ARP Head Stud Differences?

[sschambers]

Ok I've searched for this answer everywhere and I can't find anything.

I'm going to be putting my motor back together soon and I'm down to the last couple of parts I still need to buy. 1. Exhaust manifold. 2. ARP Head Studs.

I've been looking at different web sites and most of them sell 2 different kinds of ARP head studs for my 2g 7-bolt 4g63.

1. Part # 207-4203 (12 point nuts)
2. Part # 207-4702 (12 point nuts with undercut studs)

Part # 207-4203 is $91.95 from Summit.
Part # 207-4702 is $129.95 from Summit.

Both part # descriptions are the same. Both sets are for the 7-bolt 4g63. But...

What is the difference between the two? Which set is better? My assumption would be that the ones that cost more would be "better", but I would also assume either set is "better" than stock.

If anyone could give me an answer I'd appreciate it.

Thanks,

Steve

 

[99gst_racer]

The difference is the undercut studs. They narrow down the diameter of the un-threaded portion of the stud. This aids in maintaining an even and consistent clamping force while everything is expanding and contracting. They are ideal for engines with power adders like a turbo or nitrous, and for engines that use multiple length studs.

It's up to you whether that added benefit is worth the additional cost.