[grivera]

When converting heads that already have factory screw in studs, like 6x8s to a BB Chevy style stud, do the heads to be re-drilled and tapped? Or does ARP make a conversion stud that screws into the factory threaded holes? If so anyone know the part number?

[b-man]

The BBC studs are a direct fit. The factory threaded holes are 7/16-14 on both Pontiac and BBC.

There are number of different lengths available.

Keep in mind that sometimes you need to shorten the bottom threads by about 1/8” so they don’t bottom out.

I used these on my 421 HO engine, 101 - 7101 ARP Rocker Arm Stud Kit. The heads were originally equipped with press-in studs but I had 7/16-14 helicoils installed. Once the original studs were removed the holes are too big to simply tap for 7/16-14 threads.

[grivera]

Thank you

[b-man]

For heads that originally came with press-in studs you can buy the ARP conversion studs that have 1/2-13 bottom threads, eliminating the need for helicoil inserts.

Conversion studs aren’t used on heads that came with screw-in studs from the factory.

[steve25]

The part number you need for a set of 16 studs from Butler performance is pep-prk-382b-16.

[grivera]

Thanks all

[78w72]

You dont really need ARP studs, stock BBC studs are plenty strong for most cams used on the street & probably even some bigger cams.

Can buy OEM type BBC studs for a lot less than ARP, spotts on ebay sells them for about $40, thats what I plan to do to convert stock bottleneck studs on 6x heads, other sellers are even cheaper. can also use good condition used studs that a machine shop would probably sell for $20 or give away.

[Skip Fix]

The only problem I had with some stock type BBC studs was the hex was large and tall enough for the bigger body on a HS aluminum rocker to drag on, ARP smoother and a little shorter. But I used the BBC I got from HO Racing on stamped rockers no problem.

[blueghoast]

Originally Posted by grivera

Thanks all

You can also get them at speedmaster to for around $20.00 thats where I
buy mine from.

GT

[b-man]

Or you could use the higher quality ARP that will flex less than the generic ones.

A little extra money for a more stable valvetrain is worth it to me.

Not to mention that some of the cheaper studs might not have the tops ground flat for sure seating of the polylock nuts. This isn’t optional, the polylocks won’t stay tight without that extra feature that many of the lesser quality studs don’t have.

Sure you can face them off in your lathe if you have one or have them ground flat but it makes sense just to buy the ARP studs to begin with.

[S.F.]

Hello!

In my 1971 #96 heads I use the ARP and steinlessteel PRW 1:65 from Butler.

Then I shorten the polylockbolt aprox. 5mm in a lathe and with the use of the thicker valvecover gasket i use OEM valve cover ant it look original under hood.

The Polylock that come with the PRW 1:65 steinlessteel rollerrockers was thin in the bottom and after a turn on the lathe they were a more solid fit.

I run Crower 60243 cam with 1:65 rollerrocker and have to lower the spring, Crower 404, in the heads and lower the valve steering and I put on possitive seal on in and exhaust valves with OEM hight.

The younger Butler told me the valve was to short.

Jim Butler told me to meassure and machine carefully so I did and it worked very vell.

I will later convert my pressed in rockerbolts for ARP and meassure if I need to trimm the botton for fit.

Thank You from S.F. in Sweden.