Olds Engine Question 403 vs 455

[G V Gordon]

I went to look at a '76 Olds 88 with 53K that has been setting in a shed for three years, last tagged in 1995. Couldn't get in front to pop the hood but am hoping it's the big V8. Was the 403 just a different model of the 455 or was it based on the smaller block. Or was it a bastard and don't interchange with anything.

[Fat Hack]

The 403 was based on the 260-307-350 block, the 425 and 455 were the "big block" Olds mills...

Taller deck height and wider intake mainly, but similar in design.

See my Olds V8 post for an overview of the "small block" Olds V8s.

[G V Gordon]

Thanks Hack,
This is a nice old original car that would clean up very nice but you never know what your gonna run into with a car that has set that long. Price is right though. I'll sleep on it.
Thanks again,
George

[Fat Hack]

A 76 car will PROBABLY have either a 350 or a 455 in it. Either one is good, but I really love them "small block" Olds V8s...owned several and they will run forever!!

[38Chevy454]

403 is a big bore short stroke design. Low-deck height like the 350. One of the under-rated engines I would say as for potential. Big bore short stroke is always good for power, think of 302 and 327 SBC's , or 289 and 302 SBF's as similar design. Too bad the 403 was always a smog motor or mullet engine (used in many of the late 70's Trans-Ams).

Like Hack said, may get lucky and get one of the last 455's built. Or the 350 or 403. Either way if the car is nice and price is right, sounds like a good deal.

[ESnacky6]

Hey Fat Hack, where's your post about small block Olds V8s..??

is it a recent post, or something that you'll be posting soon..?

Thanks..!!

[choprods]

THE 403 WAS ALSO IN BUICK ELECTRA TOO THEY RUN RESPECTABLE=THE EARLIER 455 WAS BETTER THAN SAY 76 OR SO WAS.

[Anderson]

Don't put any money into a 403. It's a good runner, but don't try to make a performance engine out of it. It'd be a waste of time...it's got windowed main webs which will crack. The motor has the numbers to be a badass, high-revving screamer, but it lacks the bottom end to support it. Also, it's got siamesed cylinder walls I believe, meaning if it's .60 over, the block is trash. - My two cents.

But as mentioned above, it's probably not a 403. Hope it's a 455, torque monster!!! Could be a 350, which is a great motor too with tons of potential. I use one daily.

[slammed]

'76 was the last year for the 455. As mentioned before it will be 350 or 455.Great long lasting motor's.Good hunting.