C3 - Big block build
Safety Car
Joined: Nov 2008
Posts: 3,716
Likes: 551
From: Seattle Washington
Just be REALLY careful when choosing a crank for your BB engine. Knowing that they made Cast and Forged Crankshafts for these beasts after 50+ years. Most of the "used" GM cranks out there have dozens of small stress cracks all over the bottom end.
The crank I had was not worth doing anything with, as it was one of the worst I had seen under magnetic testing. As I purchased almost a dozen used Forged Crankshafts made by GM and every one of them had cracks all over the place. I was shocked to find that many stress cracks on the important places/surfaces of the crankshafts. I would not take a chance on any of the cranks because I wanted a High compression 427.
One speed shop owner even told me that "I should use one of the forged cranks (with stress cracks) as I wouldn't stress it enough to hurt anything". NOT in my engine. I ended up going thru so many cranks shafts to find ONE perfect example with Zero cracks. I would be very careful when looking at building your beastly BB. It might be more expensive but if you go high horsepower BB you will need a good solid block and a crack-free Crankshaft possibly from the aftermarket.
For me and my beastly 427 Forged parts were used in the short block.
The crank I had was not worth doing anything with, as it was one of the worst I had seen under magnetic testing. As I purchased almost a dozen used Forged Crankshafts made by GM and every one of them had cracks all over the place. I was shocked to find that many stress cracks on the important places/surfaces of the crankshafts. I would not take a chance on any of the cranks because I wanted a High compression 427.
One speed shop owner even told me that "I should use one of the forged cranks (with stress cracks) as I wouldn't stress it enough to hurt anything". NOT in my engine. I ended up going thru so many cranks shafts to find ONE perfect example with Zero cracks. I would be very careful when looking at building your beastly BB. It might be more expensive but if you go high horsepower BB you will need a good solid block and a crack-free Crankshaft possibly from the aftermarket.
For me and my beastly 427 Forged parts were used in the short block.
Race Director
Joined: Mar 2016
Posts: 14,321
Likes: 8,124
From: Napa Valley California
I'm building two 1966 " Restoration" 427's. I was a bit surprised at the lack of aftermarket 427 Cranks on the market. I came up with a couple of 263 Cranks. I assume any of the USA brand Crank manufactures could custom grind a 427. 454 cranks are easy peazy and even 496 are plentiful. Apparently in today's world everybody wants Cubic Centemeters and not Correctness.
John the owner and his crew have been building engines for six decades.
John has a warehouse filled with cranks, blocks, heads, rods and most major components for all engine types.
He may have what you are looking for and he won’t sell you junk!
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,149
Likes: 9,279
From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
The big chamber rectangular port heads make for nice bragging rights, but may not be the best choice for your build, unless you’re planning to run it strictly on the race track with high compression at high rpm’s.
If your building an engine for mid range torque and top rpm under 6000 rpm then a better head combination would be heads with oval ports and the combustion chamber to match the rest of your engine build.
Those big chamber rectangular ports will kill your performance at lower and mid range rpm.
If your building an engine for mid range torque and top rpm under 6000 rpm then a better head combination would be heads with oval ports and the combustion chamber to match the rest of your engine build.
Those big chamber rectangular ports will kill your performance at lower and mid range rpm.
