I've heard of cars running 350whp on stock internals from some pretty reliable sources (past posts by Shiv from Vishnu and some other folks in the business). Are the stock internals reliable in the 350whp+ range? Hell no, but I do not think you care too much about that. Will the internals hold at 375whp+, probably not for long, but with enough fuel and you might get some very decent quarter runs in it. The white car mentioned above is probably the most I've ever heard of on stock internals...was owned by a guy in CA if memory serves. The crank is strong, but not sure how long the bearings and conrods will last under that kind of strain. Would be interesting to hear what you have in mind.