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427 Big-Block Upgrade - Huffer Overhaul Part II

Machine Work Makes The Motor

Andrew Schear Nov 1, 2003
Sucp_0311_01_z 427_big_block Cleaning 2/27

Performance enthusiasts who've experienced using superchargers have come to realize that having a huffer on the engine is not that easy on parts. It's sort of like the price you pay for having the extra power. So when we tore apart our slightly aged big-block we were less than surprised to learn that the Rat had a lean cylinder, which we assessed was ultimately responsible for the demise of our '70s technology powerplant. Upon further inspection, we found that the GM steel crankshaft, 30 year-old Carrillo rods, and O-ringed block were in better than average condition. As the old saying goes, if it ain't broke, don't fix it!

Sucp_0311_02_z 427_big_block Machinist 3/27

Every project known to man requires adequate preparation of materials and knowledge of the subject matter. Whether the task at hand is car washing or house painting, certain steps are taken before the first fence post can be painted or the first coat of wax applied. Not to say that honing a cylinder bore at home can't be done, but after seeing the experts hone our 427, I'd think differently before attempting the art of block honing myself.

Sucp_0311_03_z 427_big_block Boring_machine 4/27

Part of the process of engine building is to incorporate the latest technology available and to put it to good use. We began the exploration to rebuild our 427-huffer with the intent of upgrading from a mechanical flat tappet camshaft to a mechanical roller tappet. We also planned on ditching the magneto in lieu of an MSD BTM electronic ignition. While a mag is great for many applications, electronic boost retard is the only way to go for a street blower setup. In addition to cam and ignition changes, we were determined to run a more streetable blower carburetor, namely the Holley HP 950 blower series.

But before we get ahead of ourselves, we'd better get to the projects at hand: machine work, rotational balancing, and cylinder head preparation. The chain of successful engine building starts with the guy at the end of the boring mill who is carefully calculating each cut. When .001 of an inch is considered sloppy work, you know you've chosen a worthy machinist.



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