Have a 68 vert with th400, 3.08 posi with a nice hole in the 400 block thanks to nephew. It has 96 heads, edelbrock performer intake, headers, and Holley I can reuse.
Would I be better of performance and cost wise to go with a 455 short block and keep my stuff or get a 400 long block with some ported 6x heads and keep intake and carb? I like the idea of keeping the car with a 400, but if the price and performance with the 455 short block is much better I'm good with that too.
It will be a cruiser and not see the strip, but pushing 400hp and 450tq would be nice to shut those 5.0 d-bags up.
What year 96 heads are on the 400? A 400 or 455 will be similar in cost to build, the 455 will provide more torque for the money. I would spring for forged rods, factory rods are not the best, but using ARP rod bolts will help. A set of 6X-4 heads on a 455 would put you in the low 9's compression-wise, perfect for pump gas. Many use a RA IV cam in a 455 with great success. My.02...