400 big block + my 71 Demon

With Schumacher headers on an RB motor, access is tight on the passenger side - but the plugs are still accessible - no need to beat or cut anything. The deck height on a B motor is 3/4" less so access should be slightly better - at least with those headers.

Unless you're racing where every 10th counts, don't discount the Schumacher headers because they're not full length. Read this article and before weighing the pros and cons: http://www.engine-swaps.com/Pages/ArticlePages/SmokinBarracuda.html