I just picked up a standard bore 4K29 Mustang block. I couldn't change the rear main cap to a C30E # from a C20E # no matter how long I stared at it.
The conecting rods have a C3AE-D #.
I read a wanted ad in the K Specific Parts section for Hi Po rods with part C3AE-D#.
Is this a Hi Po rod or a standard rod. All of the block parts appear to be original, including the FoMoCo pistons...
All 289 rods whether standard or Hipo have the C3AE-D casting number. The difference in the rods is that the Hipo rods use 3/8" rod bolts rather than the standard 5/16" bolts. The bolt size sounds like it would be simple to just bore out the 5/16" hole and install 3/8" bolts, right? If that were the case it would be easy to convert standard rods to Hipo rods and they would appear to be correct. Wrong!! If you bore out the rod bolt holes to fit a 3/8" bolt, the bolt will be into the rod bearing surface. Ford spread the bolt centers on the Hipo rods to allow the bolts to be changed to 3/8" bolts without the problem of getting into the bearing surface. The problem then is that the rod caps on standard rods do not have enough material to change the bolt center spread outward. This makes the caps different. It is a very subtle difference but that is the way it is. Bottom line is you either have Hipo rods or you don't. If they have 5/16" bolts, they are not Hipo rods.
-Fred-
Fred - I wonder how many times people tried to bore out the holes and failed. Great insite and advise.
Fred your so good at this, maybe you can tell every one about boss 302 rods?
just to point out the obvious, there are modern replacement connecting rods that can be used if needed or desired.
I'm all for originality, but it PAYS to remember these parts are 45+ years old, and every K code owner I know likes to spin the motor to 6000 rpm or beyond. That said, I'm still using my original rods. But If I was racing, I wouldn't hesitate to use a new rotating assembly.
http://www.summitracing.com/parts/ESP-5155F3D/
Z.
For “reliably” I think that I would be tempted to use modern parts on the inside and original parts on the outside.
I run both Boss 302 and 271HP rods on my engines. The rod itself is the same. However the machining for the rod bolt head is different though, the Boss 302 being 'Spot Faced' whereas the 271HP is 'Broach Cut'.
Many guys over the years have successfully enhanced their non 271HP rods with 11/32" rod bolts. A standard mod 'back in the day'.
Although any of us can destroy anything, it is not usually the connecting rod which goes first on an over-raced 271HP, it is the crank. But if you run out of oil or hydraulic a cylinder you could definitely hurt a rod.
Do the early rods have an oil passage drilled as opposed to the boss rods?
Some of the early rods have the oil passage but not all of them. The Boss 302 rods never have the oil passage.
-Fred-
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