Topic: 403 olds or a 350 need some help

[billymadison]

I took my 79 trans am to a mechainic today to fix some leaks. I was also told by the mechanic today that my engine was a small block 350, when I thought it was a old 403. Even though my engine has the oil filler neck at the front of the engine, head code 4a, and at the top of the engine behind the oil filler it has  the numbers 5572*** 4B. I told him all that and he said the only way you can find out if it is or not is by the engine stamp inside the block. He said the stamps on the outside of the block doesnt mean anything even with the neck at the front of the engine. Is any of that what he said true, or does it sound like I have a old 403.  Whats the difference between the 350 and the olds 403, does the 350 have a oil filler at the front of the engine also. What do I need to look for.




here are some pics of it




thanks

[Hitman]

Yes, the 350 looks pretty much the same as the 403.  Infact, to get better performance out of an Olds 403, people say you can put on the 350 heads.

350 engine:


Olds 403:

[Rick]

It's definitely an OLDSMOBILE engine.  From your original post I thought the mechanic was saying it was a CHEVY 350 (that's the SBC reference -- Small Block Chevy).  To determine whether it's actually an Olds 350 or a Olds 403 you'll have to check the engine numbers.  SirLDragon has posted a picture that says where those numbers are found -- they are on the driver's side of the engine right under the head.  That will tell you for sure which displacement you have -- remember, in cars that were made that long ago sometimes people swap engines for different sizes.

[Joker (§ir£Ğragon)]

Actually the number that would tell what engine it is you already posted. The one next to the tube. The 4B at the end indicates a 403. See your other thread for the rest of my thoughts. I don't think I should go off on a rant again.

[billymadison]

thanks guys for the help,I really appreciate it. I think you are right about him being a idiot.

[Albert]

Sorry about to get in here. "Yes, the 350 looks pretty much the same as the 403.  Infact, to get better performance out of an Olds 403, people say you can put on the 350 heads."
If you do that, is there others things to change also, or it will bolt on like that.
(its because, i can buy a 350 olds at the moment from somebady i now, for a very interesting price, it had heads 4A on it)

Can plaese somebody tell me that of it works and if there other things to do as well.

Regards Albert

[oldskoolubr]

Ok The 403 actually has a 403 Number stamped in the BLOCK.  And like the gentleman said above the number on the front is the indicator as well!  No disputing the facts.  As far as heads I am in the process of adding a set of #6 or #7s now to up the compression, I am just afraid I will find too much wear in the cylinder walls and have to rebuild it?!  :/  Good Luck!

[Mongo]

oldskoolubr,  This thread is over three years old.

[Trans am Oz]

He's just trying to catch up

[oldskoolubr]

^Ya what he said!

[Mongo]

LOL!

[ShakerBreaker]

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