[Dragncar]

Originally Posted by Rocky Rotella

Grandam1979, can you attach some pictures of the new SR block? And are the numbers cast or stamped? I'd love to add them to my collection.

Concerning the numbers, as Johnta1 pointed out, I've been tracking SR blocks for years. While they're certainly not rare, there aren't as many out there as people might expect.

What I can tell you is that I can no correlation to the sequence following "SR8" (which signified Service Replacement 8-cylinder). Most are higher than those produced during the preceding calendar year, but some are lower. Some produced in the same model year may be 10,000 units off. I don't know that Pontiac kept any specific record of them.

I supposed the bigger question is, how many warranty failures did Pontiac have that required a new fitted block (block, main caps, and pistons) each year? If I had to guess, I'd say it's a relatively low number. And combine that with the sheer number of fitted blocks Pontiac sold over the parts counter to racers, the SR blocks that are out there, not all were destined for warranty repair.

If anyone has any other insight on the sequencing (or paperwork that clarifies it), I'd be interested in learning more!

Whitmore told me the 1970 10-1 455 with 64 heads ( I have one) had a fair amount of comebacks due to people not running premium fuel. It had cast pistons and they cracked and took out a few engines. He was a dealer mechanic back in the day.

[Rocky Rotella]

Originally Posted by Dragncar

Whitmore told me the 1970 10-1 455 with 64 heads ( I have one) had a fair amount of comebacks due to people not running premium fuel. It had cast pistons and they cracked and took out a few engines. He was a dealer mechanic back in the day.

Thanks, I could certainly see that happening.

The question is, did Pontiac ship 10,000 (or more) SR blocks each year? Or were SR numbers picked at random. I just don't know at this point. But I'll keep looking!

[TRADERMIKE 2012]

Originally Posted by Rocky Rotella

Thanks, I could certainly see that happening.

The question is, did Pontiac ship 10,000 (or more) SR blocks each year? Or were SR numbers picked at random. I just don't know at this point. But I'll keep looking!

Mike would like to know: Did the 455 ci or SD use a 60-80 psi pump spring that was problematic 1n the early 1970's that a mechanic helped the factory in testing and development due to a spring pressure issue, causing those Engines to fail early? " Not" the fuel being the actual cause of failure on those 455 ci Blocks.

[tekuhn]

Pictures of the caps: