There's no replacement for displacement, this holds true on the old FE's, too... Barry at Survival Motorsports is an FE guru, you name the combination and the budget and he'll tell you what works and doesn't work!

From personal experience with the FE's, they need good breathing heads!!!! There are a lot of peculiarities on an FE, first concern is it an FE or an FT? If it's the original engine in the pickup it would be an FT. Scooting mentioned building a 410 ci version, had one in a '68 pickup with a set of out-of-the-box-stock Edelbrock Performer RPM heads, intake, cam, and lifters topped by a 750 Edelbrock carb..... It ran great by itself and was never low on power when it was used as a tow rig! If the occasion would arise again to build an FE, I'd go with one of Barry's stroker kits and whatever he recommended for heads, cam, and valve train.

Be realistic on your build, make sure your budget will cover your expectations!!!!