The Stovebolt Site Forums The Shop Area Engine Shop BIG Block Olds

Is there anything I should be wary about or know about an olds BIG block 350? Anything good? Anything Bad? Its bolted to a turbo 400, but could it be swapped for a SBC or a different BIG block (basically, how is it mounted)? Thanks much!

BOP engines only bolt up to the BOP transmissions. If you want to change to a Chevy engine, you'll have to change the trans too. The Olds 350 was a decent engine, good torque and all but a mild performance engine.
Scott

What does BOP stand for? The only logical thing that comes to mind is Buick/olds/pontiac (??) Decent engine is all that is needed. Thanks

Yes BOP stands for Buick/Olds/Pontiac. If you have a big block Olds engine it's a 455. They can be made into a high performance engine.

I have a big block olds in my 62 c10 shortbox. It fits really nice. cutlass headers work with out cutting and it will really haul the mail. 13.00 without tuning. It is a 425 olds from 1966. 365hp out of the factory. Olds motors make a TON of torque down low. My engine pulls extremely hard up to 5500. but thats all you need on the street. Just my two cents.

As far as mounting it goes - it will depend a lot on what it is going into.

Custom motor mounts usually fall into two categories: Chevy and ford. The predominant swap is the small block chevy, so consequently it is nearly the only custom motor mount out there. Fords are not nearly as common, so you can only find a few of those type of mounts.

If you want to swap this motor, you will likely need to fabricate the motor mounts for it.

I guess I don't understand all I think I know about GM engines. 350 ci engines have a small block...396, 427, 454's have a big block. Isn't this correct? There is no such animal as a 350 big block or a 454 small block...is this right??

While I'm foaming at the keyboard, must everything be "billet" and "crate motor".


Stuart.

I believe the 348, offered during the era of the 409, was a big block. They also made a small block 400cid. www.mortec.com has more information than you can shake a stick at for Chevy engines. Is there a similar site for BOP mills?

Here's a website for you.
http://www.442.com/oldsfaq/ofeng.htm#Engines
First, figure out what you have. Sadly, for a while GM put Chevy 350s in the Olds. If that's what you have, it will be like any 350.

The small block was made in several sizes from 265 to 400. Some crate engines have been sold with 406 and 427 cubes.

The big block was sold in sizes from 366 to 454. Crates are available up to 572, I believe.

BOP had their own engines, which were superior to the Chevy. Usually better head design and a block with higher nickel content, which made for a longer lasting engine. Their sizes were usually close to Chevy.

Brad,
I was in high school when the 409 came out. The 348 had a poor cube to hp ratio which the 409 improved on. These were both scalloped head engines, and I assume the block was BIG, not of the 265/283/327/350 ect size. In those "daze" the motors were called out by there cubic inches, not block size. So am I correct in my assumption that the only 350 made by GM has a small block?


Stuart.

Atomarc, I think you are correct. If not, someone will be along shortly to let us know. Chevy info is all on that mortec website if you want to spend the time looking.

I just gave a quick scan of the website Fred T suggests. It is chock full of good info for the Olds engines.

ArticCat, go there and read up. It explains that the only difference between the Olds BB and SB was the deck height, and it explains how to tell the difference looking at your engine.

AMC used to do something similar. Their V8 was all the same block, whether the diplacement was 290, 304, 343, 260, 390 or 401. I think I read somewhere once that there are a couple different deck heights for Chev BBs too. Maybe that's the difference between the 366 and the 427 and 454.

The Olds 350 was basically the same size as the 455 Olds,externally,thus,it was a big block Olds.same was true of the Pontiac 326 and the Buick 350 engine (not counting the corporate 350 used by all GM divisions and based on the Chevy engine).
Speed

The 455 Olds LOOKS the same as the 260/307/350/400 Olds engine, but it's 1" taller, and 1 1/2" wider than the other engines. I found that out the hard way trying to install a customer-supplied used engine.

The 500 Cadillac (early to mid-70's) is one of the best swaps, more powerful, and lighter weight than the Olds engines.
Jerry

-small block olds- have number designated heads. -big block olds- have letter designated heads. My motor mounts in my truck were very easy to build. trans sits on the torsion bar cross member. the rear motor mount cross member from the 235 had to be removed. the engine looks factory in the truck except for the headers. manifolds would work but not on my truck wich sees drag strip time. If your going to put in a olds engine go to www.mondellotwister.com and read up on the oiling system of the olds engine. you'll need to beef it up if you plan on buzzin one higher than 5000rpm.

Thanks guys! Lots of great info.

I had a olds with a big block 350 in it, or at I thought it was when I owned it in the mid 80s. It was certainly larger in size than the 350 chevy engine I had in a monte carlo I owned at the same time.

What I wondered then and now is if both engines has 350 cubic inches of displacement, based upon the diameter and length of the cylinders combined with the combustion chamber in the head, what difference does it make to me whether it is a big block or small block?

The things that come to my mind are durability, perhaps a big block, being bigger, will hold up to more?

If availability of parts and durability are your interests, there are small block chevy 350's out there that'll be easier to build and probably just as durable.

The term "big" and "small" block is a Chevrolet nickname for there engines. It doesn't really apply to the BOP cars. I know a 455 is a direct bolt in for the 350, so the external dimensions of the blocks are very close to the same.
Scott

Pontiacs where considered " Large Journal " or " Small Journal " A 326 thur 455 take the same bellhousing.