About 15 years ago I purchased a brand new in the box Ford Motorsport 3.85" forged stroker crank.  Its not offered anymore and the original box it came in is long gone.  Does anyone remember the part number for this crank?  It was for a 351W  but had 2.75" diameter main journals on it and 2.100" Chevy size rod journals on it.  You had to use the M-6306-A351 spacer on the crank nose to make it fit in the Cleveland block.  Years ago I was doing a build for my Pantera with 6.00 Chevy rods, Yates "C3" heads, and custom pistons suited for Yates Nascar heads.  Never assembled the motor. I remember the piston/head and cylinder head chamber volume combo yielded about 12:1 compression.  I had the crankshaft "0" balanced,so it took quite a bit of Mallory metal to do it (and cost!).  I remember we had a slight crank throw to to piston skirt interference issue, and since we were adding Mallory metal to "0" balance, we trimmed each crank journal for a few degrees before and after TDC to clear each piston skirt and I think we trimmed the piston skirts a bit too.  This combo was with 6.000" Chevy size journal rods.  It was quite the expensive set up as the valve train used a  Jesel 1.8 ratio rocker arm system with the C3 Yates heads, which had different vave angles than the Cleveland heads.  I remember we checked piston pin height location closely as it was 1.225" down in the piston to fit the 9.2" deck Cleveland block.

Original Post

Those crank ass'ys were once popular among Ford dirt track racers (winged and not) that ran in the 410ci class. Most used Fontana aluminum blocks and Ford SVO heads. They were reliable(!) at around 875-900 bhp & 9000 rpms on methanol. Haven't seen one since the mid-'90s and don't know who made them for Ford. 

We trimmed the crankshaft counter weights slightly for a few degrees rotation to clear the piston skirts, not the journals as I had written!  We could have  probably used 6.2 inch long rods, but then the piston pin location would have invaded the rings location with the 9.2" deck height Cleveland block. We were also sensitive to pistons rocking in the bores with too short skirts. This entire build with this combination of components was not the easiest to do!  Lot of attention to detail and learned a lot on it!  I remember the machinist doing the Mallory work telling me the crank material was tough as hell to machine on the counterweights.  I still have this whole engine assembly on the "shelf" today, not assembled!  

 We started with a real 1972 casting 4 bolt main block, too!  Probably getting too old to deal with all this performance in a Pantera, as I bought the car new in March of 1975, and still have it.  Had the original engine out and modified with closed chamber heads and forged flat top pistons in late 1975.  Engine had the wrong balance flywheel on it.  Ford never figured that out, even though they gave me a new short block under warranty as the motor wiped out 2 sets of rear rod bearings  and rear set of main bearings in 4000 miles.   Darn external balanced motors!   Took a balance job during my build to figure that out.  Still runs good, even by today's standards once cam, high rise, and Big Throats were added back then on that build.  Oh, the memories, and dealing with Ford factory Service Reps back then.  Dealer Service/Mechanics weren't sharp enough to figure out the flywheel balance problem either.  Re-used it. Even with a new warranty factory shortblock.  You would think they would give me a new correct vibration damper and flywheel when they did the new factory shortblock under warranty.  On my build, found out the replacement factory short block wasn't a 4 bolt main item.  Boy, was I pissed.  Too late then!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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