Thread: What crank is this

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Well let me start by giving credit where it's due. the "drill bit test" was devised by Dave Schouweiller or "Shoe" as he's known over on the net54 forum. It's a simple field test to see what cyl wallcores FE and FT blocks were cast with. This will give you the basic idea what your dealing with thickness wise and a sonic map should be performed when boring a block close to it's natural limits. It's measured out in 64"'s and you can convert your drill bits to suit math wise. You use the drill bit shank to gap the space between each cyl wallcore. You access this area by knocking out all 6 freeze plugs on the side of the block. 352,360 and 390 blocks commonly fit a 17/64" drill bit shank between the wallcores. 428 and some 406 blocks fit a 13/64" drill bit shank. 427's and some 406's that have 427 wallcores use a 7/64" bit. some 427 blocks have been found to fit a 5/64" bit and those are pretty thick cyl walls. There is also a allen wrench test but I've found the drill bits more accurate. STD 428 blocks found in Tbirds don't have the HD cranksaddle webbing so don't be discouraged about that. That D2 block might be pretty thick so check that one also. Those can be good blocks. some have nodular maincaps. Look for the "ladybug, bump or wart" as they are called ontop of the maincap. You should also see a brinnel indentation on the side of one or more caps if the ladybug is present. If you don't understand any of this let me know and I'll try to explain it better.
Good luck...

G.

Thanks Again. I Will Be Doing That Test. Thanks Scs