First off I’m not an Oldsmobile expert. Some guys are. However I’m pretty damn good at tuning and finding problems. This guy (a true blue ford guy) says he’s got a 455 built to ‘70 W30 specks. He’s got a big fat bill to prove it. Says it’s just not running right, should have more spunk. Here’s what I found - 12” not 14” 395558 2 That’s not a 455 it’s a 350 right? I know 99% I’m right but need some moral support before I tell the guy this and light that fuse. It’s gonna be a shit storm! Maybe I’m full of shit, maybe someone is pulling my leg, maybe someone really fucked this guy.
I can't add much based on casting numbers but I can tell you the intake manifolds do not interchange between 455 and 350. Wish I could be more specific. Valve covers however do cross over.
68-74 350 block. Depending on the pistons etc, it could be a W31 with that casting from 68-70. I would say he got hosed. His bad for not verifying it before he bought it. I guess ALL Olds motors are 455's like all SBC are froma Corvette eh?
So first, he bought a tired engine that he was told was a 455. (?) And second, he turned it over to someone else to build it to 455 W30 specs. (?) And when that builder guy was done, he called the owner and said. "Come pick up your 455 W30". (?) Am I reading that right?
yes that's a 350 or a 403, if it has a eyebrow cut in the balancer it is a 403. if i remember right some had the size cast on the side of the block.
I’ve got to get more info and look at the bill but so far that’s how I’m getting the story. He thinks he’s got the Mac Daddy Olds 455 ‘70 w30 “clone” I’ll be making the phone call this evening.
Do I see Offenhauser RPM cast on the intake? If so it will also have it's Offenhauser part number on it. Look it up, end of question.
Look at front of head by plug and see if head has a cast letter (BBO) or near center exh. port for number (SBO).
2 issues here if the guy was sold a 455 build and has a 350. 1. The owner assumed he had a 455. I’m a strange person, I look up casting numbers, stamping and vins. It’s part of the fun of messing with old stuff. Also helps when ordering parts. 2. An engine builder sold a guy pig in a poke. (southern term for getting screwed)
I guess this is common with olds? My buddy was raving about his new impala with a 455 in it. I went over there and it was stamped 5.7 on the front. He was pissed it was a 350
i'm a olds man and have never seen anything like that. small blocks have numbers and big blocks have letters to identify the heads. the pic posted you can see the bottom of the intake is about even with the top of the timing cover, the big block olds sets about a inch higher. also in the valley between the intake and timing cover the big block has a rib that runs from the front of block at the lifter valley to the back of the timing cover face where the small block doesn't.
If the owner was a true blue Ford guy, he would know not to trust casting numbers. Measure and verify.
They're actually pretty easy to spot at a glance if you're used to seeing them. I've had both. It's like seeing a 241 Hemi and a 392 hemi...similar but different. The 455 is a lot wider. The last 350 Olds I had was a W-31 Hurst olds. It was a smogger 1975 and it was a DOG! But I had a 69 Olds 455 in a huge delta 88 Royale coupe that was a torque monster. It was impressive but it actually had some compression to it. Would zip up to 120 MPH with the Q'jet howling! Your buddy may have been told his engine was built to w-31 specs which would have been a 350 Olds engine.
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