The Stovebolt Site Forums The Shop Area Engine Shop 261 valve assembly confusion

Hello all.
Something about the valve assembly on my 261 doesn't look right. I bought this engine to rebuild.

Serial number: none. Not ground off, just blank.
Engine block: 3769925 date: C307
(No 3679925 casting in 1957. 67' replacement block?)

Head: 3836850 Date: 14G2

The rockers have the oil groove on the middle (57 style) but has the pinched off oil connector (59-62 style).
Additionally, a lead ball is jammed into the oil connector at the bottom. Why?

This engine has been rebuilt at some point in the past due to obvious signs. One of the springs on the rocker shaft was missing (small spring in the middle) which lead to the rocker getting beaten up.

Is the rocker shaft as transplant? What is going on with this thing.
Thanks!

Does the lead ball have a small hole bored thru it?

There is a member on this forum Pre ‘68 Dave, that has a good write-up about the different rocker oil supply systems that Chevy used on the 235/261 engines that may help you figure out your mystery. Here’s a [LINK]

As Phil posted - Dave's write-up is excellent and is very helpful.

Here are additional photos and information regarding 1938-1963 Stovebolt-engines' rocker-arm lubrication.

Could you show a complete picture of the side of your engine so I can get a better idea of the year?

Could you also post a picture of the casting code on the head and better picture on the date code on the head or just tell us what it is. From your picture it looks like 14C2 or 14G2.

The lead plug has no hole. It is completely blocked. The block does has the oil tube behind the side cover. Thanks for the links. I checked out both sites before I posted. Still confused as the lead plug.

Per my initial post: Head: 3836850 Date: 14G2
both the date code and the casting number of the head are under the valve cover. THe date code is on the left, the casting number (3836850) is on the right.

If you look at the "6" in the casting number, look straight down and you'll notice the faint outline of a "T" outside the valve cover. I'm assuming it means Truck.

My bottom line question is: What rockers to use with this configuration. Pre 57 or 58-62.


I'll try to get a pic of the side of the block later.

Neptune Green55 Maybe your rockers are mixed -up in location read the manuel,also look for wear on stems and rockers. older valve refacers had fixtures to dress the rockers.

Casting Codes and Serial number locations on 261 head and block (USA 261).

More pictures

It looks like a 1967 crate engine to me.
Center side mounts, that you’re engine has provisions for, started in 1958.
So with a C 30 7 block code it must be 1967.

Is this engine drilled the length of the engine through the lifter bores?

Yes.
So it's a 67 block and 62 head. I read that there weren't any 261 crate engines past 64.
I'll build the valve train per 62 specs. I'll have to get a completely new assembly anyways. This one is toast. Stands are cracked, shaft is worn, valves are worn.
That lead plug blocked all the supplied oil apparently.

Does your engine have a tube under the side cover like this?
Or was there plugs in the block?

Yes it has the tube as shown with a restrictor.

When you say restrictor, where is that? At the rear where the tube attaches to the block?

The restrictor

Crate engines are very interesting. They seem to use a mixture of parts.
That restrictor was only used up until 1957 on 235’s, I can’t confirm the year it changed on 261, as they did not always change at the same time as 235’s.
Rockers with centered grooves would be correct for this style of oil supply.