Can anyone identify this stamping on the side of a cylinder head? This is a B head. I have a few other heads and they don't have anything like this on them. The heads are somewhat mystery heads as they were redone over 25 years ago and I believe they had a lot taken off to increase compression.

Thanks!

Pat

 

I think that's a 66 Toronado head.

 

just the front of the passenger side head was stamped 1965-'67 (maybe earlier ??)
N-prefix (engine unit number) T-suffix = 1966 Toronado 425

 

^^^This.
N = 425 4bbl motor
T = Toronado application
The other digits are just the engine sequence number. This number would have appeared on the Protect-O-Plate for the car it came in, allowing you to trace this engine to a VIN for warranty purposes.

 

Okay, thanks for the clarification I have not noticed this on heads before. I pulled them off a 66 or 67 Toronado in a junkyard many years ago.

I take it all heads were not stamped? I have 2 sets of E heads with no stamping like this on them.

I was hoping it was a stamp from the machinist that worked on these heads and told me how much was shaved off.

Pat

 

Pre Jan 1 68, the engines were stamped, on the head, front side, of the passenger head with Letter Code [Engine Number] Sometimes another letter. Since the heads are identical, 50% of heads got no stamps, being on the driver's side.

Once the Federal requirement to stamp the vin derivative on the engine occurred, that took over for engine ID, and that's on the block pad under the front of the left head.

 

Actually, Olds made the change at the start of the 1968 model year in mid-1967. All 1967 model year and older Olds engines have the engine unit number stamp on the front of the passenger side head. Note that if the heads have ever been off, there's a 50-50 chance they were swapped at reinstallation, which puts the stamp on the back of the driver side head.

All 1968 model year and newer Olds engines have a VIN derivative stamp on the block. In addition, there is an engine unit number stamped on the oil fill tube. The first digit of this number on the oil tube is the model year.

 

Have 70 442 right head pad has 6601 stamped on it, is this a seq.# or what?

 

Post a pic.

 

My bad . Thanks for asking for pic upon further review I was upside down.

 

That's not a factory mark. These heads have been redone. That's a machine shop mark. I bet there's one on the end of the other head also.

 

A machine shop that does heads can measure the chamber volume (cc the heads).

 

They can also measure how much was removed. If they are just resurfacing the head gasket side of the head, they don't need to c.c. them. The amount removed could affect the push rod length, c.c. would not be as helpful.

 

What would they reference from if you don't have an additional stock head?

 

I remember there was a measurement from the machined pad to the cylinder head deck surface you could use to determine if the head had been cut. I don’t remember the actual number, I know it’s listed in the old Mondello Olds tech manual. I have my copy at home, unfortunately I’m at work now.

 

What we have in this thread is TWO members asking slightly different questions.
#1 FasyEddy was trying to figure out how much was removed from his heads. #2 gglow asking about a number stamped on his heads and then wondered how much his machinist removed from his heads.

Matt69Olds has a reference dimension he can't provide right now. The next best thing would be to ask someone on here what thickness they have on some stock heads.

FastEddy can probably figure out if a lot was removed from his heads by comparing what Matt can tell us, or finding a stock head to measure the thickness.

gglow may not be able to know what was removed by his machinist because it could be a little as .005-.010" removed to re-surface the heads.

Either way, cc's will not be helpful. Due to manufacturing tolerances, the finished head thickness from Oldsmobile could vary as much as .005-.010". This would mean a variance of as much as 2 cc's on BBO heads.

gglow's machinist should have measured and recorded the head thickness before and after machining. gglow should ask his machinist how much was removed.

 

Huh, go figure. I'd use the CC measurements to calculate compression, then adjust the valvetrain accordingly. I don't see where knowing what was removed tells you anything useful other than what was removed.
Just hope they took the same amount off the intake face, so you don't get pigeon holed on a cut-to-fit manifold.

 

Thanks for the info Joe.

 

this is a C head would you know what the R stands for

 

The R prefix with a T suffix pegs this head as coming from a 1967 Toronado with high compression.