[footjoy]

I had a set of #15 heads done. They did not have screw in studs. The shop that did the work put ARP studs in. The new studs are 7/16 x 20 so I will have to go with BBC nuts. Does anybody know if I will have to change rocker arms? The old stud was 3/8 I guess.

Thanks

Greg

[ponyakr]

You will need 7/16 nuts, or poly-locks.

Stock Pontiac rocker arms will work, because the part of the 3/8 stud that the rocker arm rides on is 7/16. Only the thread portion of the studs are 3/8. That's why they are called "bottleneck studs". They "bottleneck" down in size, from the 7/16 lower portion, to the upper 3/8 portion.

[footjoy]

Originally Posted by ponyakr

You will need 7/16 nuts.

The rocker arm are the same, because the part of the 3/8 stud that the rocker arm rides on is 7/16.

Thanks for the quick response now I have read up on adjusting the valve lash.

Thanks again

[ponyakr]

Originally Posted by footjoy

...now I have read up on adjusting the valve lash.

For HFT lifters, a quick over-simplification is to go 1/2 round tighter than zero lash. Some recommend 3/4 turn.

You can Google lots of info on the subject. Opinions differ on the details of this procedure.

[steve25]

Does the Cam you are running need lash?

Note that to run a Poly lock type set up the rocker studs need to have flat ground tops, if the are dished then a Ploy lock will not hold its adjustment!

The most fool proof way to adjust is by bringing one valve on each cylinder up to near full open, then the other valve is guaranteed to be on the base circle of the Cam and can be adjusted.

Any other cylinders that may have a open valve can be adjusted also.

Be sure to write down with valves you have adjusted, make a list of all 16 and cross them off as you go!

To lock down a poly lock type set up you make your adjustment with the big nut, then tighten down the Allen set , the rotate the big nut one quarter turn more to fully lock the adjustment you made.

Pulling all the plugs out first will make it easy to bar the motor over.

[footjoy]

Originally Posted by steve25

Does the Cam you are running need lash?

Note that to run a Poly lock type set up the rocker studs need to have flat ground tops, if the are dished then a Ploy lock will not hold its adjustment!

The most fool proof way to adjust is by bringing one valve on each cylinder up to near full open, then the other valve is guaranteed to be on the base circle of the Cam and can be adjusted.

Any other cylinders that may have a open valve can be adjusted also.

Be sure to write down with valves you have adjusted, make a list of all 16 and cross them off as you go!

To lock down a poly lock type set up you make your adjustment with the big nut, then tighten down the Allen set , the rotate the big nut one quarter turn more to fully lock the adjustment you made.

Pulling all the plugs out first will make it easy to bar the motor over.

Cam is set at.000