425's in a 1965 442 - Revisited

"Destroked"

Kinda hard to do when they both used the same crank (and thus had the same stroke)...

The 400 DID have a smaller bore than the 425, however, 4.000" vs. 4.125".

As for the 425 in the 442 rumor that won't die, no one who claims this is true has yet produced a scrap of factory documentation or other proof.

I hope the 425 rumor never dies, and lots of things went on in the 60`s cars that can`t be documented. I`d have to erase a lot of memories working on these cars back then if the only things that could be worked on had to be on the build sheet. Cookie cutter they weren't !!!

................................ BLACK

Just for the record....... I'm not the first to use the term destroked. It's been in articles detailing the 442's for years. I know you've read every article that I have JOE, so why feel the need to comment on this one. These are only three clips from different articles describing it as DESTROKED. Feel free to search them on the internet and let them have it too!


By the 1965 model year, Oldsmobile had the answer, by adding 35 additional horsepower. The General Motors brass were swayed by the success of the Pontiac GTO, so they relented on their decision to keep big blocks out of the mid-size cars. The 65 Cutlass 442 could now be equipped with a de-stroked version of Oldsmobile's monster Stage II 425 Rocket V8. Apparently modified to keep within the revised GM bounds restricting mid-size cars to engines of 400 cubic inches or less, this new 442 powerplant measured out at 400 cubic inches on the nose. Using what Hot Rod magazine described as a "moderate" 10.25:1 compression ratio, the 442's Rocket engine produced a claimed 345 horsepower and an amazing 440 pound-feet of peak torque at 3200 rpm. There's no substitute for cubes.

Designed for heavy-duty use, the engine offered such hot rod parts as forged steel crankshaft and connecting rods, light, stamped steel rocker arms with tubular pushrods, plus 2.0-inch intake and 1.625-inch exhaust valves. All of this good stuff, to use the words of Hot Rod, "contributed to vigorous and long-lasting health."
In 1965, Oldsmobile continued the 442 option on the Cutlass and the F-85. In this model year, the 442 designation changed definitions. It was now a 400 cubic inch engine. a 4 barrel carburetor with dual exhausts Oldsmobile used the 425 cubic inch power plant from their full size automobile platform. Oldsmobile destroked this engine from 425 cubic inches down to 400 cubic inches for the 442 option. This was done because the General Motors management stated in a memo, that any intermediate automotive platform vehicle could not exceed 400 cubic inches.

Also for 1965, GM raised the displacement ceiling on intermediates to 400 cubic inches. Olds destroked and debored its new 425-cid big-car V-8 to create a hot 400-cid V-8 exclusively for the 1965 Oldsmobile Cutlass 4-4-2. With this change, the name now meant 400 cubes, four-barrel carburetor, and dual exhausts.

The 1965 Oldsmobile Cutlass 4-4-2's horsepower increased by 35, to 345, and torque expanded by 85 lb-ft, to 440. Peak power now came at 4800 rpm, not 5200, and peak torque was on tap at just 3200 rpm, 400 rpm lower than before.

Absolutely!

de stroke in de motor is de same