94 4.3 rocker arm studs

Hey guys, quick question. I bought a set of v-6 heads from ebay, yea, i know. They are great except for one thing. They have screw in rocker arm studs that don't fit OEM parts. Where do i find replacement screw in studs that will work with the stock rocker parts? I already have them on the truck, so you see my dilema. Needless to say, the guy i bought them from is no longer in bisiness.

Bummer!! A good auto machine shop should be able to point you in the right direction.

o'k, this thread has been so active i thought i would update it. With some web search, i have found the following, maybe true, maybe no, you know the web. Between 92 and 95 4.3 vortec engines were manufacteured in 2 different plants, tonowanda, and, romulus. The engines from tonowanda had screw in studs that were net lash, i.e., non adjustable, the 'nut' area of the stud is short, and, has a shoulder that seats the rocker arm ball in a singular position. Romulus had press in studs, the rockers are adjustable, therefore longer thread, and no shoulder between the thread and the shaft.the engines are identifiable by a stamp under the right cylender head as a T, or, an R. Apparently there is no crossover stud that can be used as is to enable the 2 heads to interchange, even though they carry the same head number, 10238181, i maybe in error on that. the romulis heads may carry the 10138181 stamp, i need to check that. The real problem is that there is no chevy replacement rocker arm stud to allow replacement to the adjustable for the use of the tonowanda heads on a romulus block. The closest is the lt1 studs, but, they have the 7/16-14 bottom studs, not the m8-1.25. I don't know about re-reaming from the metric to the sae, especially while mounted on the motor, so, i need smart guys, how about it? i really need some help.

So could you find a set of non adjustable roller rockers to bolt to the top of your heads?

Actually don't know tblake, i do know that the aftermarket roller rockers cost 200+, but, i'm not looking for that. All i want to do is used my stamped steel adjustable rocker arms, pushrods, and, lifters from my Romulus block withe the screw in stud Tonowanda heads, which are not adjustable. Thanks though

Maybe Roller Rockers was the wrong term to use. Don't 95+ Vortec motors have rockers/pedistals that you just tighten down to the head? Could you use those? Or am I wrong?

No, you are right, in 94 those were the net lash rockers only on Tonowanda built engines, and, those are exactly what i am trying to replace so i can use the original valve train in my romulus engine. Which came with adjustable valves. I don't know if i could just replace the rockers, rocker balls, and nuts with net lash parts from the tonowanda engines or not. All the reasearch i have done so far, nobody has gotten that far.

It would probably be best to remove the heads for re-tapping, then cut down the stud bosses to allow use of either type rocker. Of course, using net lash rockers would require a locking nut/top lock or something to retain adjustment better than stock self-lockers.

Once you tap the stud bosses for 7/16-14 you can do about anything you want.

http://www.wwdsltd.com/files/StudBossCutting.jpg

Thank you Blue Bowtie, i figured as much, they are already tapped to the m8/150,or 125, i was just hoping to not buy another set of head gaskets or head bolts, even though it hasn't been cranked since i put them on, obviously. Taped to 7/16ths i could use stock KS-1 rocker bolts. Another thought, could i enlarge them with a simple hand tap?

You could tap by hand but would need to be extremely careful to tap straight. That also wouldn't solve the bottom clearance problem for the hex collar on most studs, but you could try to locate collarless studs like Mr. Gasket used to offer.

I'm confused, the heads are already tapped, and, have studs withe hex 'collars'. The only problem is that they are a smaller metric, not 7/16ths. I was concerned about keeping the tap straight though. hmmm, from the pics i think i see what you mean, well, thanks, i guess i'm going to have to do more research.

I wonder if i could just get some net lash tonowanda rocker balls, nut's and rockers, using my pushrods, probably to simple? Well, i found some net lash rockers, balls, and, nuts at Rock Auto for 5 bucks a set. What are the chances they will work with my lifters and cam? I really need some help here. Thanks

Well, i went ahead and ordered the new net lash rockers, balls, and, nuts from Rock Auto, i'll let u know if net lash tonowanda head works on an adjustable rocker romulus engine.

well, boys, it lives. apparently there is no diff in push rod lenght it cranks right up. so another problem solved. now, i need a 292 inline-6 for my 87 gmc, anybody got one for sale?