembled head. I had to disgard the springs anyway to put ones on that matched the cam so that was money wasted. Get the CNC bare head order your valves and springs to match the cam and have your machinist put them together. Its easier than you think probably 2-300 more but much better.