Other than emissions garbage that was added over the years, is there any real difference in the Olds 455’s? Say a 74 Delta 88 455 vs a 69 Cutlass 455.

 

Head geometry from the various versions, cams, and compression ratio influencing pistons.

 

The mounting hole for the clutch pivot ball was omitted in the later years. I think it’s a myth, but supposedly the earlier blocks had better metallurgy. Unless you need the pivot mount, any 455 block is going to be adequate for 95% of the Olds guys.

 

The metallurgy is a myth. Why would this ONLY apply to 455 blocks and not other Oldsmobile blocks?

To the OP's question, the big external difference, as noted, is the missing hole for the clutch Z-bar pivot ball on the FA blocks. Other than that, the blocks, cranks, rods are all interchangeable. Olds varied CR with different size piston dish, and obviously the cams changed depending on the year and application. Nearly all BBO heads will flow the same if you install the same size valves, except for the "J" casting heads used in the 1973-76 model years. Stock 4bbl intakes (even the aluminum W30 intakes) have pretty much the same runner design, with the exception of the Toronado intakes with the depressed carb for hood clearance. Exhaust manifolds go with the chassis that engine was installed in.

 

So I could buy a 70+ year block and put whatever pistons I wanted in it?

 

Pretty much what I said above:

 

This is a technical detail, but a 69 Cutlass would not have a 455. Prior to 1970 the 455 was used in the big cars. The only Cutlass to get the 455 was the Hurst Olds.

 

I did say I doubt there is any truth to the myth.

Anyone in readerland know WHERE the myth originated? Same with the solid main web 403 myth. Just curious, most rumors and myths have their origins with factual information. Curious if anyone knows where they started.

 

I'd like to know who first decided that headers don't fit Supremes...

 

I have a '73 Fa block that has the pivot stud hole. Removed it myself from a Custom Cruiser.
Was '73 the last year the blocks had the stud hole ?