Moe

I am rebuilding my 350 rocket from my 72 cutlass. What can I increase the CID to?

I saw this comment as an answer on wiki answers...

"For instance, Oldsmobile used the same block for cubic inches ranging from 260 to 455"

Is it even possible, or is the post someone that doesn't know what they are talking about? I find it hard to believe.

bccan

I'll start since I happened upon this. Most important thing to remember is consider what you are looking for - something that runs on 87 or 89 that will purr like a kitten, might bark the tires if you if you catch it right and wanna get ice cream on a nice night, maybe hit some car shows - a driver. Other end for a "typical" 350 build would be something that can put down a low/mid 13 sec pass @ the strip but is still driveable on the street. Most are a little in between, some are off the chart @ either end.

Cubic inches in a conventional 350 build will be limited to just over 370 - that is a 4.125 bore w/ 3.5 stroke. Most early 350 blocks & cranks can hit these specs but need to be qualified on an individual basis. Even that type build will need more than "basic" machine work & parts but isn't complicated. If you are looking more toward the moderate end of the performance scale, you don't even need to go that far.

If you have a 72 350 in the car, you more than likely will need to change pistons to a smaller dish volume to increase compression ratio, rebuild the heads - upgrades can be done, more $$, typically more performance. Cam appropriately and gear the car accordingly & you will have a nice driver that can give satisfying acceleration.

If you want more, then you might start thinking about going into a big block - they are different from small block, deck height is taller but many components fit either family. Big blocks run 400 - 455 ci. The advantage to bigger displacement is you can maintain engine manners & drivability while increasing performance.

You will get many answers on this subject, I'll edit & post a link to a debate over 350 "drivability" discussion.

https://classicoldsmobile.com/forums...y-rebuild.html

IMO the best thing is to set a "use & performance" goal, get together w/ an Olds engine builder specialist (you will see names posted many times) & have them guide you at least through a combination & strategy and supply you w/ parts. If there is one that makes geographic sense, have them do the machine work too.

Check the FOR SALE sections on some of the Olds sights, there are occasionally complete engines or components for very reasonable $$ that you might consider.

http://www.oldspower.com/vb/showthread.php?t=53188 - Probably gone...but good example.

http://www.realoldspower.com/phpBB2/...er=asc&start=0 - Gone too, but another example.

Give more info & you will get more feedback - confirm engine, trans, rear ratio, what you want out of it & where you are located.

Good Luck w/ your adventure

bccan

TTT for Moe - this needs to be where people will see it & get some traffic & additional viewpoints.

joe_padavano

Which is a perfect example of why you shouldn't believe Wiki Answers.

There are two different engine block families for the second gen Olds V8. The short deck (popularly known as "small block") built in displacements from 260 to 403 cu in and the tall deck ("big block") built in displacements from 400 to 455 cu in. Many internal parts swap between the two, but many don't.

As for increasing your displacement, you cannot build a 455 from a 350 gas motor (I'm excluding DX block custom built motors here). You cannot even build a 403 from a 350 since the 403 block has siamesed cylinders due to it's large bore. All small block Olds motors have the same 3.385" stroke, so there is no easy way to increase stroke short of a custom offset ground crank.

The bottom line is that you can pour a lot of money into custom parts to increase the displacement of your 350, or you can spend a couple of hundred bucks and get a 455 core to build instead.

507OLDS

Offset grind the factory crank,& leave it with small journal SBC rod journal sizes.You can easily do a 3.50" stroke,but I have done some with 3.75",depending on how nice the crank core is.Put the longest SBC rod in there that you can find,& a nice,lightweight,short piston.You will have one stout SBO. Contact Bill at BTR Performance.I think he can offer a 375" kit or assembly.He has done a few with some great success.I believe his 375" kits have a 3.500" stroke.