A 406 is a very common build, it is a 400 bored over with a ton of options. I believe it was John Lingenfelter (could be wrong) who built the "first" one in the '80's & they took off from there. The early ones used 350 rods (longer) with custom pistons. Today it is still a common way to go but the options are endless. Scat and others now have stroker kits to bring it to a 427 and 434.
Punch in 406 Chev small block in your search engine & research it. It is easy to get over 400hp and over 400 torque & still run pump gas.
I know of 3 406 builds in my area. I'm running one in my '86 Monte Carlo SS & expect a low 13 in the quarter on regular pump gas. The factory 400 has 5.5" rods, a 350 has 5.75" rods which where the most common way to go till recently when the 6" rods became available. It is easy to push over 400hp with over 400 torque reliably on pump gas on a proper modern 406 combination.
Here are a few documented builds including parts list
I'd say go for it & enjoy