[DoubleVision]

I got a set of 1997 Vortec heads going on my 4.3 V6. I removed the factory screw in studs as I planned to have standard SBC screw in studs installed.
When I removed the factory "net lash" studs I found something I didn't expect, Steel thread inserts in every hole. I was trying to avoid going the ARP adapter stud route as I've gotten wind that these have caused interferance problems with roller rockers which I plan to use.
How do I get around this? If the inserts were to be removed the hole would be too big to tap to the normal 3/8 screw in stud. Any help is appreciated.

[cobalt327]

I don't know what sizes you're working with in the Vortec heads, any chance you could use 3/8" inserts? There's always 7/16".

[DoubleVision]

I can't go the 7/16 route as I don't want to have to buy another set of rocker arms. I'm also not sure on the inserts for 3/8. It looks like I'll just have to take them to my machinist and see what he says. I think I see why they used inserts as the surrounding cast iron is rather thin.

[cobalt327]

Originally Posted by DoubleVision

I can't go the 7/16 route as I don't want to have to buy another set of rocker arms. I'm also not sure on the inserts for 3/8. It looks like I'll just have to take them to my machinist and see what he says. I think I see why they used inserts as the surrounding cast iron is rather thin.

Seems odd to me that they'd helicoil a hole in cast iron in the first place. I mean, what's the point?

Unless the head castings had holes originally made for pressed in studs and the insert was the only way to use the hole. I'm thinking if the heads were drilled for pressed in studs, the holes would be too big to thread them for what's in them now, so they'd have to h-coil them.

[SgtVic]

Almost anything that you want (short of the obvious parts, the rods and a couple other parts) for the Vortec 4.3 is interchangeable with sets from the sets from Vortec 350s. You wil just have couple extr parts in the sets. Check out the ARP rocker studs for the Vortec 350.

[MouseFink]

The threads in the 1997 V6 heads are M8-1.25 for stock M8 x M8-1.25 studs. If someone has installed inserts in those heads, they may have used M10-1.50 helicoils for ARP 100-7201, 3/8"-24 x M10- 1.50 adjustable conversion studs. A heli coil was unecessary because they could have used ARP 134-7201 3/8"-24 x M8-1.25 rocker studs. However, the ARP 100-7201 and 134-7201 conversion studs are too short for aluminum full roller rocker arms and 3/8"-24 poly-locks.

You can use ARP 134-7104, 3/8"-24 x 7/16"-14 rocker studs designed for a SBC V8. The effective length of those studs is .300" longer than the ARP 100-7201 and .155" longer than the ARP 134-7201 conversion studs. The ARP 134-7104 studs for a V8 are long enough to work with 3/8"-24 aluminum narrow body, full roller rocker arms on a V6. However, you must drill and tap the heads for 7/16-14 base threads and install #57615 Time Serts instead of helicoils. Those TimeSerts require a 37/64" counter bore.

Use self aligning rocker arms on V6 heads because the guide plates designed for a V8 are made for different valve and push rod spacing. You will also have to use ARP 233-3701 (12 pt.) head bolts for clearance of your torque wrench socket. You may or may not have to correct your push rod length, depending on which camshaft and roller lifters you use.

If the above solution is too costly, use stock or Comp Cams 1412 ball fulcrum, roller tip rocker arms with the ARP conversion studs that fit the helicoils already in the heads. Most people trying to solve the V6 rocker stud problem choose that option.

[bigdog7373]

Old thread, guys.