[Formidable]

Last week I sent off an OEM head to exhaust manifold stud and a genuine TRD header stud to ARP for them to match up and potentially fabricate a set for us. ARP responded with part numbers. These were purchased from summit racing.

The ARP stainless TRD header stud replacements and 12 point fasteners arrived today. Replaces the two studs for the sensor and the two studs that hold the runner. The head to exhaust manifold studs arrived as well but the broaches are a few mm longer than the OEM ones. Won't know fitment on those until I attempt installation.

These TRD stud replacements fit perfectly. Much stronger and nicer than the zinc coated mild steel ones that come with the headers, (comparison pic below). The zinc plated TRD studs were probably never meant for headers given how they corrode in no time.

The ARP stainless studs are expensive but they were designed to hold the head to the exhaust manifold. They are meant to withstand the heat as well as 18000 psi tensile strength - stronger than grade 8 steel. As an added bonus... they are gorgeous.

Part number in the pic below. The 304 stainless TRD headers are ceramic coated in 2000 degree satin grey ice from performance coatings in Washington. These along with the ARP studs will outlast the life of the vehicle.

ARP exhaust manifold PN# 400-8007 400-8027
ARP TRD header, (O2 sensor and runner studs) PN# 400-8001

[UnderFire]

I was just wondering about ARP manifold studs for my 3RZ. I wonder if they're the same.

[Formidable]

Update three years in the making. Torfab in Everett installed the TRD headers and confirmed the ARP studs fit.