Chev 6.250 rods info

[toolmakeron]

We are currently using Scat H beam 6.250 ( 2.100 crank pin. .927 wrist pin) rods in a SBF 427. 4.155 bore, 4.00 stroke approx hp, 700, 72-7400 rpm. We are looking to upgrade the rods & looking around for some ideas where to go. I have a small preference for I beam rods.What are you guys running? Any suggestions? Olivers are the best, but just a bit too pricey for this go around,. We have had no issues at all with the Scat rods, but we are going up in compression ( 14.5) & up in cam & rpm. That's why the interest in different rods. Thanks guys, any ideas are welcome.....Still learnin Ron

 

[grumpyvette]

the first thing Id suggest is calling SCAT and asking, to talk with the ENGINEERS (NOT THE SALES GUYS) if the current rods are compatible with the engine build you are thinking about!
Id ask about recommended premium rod bolts and quench recommendations as at high rpms any rod stretches
while I have not used those particular SCAT rods, but I have built engines that used a heavy does of nitrous and exceeded 700hp that were fine with other SCAT rods
next ID suggest thinking about max piston speeds a 4" stroke crank will reach 4500 feet per minute which is about the limit for durability at about 6800rpm, and once you exceed that the chances of even great rods being damaged increases dramatically as does the chance of related valve train control issues.

connecting rods almost never fail in compression, but in tension, (like on the exhaust stroke where theres less resistance and the pistons playing snap the whip on the end of the connecting rods,) but the most common cause is due to valve train related failure where the piston bends a valve and then the bent valve gets hit by the piston, bending the rod as it tries to compress a bent or broken valve, simply because its the rod bolts that usually stretch allowing the bearings on the crank journal to loose support, resulting in loss of oil pressure and also allowing the piston to strike the heads or valves.
you might want to upgrade to top quality rod bolts in the current connecting rods, but ID certainly ask the engineers at SCAT!
things can get very expensive very quickly when you exceed 4500fpm in piston speed

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