Thread: Olds 425 rocket engine

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I was just wondering if a 425 rocket engine is the same physical size as the Small block 350?

I was just wondering this because i always see the late 70's oldsmobiles that have the 425 rocket for like 400- 500 bucks.

OK, let me expand upon techs "NO". The 425 and 455 are Big block oldsmobiles. About 4 inches taller, 3 inches wider and somewhere around 150-250 lbs heavier with steel intake. Also, I believe your mistaken. The 425 ended production back in the late 60's, and was replaced with the 455. If Im not mistaken, the engine your looking at is the 403. It is the same size as the 350, and will swap over. However, this engine requires special care, as its a Large bore SB, and 99% of the time has webbed mains. Hope this helps.

This is very good information to know as is all information provided on this site. What does "Webbed Mains" mean.