Thread: how to turn my 72 stock 402 BB 240hp into a respectable 400hp motor?

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Originally Posted by ital-rich

I'm confused with what I've read to this point about it here and there.

Well, I can understand that, there is so much bogus information out there on the web. But have no fear, you have landed squarely in the middle of a bunch of good-guy hotrodders who can and will help you out of your dilemma.

First thing you need to understand is that you will need more cubic inches. That sniveling little 402 might have been fine for hauling grandma to Bingo once a week, but it will fail miserably at hauling your butt on a fast street ride. I would begin advertising on craigslist and other venues for a 454 block or short block, stock bore or +0.030" oversize so that we can bore it to +0.060".

Hot Rod magazine penned a story back in 2013 that I still refer to, because the results are timeless for a good, strong 460 or 466 cubic inch big block that will take that Monte for a ride. Here's the story.......570 horsepower and 587 ft/lbs of torque in a streetable package......
https://www.hotrod.com/articles/crane-cams-dyno/
There are a few things that can be tweaked from the original story, but it is pretty much "as good as it gets" for a street motor as it is written. I would limit static compression ratio to 10.0:1 or somewhere close to that, depending on piston availability and might lighten up on the cam a tad, to help improve intake manifold vacuum for power brake function. Read through the article and then come back and ask questions. In the meantime, I'll be looking for a good set of forged pistons for you, as well as an aftermarket roller tappet camshaft and lifters. That flat tappet cam won't last long in a Big Block Chevy. They are famous for eating flat tappets.

Have no fear, jump in with both feet and enjoy yourself.

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Thanks for the input. That all sounds great but unfortunately at this time I'm on a tight budget for the car money after just paying for it. I'm just hoping to get to a respectable 400 hp with this engine if it's at all possible. Doing it properly, but still on a budget. I figured with this all stock 72 402 being a .030 over 396 that it might be a good enough lump to get me to that point some how. Also, I'd like to keep the car the #s matching car it currently is. Frame off resto and it's completely finished, just a dog of an engine is all. I figure as long as my gas mileage is already horrible, this anchor may as well grow a pair and do justice to the car. I also plan on using the A/C. lol.