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Discussion Starter #1
Hi Guys- need some help. I have a 1968 GTO that was built in Fremont. When I purchased the car, the original motor was included in the deal. 9790071 YS. I have that motor on a stand preparing for rebuild. The car came with a running motor in it. Here’s the catch: it’s a block code 9799914 YD. I have the Pontiac casting # book and can’t find that motor. It’s currently got the #16 heads and 4bbl intake from the original motor on it. Is this block a ghost? I’m pretty sure it’s a 70 casting.
 

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Discussion Starter #3
I get it that you’re going by memory but I can’t find it anywhere. What makes you sure?
 

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Discussion Starter #5
After going through the Pontiac casting # book, 9799914 is a 1970 casting. I see a couple RAIII engines in Firebird and GTO with that casting # and 4 bolt main caps. Those are only in California engines which this engine is. ( Z code) I see lots of Grand Prix’s, Tempest, and Catalina’s with that casting # and 2bolt mains.
 

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Discussion Starter #6
If casting # 9799914 was used for 1970 RAIII engines with 4-bolt mains, does that mean all # 9799914 castings are drilled and tapped for 4-bolt mains? This motor might be worth something.
 

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Lots of Pontiac engines were drilled & tapped for 4-bolt caps, but came with 2-boit caps.

All the '70-'74 455's I built to race were that way.

If you run 2-bolt caps, the webs would be stronger if those extra holes were not drilled.

Some buy 4-bolt caps & have the block line honed or bored.

Some recommend putting bolts in the empty holes, to add a little strength, I suppose. I never had any block problems, at the 400hp/500 torque level.
 
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