Hi Hal
Yes i will be following up with maXspeeding rods on why the small end bore is not the correct specification. The difference in price will be around the different VAT generally at 20% in the EU versus 10% here in Australia
I don’t think for a road engine L19 bolts are necessary and they potentially introduce other problems.
This is from the ARP web site
ARP2000®: ARP2000 is an alloy steel that can be safely heat treated to a higher level, producing a greater strength material than 8740. While 8740 and ARP2000 share similar characteristics – ARP2000 is capable of achieving a clamp load at 220,000 psi. ARP2000 is used widely in short track and drag racing as an up-grade from 8740 chrome moly in both steel and aluminum rods. Stress corrosion and hydrogen embrittlement are typically not a problem, providing care is taken during installation.
L19: This is a premium steel that is processed to deliver superior strength and fatigue properties. L19 is a very high strength material compared to 8740 and ARP2000 and is capable of delivering a clamp load at 260,000 psi. It is primarily used in short track and drag racing applications where inertia loads exceed the clamping capability of ARP2000. Like most high strength, quench and temper steels – L19 requires special care during manufacturing to avoid hydrogen embrittlement. This material is easily contaminated and subject to stress corrosion. It must be kept well-oiled and not exposed to moisture.
My reading of this is that ARP 2000 bolts need less care due their lower sensitivity to hydrogen embrittlement and all the real world experience is they work OK in 8000+ rpm engines so no need for anything better such as L19 in a Twincam race engine let alone a road engine I believe. Getting the correct stretch on the rod bolts preferably by using a stretch dial gauge is much more important. You can do it by just torquing the bolts to their specified value using the ARP lube but without checking with a stretch gauge that is less accurate.
cheers
Rohan