Autocross Motor Advise

[lpope]

How much horespower do I need in my 66 Nova. Car will get more time on the street but will need to performe well at local autoross events when needed. I have a Detroit speed tubs, 4-link, and front clip installed. I was thinking about going with the RHS block (454) natuarally asperated and using the T56 magnum. I have been told that the 454 can easiy produce 700hp and still be a joy to drive on the street. What are your thoughts and recommendations for a Ls builder who has experiance with autocross/road race, seems most serious builders concentrate on drag.