Realistic valvetrain expectations.

Pascamp said

If my current lead on a 400 comes together I may be doing my first big block build. What are the limitations of the big block valvetrain in a high end street/strip build? If I do this trick flow heads will definitely be used. The flow numbers seem fairly close to stock LS (square port) heads, and I intend to keep it stock stroke (so c.i. will be similar). I know that 1.5hp per c.i. is no problem on the LS platform in the low to mid 6,000rpm range(and done with a reasonably friendly cam). I have never seen any dynos of Chrysler big blocks performing like this. How heavy is the BBM valvetrain...is it a volume/velocity issue...other? Is 1.5hp/ci even possible at reasonable rpms without a Himalayan cam?

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1.5 hp/ci isn't practical for a street driven BB Mopar. You can easily make 600 hp with a 400 inch BB Mopar, but it won't be daily driver friendly. If you want an LS then buy an LS engine. If you want a 400 inch BB Mopar then accept the limitations. There is no magic button that you can push that turns a BB Mopar engine into a LS engine. If you want a low deck engine that is reliable but powerful then I'd recommend building a 470 with Trick Flow 240 heads, a hyd roller cam, 10:1 compression, small headers (1 3/4 inch TTI most likely) and a Holley Sniper setup complete with Hyperspark ignition. That is a fairly simple combo that most engine shops can screw together and it will make gobs of torque and power. If you pick the cam wisely the engine will be smooth at idle but will put out enough power to put a 2700 lb car into the 10's.