Was reading about the Engine masters challenge and was wondering if a 425 steel crank would fit in a 430? What would be the cid? How many revs with a set of good stage 3-4 heads on it? This is just for debate, nothing to do today so let here it. :3gears:
Here was the thread when I started to research this....... http://www.v8buick.com/showthread.php?t=81534&highlight=main+journal
Definately when you consider the reduction in weight and more important is the reduction in main bearing size (2.5" fir the NH) you have more RPM capability. I've heard there have been guys that did it in the past,It would require main saddle spacers and aftermarket caps. The 401 and 430 have the same bore so a 430 with a NH crank would be 401CI's It's at this point(under 450CI) you could apply SBC tech to the build,We have 15 degree valve and flow numbers similar to some nice Chevy heads. I'm torn though as to the strength of the NH crank and 455 Block to put up with the 6500 to 7500+ RPM range that this would require.
I wonder if anybody has thought of a crank cradle. Take a t/a gridle and add a lower main section that the crank layes in, then the main caps clamp it down to the block. You could use aftermarket rods.As far as rpm's aren't there people getting close to that rpm already?
I think one of the issues is that the 455 crank had the huge mains in order to support the block from flexing. Taking that support away from the block, despite a girdle, might overstress the nailhead crank and/or block. Of course this might be a great low-buck crank for a new block with the correct sized mains machined into it. (sorry to add to you heartburn there Gary)
You could do it you need to Pin the Main Bearing Saddles to the Block. You would not have to run aftermarket Caps you could run Space Savers on the Main Caps. They use space Savers on Small block Chevys to put 350 cranks in 400s. The Nailhead crank is a Steel and is Very strong alot stronger than the Nodular Iron Cranks in the 400-430-455. You can have a Nailhead Crank welded and Stroked. Tommy Ivo's crank where welded and stroked. The Engines he had where like 460+ inches and there where 4 engines
Ok , I think that with pinning the main saddles and aftermarket 4-bolt main caps. We could say it would last to 7000-7500 rpm's. With the 430 bore could we use the Track elimator heads and flow enough to acheive the power at this rpm?
The block failures that I have seen rip the main webs completely out; no amount of pinning is going to fix that. None of those things address the block flexing issue, and although the forged crank would likely handle more flexing than a nodular crank, if the whole package flexes more it would likely still spell trouble. I'm not saying it can't be done, but a girdle is needed at the least. By the time all of the one-off work is done, It sounds to me like a Moldex crank will have been paid for. Unless you have a machine-shop in your spare bedroom.
Moldex's are Big Money and weight 18-29 Pounds more than a stock 455 cranks and you wait 6-12 months to get one. The Nailheads cranks are strong. Where you save Money you spend it some where else.
