Hello all, I've was told I had a 403 olds in my truck but after an extensive search this evening I found a 350 cast on the block- near the rear on the passenger side. Under the #1 plug I found a 3A which I guess are the heads, and under the plug next to it I found a GM8. Behind the oil fill tube I found a 16 cast. On the intake is 411990, which from my search are 400/455 EGR heads, and there was a D6CE next to it. Do I have smorgasbord type of engine? Are there other numbers to help me identify what I have? I don't know where else to find them.. thanks for any help

 

What do you see on the shelf NEXT to the oil fill tube? The 16 is the intake, not the block. It should read 557752. That would make sense with the 3A you found on the heads. That would make it a 77-80 350.

 

3A is a 1977 or newer 350 head. The intake casting number you listed is a 403 intake manifold however the 16 is for a 350. So one of the number is wrong. My guess would be a poorly cast or dirty 411880. If it was for a 400/455 it would not fit as it is wider than the motor. Next to the oil fill tube is a shelf where you will find another casting number for the block. If its 395558 its a 1968-1976 block. 557752 is a newer 350 block casting. less desireable for street perfomance builds due to their windowed main web design.

you can use this link or the oldswiki site...

http://oldsjunction.classicoldsmobile.com/oldsfaq/

hope that helps.

John

 

you guys have enlightened me, thanks! So it seems I have a 77-80 350 with the lightening webs?, and a 400-455 egr intake. The intake casting is very clear to be a 411990, the same area also had the d6ce. Looking lower definitely helped, I found a 557752 and a "big" 3B. I guess it's a 3b head? If I've got this right it should help as I get parts and such, I appreciate it!- Greg

 

It is impossible to use a 400/425/455 intake on a 350. It's too wide.
I think it's a 403 intake.

The block cast is 557752 3B and the heads are 3A.

 

Thanks for clarifying, that would probably explain why I was told it had a 403- the intake. Is it a pretty good engine for street use, just stay away from the mods? I'm thinking about freshening it up and changing the intake, anything I should be aware of?

 

yes, its a 403 intake. Either casting number is correct for a 403.

 

It's a great motor. Just don't make it 500 horsepower and spin it to 7 grand.
Beware of cracks in the exhaust ports on those 3A heads. I'd get them magnafluxed when you rebuild.

 

I was thinking about bolting up a set of headers, I do believe the passenger side manifold is cracked. Guess the extra heat on the engine(from cracked maifold) would be just enough to fry it? I just want something that runs good and doesn't leak..
On a different note, I've been trying to time this engine and the p.o. just had a distributor put in. If I hook up to #8 plug timing marks work, but if I hook up #1 plug the timing marks are 90 degrees away. If I try and time it by #1, I have to rotate the distributor 180 degrees to even get close and the engine starts to run crappy. Just to add, timed by #8 plug, it runs fairly smooth at idle and smooth running down the road. Is it possible they installed the distributor lined up with #8 cylinder instead of #1? It's weird to me and the only thing I can think is they put it in wrong...

 

BTW Randy, that's a sweet 442 in ur sig..

 

Most likely. since they are next to each other in the firing order it's likely they started at 8 (as 1) and worked around. In all reality the distributor doesn't care where #1 is as long as the entire firing order is correct. Me personally, I like things where they belong.

John

 

My buddy has a set of NOS 3A's he might want to sell (yes, that's right, brand new never used before 3A heads)...

 

thanks, that makes sense too! I've got a buddy that's going to help me put things right tomorrow- I like things as they should be, also. +1

 

thanks for the offer, but from what I've read searching, I think the 7a heads are the better replacement. Did I get this wrong? I dunno??

 

You would be correct. However you will need to drill out the head bolt holes to accept the larger head bolts. Except there isn't a whole lot you can do to compensate for the very large dog dish pistons in that motor.

John

 

Thanks. It's a "work in progress" for sure.

1970_442_007.jpg

newwheelsoncar_004.jpg


This one was taken right after I got the rims. The paint job was a few months old. It looks much better in the pics I think, but that's what I get for $500 (paint job).

 

Th3 73-79 pistons should be 14cc dish. Not too bad.
71-72 are the soup bowls. They reduced the compression in the pistons on those years.
In 73, they started using the giant #8 heads to reduce the compression instead of the piston dish.

 

All right just wanted to say "thanks" again, and update you guys as I couldn't have gotten here without the help. I got the timing worked out, it ended up being off by one tooth. So now the engine is running better, and I can get new parts as needed now that I know which engine and yr range I have. Much thanks! Greg