[HO Kenny]

A friend just bought 68 400 engine with this on it.
The other side is a 13.

[johnta1]

Not from the factory on a 1968?


What's the date codes on the heads?

[HO Kenny]

They are 70 heads. The altered one was E220.

[johnta1]

Wonder if someone replaced a set of heads and they ground off the other number and stamped '3' so it would match the other head?


I would have thought a '2' would be better, being it could be a RA III head then?
(grind other head to match)

[necdb3]

If they are 70 heads on a 68 car, you answered your own question. Obviously, the heads have been altered but not by the factory.

[Formulabruce]

Originally Posted by necdb3

If they are 70 heads on a 68 car, you answered your own question. Obviously, the heads have been altered but not by the factory.

I could easily see these being altered by the factory, but in 1970. '
The haphazard way the grinding was done is a perfect example of Factory sloppy work. Since the heads are same , Its possible they just "fixed" a mistake this way.

['ol Pinion head]

Have pulled many many tons of core heads & engine blocks. In examining cyl heads, have always been leery of ground off and restamped casting numbers on big valve Dport heads. In the above, OP's, instance, its def possible that the grinding & stamping was done at Pontiac MI engine plant. Having examined more than a few factory ground off & restamped Pontiac cyl heads & blocks, not all of that grinding was done in a sloppy fashion. In the OP's case, definitely an oddity, but making the 12 casting head a 13, would love to examine it closer.

On the other front, many years ago I examined over a several year period, quite a few pair
of what had been 17's & 47's that had been similarly ground & made into 48's. Very convenient for one local source as he had carte blanche in his offtime in a family member's machine shop. The same prolific source also did his magic to numerous pairs of '70 model 16's & a few pair of '70 15's. Machined for reused stock big valves & screw in studs, even a fairly well seasoned Pontiac guy typically wouldn't know what he was looking at. As heads that were represented as the real deal, in order to authenticate such a pair of heads, most would go to the "we need to cc a few chambers"... Even doing so, & measuring the distance of the intake bolt holes to the head surface, might not prove that enlightening. As I mentioned many years ago to several acquaintances that were in the market for certain date ranges of 12's & 48's, the first thing to do before buying such a pair of heads would be to unbolt 4 rocker studs. Then examine the machined face of the figure 8 shaped pads that the pushrod guide plates are clamped down against. Converted press in stud heads like '69 47's & 70 model 16's will have a tapped hole in the center of each machined pad so press in stud guide plates can be bolted down. Factory big valve screw in stud heads lack these small holes. Have always wondered how many more pairs got this local treatment & were sold as "Ram Air" heads.

For the last few years have been helping a local on his '70 400 WT GTO. It has had a pair of E of '69 dated stamped 12's on his engine for many decades. He is the original owner of the GTO, an old school gearhead, & can't remember swapping out the heads. The clincher is the heads have been off & in and out of at least 3 machine shops in the '70's & 80's. Lot of swapouts were going on back in the day, so bells are going off in my head. Both casting numbers on the center exhaust ports are clearly stamped. Can def see this as plausible factory assembled on a very early, a late Gxx9 or Hxx9 WT 400 engine. The problem is the GTO has a late April body build & what was an original May of '70 door jamb decal. Having had several original D & E of '70 dated YZ & WS engines, & looked a many dozen more, all had fairly close dated raised casting number 12's.

[Baron Von Zeppelin]

Hardly anyone (hobbyist, enthusiast, scammer) would turn a 12 head into a 13.
But maybe turn a 13 into a 12 , in a hard up pinch.

And then to leave such noticeable evidence is even a bigger factor.

Don't think PMD assembly plant would have done this particular instance due to CC variance , and 13's should have been abundant at any given time.

I really think this instance was done as a service replacement by a zealous dealership. Anyone else putting much effort into covering their tracks a little, would have spent a few more seconds totally removing the ''2'' .
just my humbled opinion.

Have witnessed SR ground/restamped heads , they didn't try very hard to fool anyone with their techniques.

[SD455DJ]

Here's a stamped '2' on a 12 headed WS 400 from a '70 TA. The other head has the normal cast 12 and both are the same casting date D220 (same for the block)...original numbers matching motor.

Dennis