400's are they any good?

sounds like 451 maybe the limits of the block from what I gather, and that would be with a stroker kit

Incorect. Actual cubic inch max is limited by the 2 factors of it's max bore and max stroke the block can handle from the crank.

A 498/500 cube engine is easy and cost little in difference over a 451.

if don't skroke it out it won't go that fast.because of the low compression it has. they are only good for if u stroke it out.

As said several times before, the 400 just lacks compresion and then a decent head on top....shold the stock head not be enuff with or without it's stock valves and in a fully ported condition.

In order to get a high compresion engine, you need not have to stroke it. A new set of pistons is all it takes.