[Gary H]

Originally Posted by kingbuzzo

If it's a block from a big car, does that lessen it's worth somehow?

Does it have weaker webbing or less nickel than the performance lines or is it the same difference?

No, It's the same identical casting as any other block that year. Pontiac used the same casting number for all 71' - 74' 455 blocks except the SD blocks. The 73' - 74' 455 SD blocks had multiple different features that the standard block didn't have.

[74Grandville]

I’ve owned a 70 455 YH. It had 2bolt main caps


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[Kenth]

I can´t swear it´s factory, but the workhorse 1970 YH 455 i´m using in my Judge had the 4-bolt main caps when i found it 25 years ago.

FWIW