Here are a few good reasons why we think the 427/434 engine is a better choice than the 383 or 406 engine.
The 427/434 will accelerate most medium to heavy cars dramatically quicker than the common 383's on the market. The main difference between a 427/434 and the 383 is that the 427/434 torque comes in much lower. The difference is so dramatic that you would estimate the engine to have a much higher horsepower rating than it actually has. If you're not familiar with the 427/434 engine, do an internet search on SBC 427 vs 383, and you will be convinced of the difference. There is no inherent weakness in the 427/434 engine when using a Dart high performance block.
The exhaust note produced by a 427/434 is dramatically deeper than any of the smaller cubic inch engines on the market.
A 427/434 engine can be installed in medium to heavier cars without killing acceleration, having to deepen the final gear, and needing a huge stall converter. This engine will accelerate a 3600 lb or heavier car much better than the 350 or 383.
Very low maintenance, decent drive-ability, yet costing only slightly more than building a 383 or 406 street rod engine. Horsepower will vary, depending on cam, carb and intake choice. You have up to four different cams to choose from, and two styles of intake manifolds plus two rocker ratios.
Should you ever decide to sell your car, the resale value of a street rod with a 427/434 engine is very desirable compared to those running 350's or 383's. No 383 can be built up to the level of a 427 while running pump gas with the same compression. The power and torque numbers down low in the rpm band are what make the 427 such an incredible engine, compared to the 383.