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Originally Posted by Mr. P-Body
Bobzdar,
What's wrong with improving geometry and durability? Eagle and others offer a BBC rod in a 6.635" length (plenty "close enough"). That .050" in rod journal diameter is the difference between an engine notorious for rod bearing issues (Pontiac) and one that is not (BBC).
I suppose I don't fully understand the "leave it alone" mentality when dealing with mid-level and high-end race engines. These cranks aren't exactly intended for "replacement" use, as there is no need for such a strong crankshaft under 700 HP.
Maybe you could explain your rationale?
Jim
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Rules dictate I use stock geometries, cheap (thanks Baker, I knew I could count on you to shove your nose in where you can) when it comes to the cost of rods/pistons has nothing to do with it. It's also why I've been pushing for the raIV repro heads and would pony up the 50% up front if I could get 20 other people interested in ordering them - hardly cheap (unported originals hardly every show up for sale). I could probably get away with 6.635" rods...But I don't like 'cheating' however minor it might be. I suppose I could get rules clarification on if I could just run a smaller rod journal and be fine with the slightly longer rods, though I doubt they'd allow it if the car is faster than everyone else. Besided that, 6.625" gives about an ideal r/s ratio even if the rod journal is a little larger, though I don't anticipate an issue. If there were no geometry rules I'd be running a 4" stroke 6.8" rod combination; a 4.21" stroke (which would be legal as it was available in 2nd gen birds) is just way too much in friction and stress as you can't fit a rod long enough in it to relieve it, and it wouldn't be legal even if you could. I'm going road-racing, so I need the engine to live and not overheat or push the pistons out the side of the block or send shrapnel through the oil pan - hence also the desire for a forged crank. I hope that answers your question - I'd like the durability of the forged but can't modify the geometries.