350 to 383 engines...got a question

[nickmm]

i got a 70 el camino with a 350 sbc and its bored .03 over...my question is if its bored that much does it make it a 383?? and can it be a 383 if its stroked? thanks

[MagicRat]

Originally Posted by nickmm

i got a 70 el camino with a 350 sbc and its bored .03 over...my question is if its bored that much does it make it a 383?? and can it be a 383 if its stroked? thanks

No. For a 350, an overbore of .030 adds about 5 cubic inches. So right now you have a 355.

A 383 engine is made by installing the crankshaft and rods from a 400 cid small block Chevy into a 350 block. (they made 400's back in the 1970's.)

The 400 crank has larger main bearing journals than a 350, so a machine shop must turn the 400 crank on a lathe to reduce the diameter of the 5 main bearing journals so it will fit.

BTW a 400 crank in a .030-bored 350 (like yours) will give you 388 cubes (not 383).

[nickmm]

Originally Posted by MagicRat

No. For a 350, an overbore of .030 adds about 5 cubic inches. So right now you have a 355.

A 383 engine is made by installing the crankshaft and rods from a 400 cid small block Chevy into a 350 block. (they made 400's back in the 1970's.)

The 400 crank has larger main bearing journals than a 350, so a machine shop must turn the 400 crank on a lathe to reduce the diameter of the 5 main bearing journals so it will fit.

BTW a 400 crank in a .030-bored 350 (like yours) will give you 388 cubes (not 383).

cool thanks. i knew that a new crank had to be added...hints the name 383 stroker....but i thought i heard a bored 350 without the 400 crank be called a 383 on other websites so i was kind of confused..thanks again

[MrPbody]

Nick,

It's not you that's confused. It's those refering to it as a 383 that are confused. Our hobby (performance and muscle cars) is LOADED with myth and superstition. A fundemental understanding of how an engine "works" is severely lacking. There are those that will argue that an overbore of .030" is a MAJOR modification (it is not). There are those that firmly believe one can "change" the displacement of a given engine by changing the connecting rods or pistons. Not so. The ONLY two parameters that affect actual displacement, are bore and stroke. NOTHING else.

I would recommend, rather than coming to sites like this to ask such basic questions, you find a good book that describes the engine and it's functions. Make sure it's an "engineering" book (like a text book) and not a magazine-based "article". Some of our BIGGEST headaches come from "journalists" not having a clue and making recommendations outside their knowledge base (usually based on "flavor of the month" aftermarket parts being "hawked" in their magazines).

Don't misunderstand this. We're more than happy to answer the questions. But if you educate yourself with the REAL information, you can fend off these guys without batting an eye! As a business owner and master engine builder, I like it better when my customers are better educated. It makes me look better 'cuz I know what I'm doing!

Jim