I have a set of Carrillo rods with SPS CARR rod bolts. I normally change out my typical ARP bolts every two or three rebuilds, but they cost about $125 a set for four rods. SPS CARR are going to cost me just about $400 for four rods (I'm in Canada, we have exchange, duty, shipping charges, etc, that you guys may not have). I hate to toss them just because I have a habit of changing rod bolts.
I went to the Carrillo web site and they say this:
Under racing conditions, we suggest that the H11 bolts be changed periodically. In comparison, the Multiphase® bolt (SPS-CARR) is designed to be a non-replacement type fastener.
I don't know the original pre-install length of these bolts. If the threads are perfect, if they stretch what they should at the right torque, how long can you use these for? This is a vintage race Cooper S engine that is turned to 7500 rpm.