PUSH ROD GUIDE PLATES?
 

i FOUND ME A SET OF OIL DRIPPERS FOR MY 65 421. .QUESTION? i NOTICED UPON INSTALLING MY OIL DRIPPERS, THE WAS NO PUSH ROD GUIDE PLATES ON MY CYLINDER HEADS? DID ALL 421 HO HAVE PUSH ROD GUIDE PLATES INSATALLED FROM THE FACTORY? IS IT A MUST TO HAVE THEM INSTALLEDED? i NOTICED AFTER MY LONG DRIVE LAST WEEKEND. i HAVE A NEW VALVE TRAIN NOISE?

Scott,dont think 65s had guide plates.Think 67 was the year.Tom

No guide plates until the 400 and 428 engines in 1967.

Tom V.

Scott,Tom.Most people don't know that the factory actually made guide plates for pre 67 heads.I have a set in factory packaging.I think I bought them from a board member years ago.They slip over the pressed in studs and were held down by the rockers.VERY rare.Tom

Those guide plates slip over the press-in studs and are held in place by the valve cover.

Seems like they’re a factory service part bandaid (at best, certainly not a performance part) for worn out pushrod guide slots that are machined into the cast iron heads.

Kind of useless unless you drill out the slots in the cast iron heads and allow the new guide plates to do all the locating otherwise you have two sets of guides fighting and interfering with each other.

If your slots in the heads are worn then the only good and durable solution is to remove the heads and convert them to screw in studs and aftermarket adjustable SBC guide plates that are held down by the new screw-in studs. This requires milling the stud bosses down a fair amount to allow for the lower hex portion of the studs and the thickness of the new guide plates.

Not simple or cheap.

Thank you guys for this information. My 67 GP did have the push rod guides.

You stated that after a long drive you noticed some new valve train noise.

Check to see if one or more of your rocker studs is backing out. Not at all uncommon on heads with press-in rocker studs, the factory did offer slightly oversized studs to repair this.

Truth. I was not aware of the "factory service part" Bart, (or maybe Early SD part with Pinned Press-in Rocker Studs, Tom S.

Tom V.

SD 62-63 had guide plates

Would pushrod guides be a good idea to use? I might have a bent pushrod? I'm going to check. Any input on using Comp Cams 1.52 Magnum Rockers and Hight Energy Pushrod kit?

I've got a set of those here at my shop. They have the different spacing for the earlier valves and rocker arms. I've never seen another set. I thought about having them reproduced but don't think there would be enough demand for them to justify the cost.

Agree with Tom to check your rocker nuts to see if they have backed out. Personally I would use a set of poly-locks to keep valve adjustment in place. Butler has them

Also look at the flat bottom of the rocker nuts for signs of cracking from the center hole out due to overtighting .

I have seen this at times with the result that they back off in time.

Straight edge over stud tops to ID a possible pulled stud

Digging deeper into this. The front rocker on the driver side was loose. This what I found. Put it back together and started the motor. I am getting oil at the rocker and inside the pushrod. I'm going to replace all pushrods and rockers. With a tape measure the pushrod measured 8 9/16". Is the the correct length rod for a 65 421HO? Suggestions on pushrods and rocker arms? Also going to check the rocker arm studs.

Scott,make sure you get 65-66 rockers,Paul Spots can hook
You up with what you need.Tom

HI TOM. DOES PAUL SPOTS HAVE A WEBSITE? PHONE NUMBER?
THANKS SCOTT

That is the correct length ( 8 9/16 “ ) push rod for the stock motor with a factory cam, yes!

Reasons for needing different length push rods may include.
Valve job done to heads with reusing valves that should have been replaced.

Milling of the heads or the block separate or in combination that (1) limit the adjustment range of the lifter (2) and or will move the needed rocker to valve stem contact out of its ideal range which is called proper geometry .

While you have things apart I would check the motors current geometry so you can sleep well knowing that the stock length push rods you put back in the motor are still what’s needed.

I had pmd guide plates on my 65 -77 heads,got them at parts dept. They were thin compared to 67s. I fastened them to my press in studs with a small tack weld. I did notice at least one corner had broken off after use. They did ,If i remember, that the valve cover gasket touched them.