Building a big-block these days is a far cry from what it was 10, 20, and 30 years ago. Today, even a 454 is considered small when compared to all the 496 strokers, 502s, 572s, and so on. The 427s are rare enough to almost be a non-factor because not a lot of them were built, and the 396/402 Rat has pretty much been kicked to the curb in many circles for being too small.
When it came time to pull the non-original 402 out of our AMD '67 Chevelle SS and rebuild it, we had quite the spirited debate over the course of action to follow. In the end, we decided a stroker was out because no one makes an aftermarket stroker crank (well, one that's realistically affordable for the readers anyway) that'll fit the smaller journal 396/402/427 block, and finding a 427 crank to use for a budget stroker isn't realistic because finding a loose 427 crank is like finding a vegan working in a cattle yard.
Ditch the 402 and find a 454 to build? That would've been an easy option, maybe add a stroker crank, and build a 496 like everyone else. Nothing wrong with 496s, but we didn't want to be like everyone else.
So, the question came up: How much can you get from a street-oriented 396/402? This engine build will provide the answer for those on a budget. That means high-dollar aluminum heads and roller camshafts are out. We're going to tear our '71 vintage 402 apart, stuff it with bulletproof parts (we'll also show lower cost alternatives for some parts to keep our real world theme) and see what we get.
The goal is to start with 400-425 pump-gas friendly horsepower, then grow from there. We're gonna try flat tappet cams, roller cams, different intakes, carbs, you name it along the way to see how much we can squeeze from the runt of the big-block litter. And along the way, probably have just a little bit of fun, too!
For our machine work and build, we went to Rollins Automotive in Gainesville, Florida. The father and son team of Greg and Jason Rollins has been building engines and selling speed parts for 50-plus years, based on tried and true racing experience.