Thread: I need some help...what's the diference between a big block and short block?

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I know almost nothing about engines, and I'm looking into buying a 350 block to rebuild. So what's the diference between a big block and short block...Thanks, Zak.

a big block and a short block, are not one in the same, they are two seperate things. a big block is simply a big block engine with large bores like 427 454 502, a short block is an engine block that has the internals installed, such as crank, rods, pistons, cam shaft. a short block can come in big and small block set ups, and also a 350 that you want to build is a small block. and now comes the term long block, it is a short block with the cylinder heads installed. hope this helps in you new hobby that will have you enjoying and hating your garage in ways youve never imagined.

Zak, You 've actually brought up two different subjects.

If you are talking about Chevrolet engines, there are two basic design types.

"Small block": an engine that was released in 1955 as a 265 cubic inch, then later was enlarged to 302, 307, 327, 350 and 406 cubic inch variations, of the same design.

"big block": a totally different design, the original showed up as the 348, 409, and 427 sizes, then was redesigned using a few of the same dimensions, and was made in sizes of 366, 396, 402, 427, and 454 cubic inches. Very few of the parts will interchange between the first and second versions.

On the subject of replacement engines for any make or model...

.."Short block" mean the basic engine, complete with crank, rods, pistons, and cam, but no cylinder heads.

"long block" means the basic engine, including the cylinder heads.


Looks like you got an answer from two people. :-)

Ditto to both previous responses. Don't get caught short buying a short block unless you're certain that is what you want. If you plan to use existing parts on your build then buying a short block can save you $$, otherwise you would want a long block or perhaps a "carb to pan" engine.

thanks for the responses. so what you're saying is that for what I want to do I need a long block? Oh and by the way, do yall know anything about rebuilding a Corvette L-98?

Hey, my 85 Corvette has an L-98 Tuned Port Injection 350 in it. Can you get any 350 small block and use it as a tuned port injection, or is the TPI engines a completely different block design?

If you have a good engine rebuild shop there, and I don't see why a city that size wouldn't, I would simply rebuild your old one, unless it's damaged beyond repair.

Ask the local racers who they would recommend. You will usually find that the best engine guys will be known by people who race.

My old engine runs great, I just need a project. I was thinking I would just get an engine like mine in case mine ever takes a dive, but mainly I just what to do this to learn how to rebuild an engine and become more familiar with how everything works.

Hello, Zak,

Glad to see you posting again! Did anything come of your '48 project?

If you're thinking of rebuilding with stock components, Northern Auto parts will sell you a very complete rebuild kit for a 350 for $170 ('69-'80) or $180 ('81 to '85). My brother has used them with no complaints, and if there's any complaining that needs doing, he's the boy that can do it.

They may be available for less gold somewhere else but I haven't seen them.


Jim

With football and school I haven't had time to go to my grandparents and mess with it.

Any 350 other than the LT or LS blocks will fork. Your reading assignment is here:

http://en.wikipedia.org/wiki/Chevrol...l-Block_engine

Thanks for the site. So any 350 will work for a TPI?

Have you done any reading about engine rebuilds? Back in the '80s, HP Books did one called "How To Hot Rod The Smallbock Chevy". (That's what you have.)

I am not expert in electronic injection, so before you try to use a different cam or compression ratio, I would consult someone with knowledge about these things.

I don't know what might be available today. If I were you, I would familiarize myself with the way 4-cycle engines operate, and how the Chevy's are put together.

ok. do you think for my first rebuild I should go with an older 350 that wouldn't be as complicated as a newer one? and once i get a better understanding of engines move on to a newer one?

Your car will be more valuable if it has "matching numbers". This means the original engine that came from the factory. This may be imortant to you down the road. I'm not sure where these are on that engine but if you have it rebuilt try to preserve these in some way if it becomes an issue. The engine builder will know.

Kitz