[BlueMach1]

Well, it's always something. Just went to install my comp cams pro magnum roller rockers and found out that I have bought the wrong ones...DOH! I thought 3/8's was the thread size that the retainer screwed onto. It is 7/16. Man, I bought these from JEGs last June. Do you think they will let me exchange for the correct set?

 

[camachinist]

Clarify... you're saying you have rocker arms for 7/16" studs (where the bottom and top are both 7/16", just different pitch) and your existing studs have 3/8" tops? If so, just get 7/16" studs; they're cheap...I did this for the Edelbrocks on the race car. IIRC, they cost about 25 bucks or so for ARP's. I'm assuming you have the poly-locks for 7/16" as well. You can sell the 3/8" studs to someone rebuilding.

You could try for an exchange but results are doubtful. Good luck!

Upon re-reading, it appears you may have the reverse....
In that case, get 3/8" studs and poly-locks and sell the 7/16" stuff....

 

[camachinist]

Oh, BTW, what kind of cam and spring open pressures are you running?

 

[BlueMach1]

I have the 249-1331-16 comp cams rockers. I should have got the 249-1332-16. (I believe)

I am installing on Edelbrock 6022 performer RPM heads. These have the valves, studs, guide plates and springs already installed.

The stud must be 3/8s on the side that engages with head and 7/16 one the upper portion.

For sure what I have is wrong because the lock wont even engage the threads.

Am I just running low on coffee???????

 

[BlueMach1]

Edelbrock states:
spring diameter = 1.45"
spring height = 1.80"
spring seat pressure = 110 - 120 lbs.
Max. Lift = .575"

My Cam is Comp Cams XE274H-10 (P/N 35-246-3)
Gross Valve Lift:
Intake = .510
Exhaust = .523

 

[camachinist]

The 1331's are for a 3/8" stud. If you have 3/8" studs, they should fit. When you say the poly locks won't thread on, do you mean the threads won't start (lock too small) or the threads just slip over (lock too big).

Clarify the above to make sure I'm understanding things correctly. Edelbrocks generally come with 3/8" studs. That means the bottom which screws into the head is 7/16" 14 tpi and the top which engages the rocker arm is 3/8" 24 tpi. Is that what you have and do the rocker arms fit tightly over that stud?

 

[camachinist]

I have a slightly larger camshaft in the race car and went to 7/16" studs and rockers for a little extra margin of safety. I'm running a similar head, although they're circa 1995. No problems. Rockers are Crane Energizers.

Likely 3/8" studs will be OK with the stock Edelbrock spec'd springs...

 

[BlueMach1]

The locks just slip right over the studs.

Maybe I have this ass backwards - 7/16 is larger than 3/8. So, the locks that were sent to me must be 7/16 when they were supposed to be 3/8?

 

[camachinist]

If the rockers fit tightly over the studs (no wobbling), then they just sent the wrong locks. You can call their support line (or e-mail them) and ask for the correct ones...