Small Block Rocker Arms

[Tracy C.]

Seeing the recent post on big block rocker arms reminded me that I seen different markings on small block rockers as well.

I have a used set that is a mixed bag. Some have an "v", some a triangle, and some an "o" on the inside of the valve tip end of the rocker. What are the differences in these if any? I didn't find much in the archives.

Also, what wear conditions merit replacement and what is my best option for a good replacement set for a 63 L76?

thanks,
tc

[Terry M.]

Re: Small Block Rocker Arms

You had to go there, didn't you.

[Tracy C.]

Re: Small Block Rocker Arms

Yeah...I did.

I sold off all my "bubba go fast" parts (including a set of Harlan Sharpe rollers) at a recent swap meet and I'm tryng to decide if I should use an old original set of rockers or get something mo betta, but still in a stock configuration.

I did find an archive post from Joe Lucia regarding Crane "Nitro Carb" Rockers. They are priced at nearly $200 from Summit. Just wondering what other options I should consider.

tc

[Duke W.]

Re: Small Block Rocker Arms

I'm not sure about the different stamps. Joe L. will probably know. There were different rocker arms and pushrods used over the years of SB production - differences like heat treatment, but by the late seventies there was just one service replacement rocker and pushrod that covered all Corvette SB applications back to '55, and these were likely the best of the OE parts used over the years.

Existing rocker arms are usually okay for use if the wear surfaces appear burnished with no ridges or galling. Careful visual inspection and touch will usually reveal any problems.

When disassembling an engine, rockers, balls, and pushrods should be bagged as a set, and reinstalled as a set, preferably in the same location, but this is not critical. And make sure you mark the top end of the pushrod if it's not obvious so it doesn't go back in without a chance of reversing the ends.

Any used, matched set is okay if it passes the above inspection and junkyards are full of them, but new Sealed Power parts from NAPA are relatively inexpensive.

Most OE cams/springs are not that hard on the valve train and these components usually don't need to be replaced when an engine is rebuilt.

My philosophy is to use as many existing components as possible, especially if they are known to be durable and are not subject to much wear. This saves money, and what you save can be put into buying more durable components where they are called for (like most 283/327 connecting rods) or internal modifications to improve performance, like head massaging.

Duke

[Tracy C.]

Re: Small Block Rocker Arms

Thank you Duke.

The pushrods were gonzo, but I did keep the rocker ball and arms wired together. They are now taking a bath in carb cleaner for a couple of days. I'll check for condition when clean. I did see some light rust on some of the rocker ball wear surfaces.

tc

[Domenic T.]

Re: Small Block Rocker Arms

Tracy,
I'm not going to pull my valve cover, or am I? But I think the O is the one that was for the HP springs on our SBs.

Not sure but Joe will set us straight.

DOM

[John H.]

Re: Small Block Rocker Arms

I know that the "o"-stamped rocker arms were used on Camaro Z/28 302 solid-lifter engines, and not on any of the companion Camaro hydraulic-lifter engines; I think it had to do with the type of heat-treat they got.

Most hydraulic-lifter small-blocks I've torn down have had the "triangle"-stamped rockers.

[Terry M.]

Re: Small Block Rocker Arms

Tracy,
I'm not going to pull my valve cover, or am I? But I think the O is the one that was for the HP springs on our SBs.

Not sure but Joe will set us straight.

DOM

That thought crossed my mind, but I aqm not sure I want to show off my Rev Locks.

[Bob J.]

Re: Small Block Rocker Arms

I know that the "o"-stamped rocker arms were used on Camaro Z/28 302 solid-lifter engines, and not on any of the companion Camaro hydraulic-lifter engines; I think it had to do with the type of heat-treat they got.

Most hydraulic-lifter small-blocks I've torn down have had the "triangle"-stamped rockers.

Nice pic John.
Yes, the "O" was used for special high performance small blocks and there were different configurations of the "O" depending on which year built. Bob

[Tracy C.]

Re: Small Block Rocker Arms

I know that the "o"-stamped rocker arms were used on Camaro Z/28 302 solid-lifter engines, and not on any of the companion Camaro hydraulic-lifter engines; I think it had to do with the type of heat-treat they got.

Most hydraulic-lifter small-blocks I've torn down have had the "triangle"-stamped rockers.

Thank you John...those springs look like they have the splash caps over the top. My donor heads also had them. Should I reuse them? Seems like they would add reciprocating mass to the valve train.

[John H.]

Re: Small Block Rocker Arms

Thank you John...those springs look like they have the splash caps over the top. My donor heads also had them. Should I reuse them? Seems like they would add reciprocating mass to the valve train.

Tracy -

Chevy used the caps (shields) on all small-blocks; they were an integral part of the oil control system. They've never kept any of my solid-lifter small-blocks from winding to the moon with factory cam and springs.

[Tracy C.]

Re: Small Block Rocker Arms

Tracy -

Chevy used the caps (shields) on all small-blocks; they were an integral part of the oil control system. They've never kept any of my solid-lifter small-blocks from winding to the moon with factory cam and springs.

Thanks, One advantage (other than oil splash control on the valve stem) that I can see is they also help keep the spring retainer centered on the valve spring. Without them, the retainer fit on the top of the spring seems sloppy.

tc

[Clem Z.]

Re: Small Block Rocker Arms

I'm not sure about the different stamps. Joe L. will probably know. There were different rocker arms and pushrods used over the years of SB production - differences like heat treatment, but by the late seventies there was just one service replacement rocker and pushrod that covered all Corvette SB applications back to '55, and these were likely the best of the OE parts used over the years.

Existing rocker arms are usually okay for use if the wear surfaces appear burnished with no ridges or galling. Careful visual inspection and touch will usually reveal any problems.

When disassembling an engine, rockers, balls, and pushrods should be bagged as a set, and reinstalled as a set, preferably in the same location, but this is not critical. And make sure you mark the top end of the pushrod if it's not obvious so it doesn't go back in without a chance of reversing the ends.

Any used, matched set is okay if it passes the above inspection and junkyards are full of them, but new Sealed Power parts from NAPA are relatively inexpensive.

Most OE cams/springs are not that hard on the valve train and these components usually don't need to be replaced when an engine is rebuilt.

My philosophy is to use as many existing components as possible, especially if they are known to be durable and are not subject to much wear. This saves money, and what you save can be put into buying more durable components where they are called for (like most 283/327 connecting rods) or internal modifications to improve performance, like head massaging.

Duke

i was told by a GM engineer the reason the later ones had problems was the producer went from a 7 step manufacturing process to a 3 step process and this caused the durability problems. we had problems with them in race engines where the rules say you must use stock rockers.

[Joe L.]

Re: Small Block Rocker Arms

Seeing the recent post on big block rocker arms reminded me that I seen different markings on small block rockers as well.

I have a used set that is a mixed bag. Some have an "v", some a triangle, and some an "o" on the inside of the valve tip end of the rocker. What are the differences in these if any? I didn't find much in the archives.

Also, what wear conditions merit replacement and what is my best option for a good replacement set for a 63 L76?

thanks,
tc

Tracy------


There were 5 different rocker arms used on Chevrolet small blocks over the 1955-95 period. Each was also supercessive to the former for SERVICE. These are as follows:

1955-57----GM #3837175----I don't know what was stamped on these;(does anyone know for my edification?)

1958-63-----GM #3746241-----I don't know what was stamped on these; (does anyone know for my edification?)

1964-69-----GM #3843359-----These were usually stamped "O" but some late 60's examples were stamped with a "triangle";

1970-86-----GM #3974290-----Stamped with a "V"

1987-95-----GM #10089648-----Guided type rocker


The GM #3974290 were the best of the non-guided type rockers. However, these were discontinued from SERVICE in July, 1989 and replaced by the GM #10089648 guided-type rockers. The 10089648 are the only stamped steel rocker arms currently available from GM for Gen I and Gen II small blocks.

[Timothy B.]

Re: Small Block Rocker Arms

Joe,

Just to be clear, can you use the guided type rocker arm on a stock small block head with or without pushrod guides?