https://orangecounty.craigslist.org/...157172480.html

 

I'd bet those chambers are a bunch bigger than 69.75ccs

first I've heard of a difference between 1968 & 1969 model year "D" heads ???

 

The exhaust dividers look like they're welded flush but the exhaust crossovers look smaller but still open. Jmo.

 

The exhaust divider may not be welded, the exhaust surface may be milled back to make the divider flush. I looked at my heads vs the pictures and it’s hard to tell if that is the case. It may be a challenge with manifolds if so.

There are two varieties of D heads - some have the small oval at the intake interface, some have the normal Olds rectangle.

Regarding the crossover, on the D, F, and maybe H heads - only one exhaust port feeds the intake crossover, not both per head like the normal Olds heads. It’s nice because you can block the crossover with sheet metal at the intake and have 8 individual exhaust ports. I’ve never checked KA’s to see how they are configured.

As hurst68olds noted, nobody has yet documented a set of virgin chamber volumes at 69.75cc. It’s an NHRA minimum propagated by the Mondello book back in the day. Mine CC’d 82cc as virgin, others have been >80cc.

Not bashing the seller or part, his pictures are great, price is reasonable, but as with any 50 year old used performance heads, there may be some surprises like the milling.

The other odd thing is someone put rotators on the valve springs, you normally need deep spring pockets with those for adequate spring height, like the later Olds heads had.