Non rail rocker on rail type valve?

[f18shack]

My 66 coupe was originally built in Nov 65, and the 289 was rebuilt in the late 70's. Based on the Nov 65 production date, I expected to find non-rail rockers with the short valvestems but instead found this:

I'm new to this, but it looks to me like I've got rail type valve stems and non-rail rockers. What do you all think?

What are the potential problems if I leave it this way?

[f18shack]

Bump

[frdnut]

Yes the tips do look pretty long and they likely put the wrong valves in during its rebuild..I would think that your valve train geometry would be off a little as you want the contact area of the rocker to be centered on the valve stem..It looks like your rocker would be running to the inside edge of the valve..You can probably correct this with a longer pushrod..I would pull off a rocker arm and take a look for any unusual wear marks on the tip or the rocker..If its a totally stock engine you might be able to get away with it...The bad geometry "may" accelerate your valve guide wear by side loading the valve..

[ZFORCE]

Your deduction looks correct. Since this engine has been this way for nearly 30 years, I can't see how it makes much difference, unless you are rebuilding and want to make it right. If you are going for stock, I'd go without the rail rockers as I've heard they can drop a valve, and yours came without them anyway, so stock to you would be non-rail rockers. However if you are not concerned with stock, I'd dump the whole setup for either E7 or GT/gt40 heads and a roller cam...that is if you don't want to go aluminum. There are tons of head choices that will far outperform what you have, it just depends on your needs/wants and budget.

[65fast]

They are definitely a non-rail rocker. As for the valve stem, I wasn't aware there was a difference between the stems from rail and non rail rockers. I am assuming the holes for your pushrods are slotted?

[f18shack]

Thanks for the responses. It has indeed been this way for awhile and that's a good point to just leave well enough alone!

The car idles a little rough, with vacuum jumping between 15-22, but runs fine at speed. I'm trying to figure out what I can afford to do with the top end of the motor. (The bottom end is in great shape as far as I can tell).

I don't want to get in the position where I spend more cash overhauling these stock heads than the cost of a new set...

I have a feeling I'll probably end up removing the stock top end, storing it, and going aftermarket when budget allows.

[Ponyman66]

I read your question shortly after you posted. Sorry for my delayed response, but I did a little research. According to the small block guru, Bob Mannel (and I DO use that term with utmost respect and sincerity!), no there is no problem with your heads/valves.

The non-rail rocker arm was used with the shorter exposed valve stem tip. However with change L10 (Sept. '65), the valves where changed to the longer exposed tips (and smaller diameter valve springs with different valve spring retainers). The non-rail rocker arms were STILL utilized. I have a set of heads that are identical with casting dates of 5J25 (Sept 24, '65). All the heads were cast with slotted push rod holes. The L10 change heads had a reduced radius around the valve guides. Change L11 resulted in round push rod holes and rail type rockers. Windsor Foundry heads received the L11 change before Cleveland Foundry heads did.

Since you have the valve cover pulled, look along the exhaust manifold side of the head, inside the galley. You'll see a "pad" with the casting date. Since your car had a scheduled build date of Nov '65, the heads were probably cast in Oct or early Nov. You should see "5kXX" or "5LXX" (replace the X's with numbers, that's the day of the week.

The short answer to your question is, no problem, that's how they're supposed to be! Just don't ever mix springs, retainers and valves. I've also been told never to use rail type rockers with the shorter exposed valves (pre- Sept '65), due to the possibility of the rails pressing down on the retainers to the point that the keepers can pop out (read...dropped valve!). I personally don't know of any case where this has ever happened, but it seems reasonable. Hope that answers your question!

BTW, I can't stress enough to folks, spend the bucks and buy a copy of Bob's book, "Mustang & Ford Small Block V8 1962-1969". It's not that expensive and you WON'T regret it!!

[f18shack]

My heads are 5J24, one day before yours, and are thermactors. Based on your research it makes more sense why they were set up this way.

The car has been within 30 miles of San Jose it's entire life. I've got all the thermactor stuff in a box in case I ever decide to go back to factory stock.

I think the plan for now will be to clean things up, reassemble, and save some money for a top end rebuild.

[Ponyman66]

Just curious, are your heads Cleveland castings? That would be a pretty cool little coincidence! Mine are non-thermactor heads (solid castings, no plugs). My car is a Metuchen unit with a scheduled build date of 28K. It's the Silver Blue GT in my sig pics.

[f18shack]

I think they're Cleveland. There's a casting mark that looks like an "F" inside a larger "C". Is that "Cleveland Foundry"?

My 66 is from San Jose with a scheduled build date code of "02K".