I am looking for a 455 long block, Oil pan to 4bb air cleaner would be great, unless I can use some of the 260 brackets. It needs to have the Z bar holes. Can these be found with out having a big surprise? Mostly I am worried about cracked cylinder heads but is there any other concerns to buying a "good core motor"? Fa engines probably will not work so my next questions will not matter. Did Oldsmobile drop compression in the 70s? When was EGR added? It will be going in a 1977 442 and unless the owner gets classic car insurance it will need to pass emissions. it will be a driver/cruiser.

 

Compression dropped in 1971, and EGR was introduced in 1973.

I don't know when the blocks stopped being drilled for the ball pivot, but I have a disassembled 1972 455 in the garage that was from a full-size car and the block is drilled and tapped for it.

 

1968-1970 engines are the best cores because of the heads, and aside from the super-low profile intake and unique oil pan on the Toronado engines, they are usually the best core engines. Upgrade the intake and swap to a standard oil pan or Canton oil pan if there is money. What type of emissions does it have to pass?

 

CO and HC at cruise and at idle. It may also have to pass a visual inspection for catalytic converter(s) adding to the expense of exhaust.

 

I had to go through that with my car for years, and Bob Powers gave me recommendations on how to reduce emissions, which ended up being very successful. AZ finally changed the emissions regulations and I am now able to register the 71 as emissions exempt.

 

Care to share the tricks?

 

• Decrease the initial timing (which with the HEI will also limit the mechanical timing at speed on the rollers). I dropped the initial from 18º to 10º.
• Disconnect the vacuum advance completely. This is essentially what GM did by going to a ported vacuum source.
• Use low octane gasoline with alcohol added. I would mix 87 octane with E-85 for around 25% alcohol content.
• Over-inflate the rear tires to reduce rolling resistance. I stopped doing this as the above items resulted in super-clean HC and CO numbers.