Quote:
Originally Posted by Blue Rat
Velocity is more important when it comes to head flow numbers. If you do the 461 go with the 270cc heads. If you go with the 489 I would go with 270cc to 300cc heads. I would stay with oval port for better flow if it was me. The solid roller would make some good numbers. But it has to be right on the camshaft. You also need a lot better parts combo too. Need better valves. Be sure a pick some pressure fed lifters. Your valve spring pressure is going to be a lot higher too. Head Studs an good rocker arms an push rods are a must with a solid roller. Don't forget about the stud girdle.
Don't forget about those expensive head gaskets with aluminum heads.
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Velocity and flow numbers have a equal importance. Velocity give the low mid range power and part throttle response. Flow numbers will tell you how much HP you can make. Agree with the head sizes though. Dont see how head studs are required for a solid roller cam but they cant hurt. Morel lifters are about the best roller lifter available but your going to pay for the quality. Using the right parts this can easily turn into a $10k engine.
You need to set a budget and stick with it and build within those means. You can get balanced rotating assemblys for $1800-$2000, block machine work can run $400-$1000 depending on what all is done. Rebuilding stock heads will run you $700-$1000 WITHOUT any portwork. Add about $1500 for a good port job. Add $1500-$2000 for roller cam, lifters, springs and pushrods. Then add in for roller rockers, gaskets, intake manifold, carb, ignition, engine hardware, oil pump and pan, it all adds up.
What I would do is concentrate on low-mid speed torque instead of HP. You can get close to 600ftlbs pretty easy if not more and still be in the 550-600hp range.
There was a build on another forum with a 9:1 489, out of the box brodix oval port race rites and a standard performer intake and the straub cam I linked to and it made 580ftlbs and 530ish hp. Better intake and more compression would get it a bit higher. The torque is more than enough to push a heavy truck around.