That Hemi would be sweet.
Getting above around 450 HP will require you to modify the oil galleys. As always you should blend your oil pump and your rear main cap. The Melling 72HV ,preferred pump for hopped up LA, does not quite match up with the main's oil feed. Get the oil pressure releif spring for the pump also.
More tricks are going 1 size up on your oil lines and a oil galley crossover line in your lifter valley.
Building a large displacement LA or Magnum is alot easier with all the 4.00" stroker cranks out there. If you are going above 425hp, you should look for a forged crank. Use of I or H beam 6.123" rods is recommended for a happy engine life when it lives with 425+ hp.
As always, a good set of heads is required. There is a set of iron heads that seem to be a great product for the money. It will be harder to obtain good numbers with stock open chamber heads, so check out what Hughes has.
http://www.hughesengines.com/general/techArticleDetail.asp?articleID=1000042You will need to get your fluids moving better for sure. The oil mods above along with an electric fuel pump( I don't know of a mechanical unit that will support high hp) and a good radiator/higher volume water pump (bigger engines create more heat).
An even cheaper route would be a stock build up with the addition of a cast 4.00" crank, KB hypereutectic pistons, 2.02 heads with a bowl blend, and Eddy Torker II intake. $400 cast crank, $200 for KB 10:1 pistons, $$$ for valve job, bowl blend, and upsize valves. Get second hand internet intake and your in buisness with a whole lot more power.
BTW, 400 HP is alot of power and this engine could easily do it with mostly stock parts AND probably have the world renowned LA longevity and reliability.
