I HAVE A 455 OLDS IN MY 33 ESSEX STREET ROD.  SAID TO HAVE COME FROM THE OLDS LAB AS A BACKUP ENGINE FOR THE INDY PACE CAR
FRONT OF BLOCK NUMBERS  398021
ABOVE RIGHT EXHAUST 411   783
BACK OF BLOCK AND NOT FOR SURE   2260
 wHAT DO I REALLY HAVE HERE????  

Sure the front of the block isn't 396021??  In that case it'd be for sure a 455 block.

The heads should have a big "J" stamped on the cylinder head...front of the motor for the driver's side.  Those are smog era heads, and are supposed to be very restrictive.  Combustion chamber CC will be in the 80-82 cc range.

Those heads also put the motor in the 1973-1976 range.

Hope that helps.  

IM NEEDING HELP I JUST GOT A 1985 OLDSMOBILE DELTA 88. I GOT IT JUST TO JUNK BUT THE MOTOR RUNS REALLY GOOD BUT I DONT KNOW WHAT IT IS I KNOW ITS A BIG BLOCK OLDS THATS JUST ABOUT IT BUT I DO HAVE THE NUMBERS OFF THE FRONT OF THE BLOCK RIGHT IN FRONT OF THE WATER PUMP AND THE TIMING COVER ITS 557265 4B. IF YOU CAN HELP PLEASE DO  

Its not a big block.  Its a 1977-79 403.  Thats a small block.  Windowed mains too...which is a bad thing.  Don't plan on making too much power with it unless you beef up that bottom end quite a bit.  

403's can be solid little street motors without doing anything to the bottom end.  Drill out the headbolt holes on an early set of 350 heads and swap in a cam and intake and you'll have enough grunt to move that land barge.

-Joe  

Guess I should clearify, as many people have different metrics for power.  I'm talking going anywhere near 450-500 HP, you'll need to beef up that bottom end...or you'll be driving a time bomb.  Nothing saying you cant make a solid 300-350 HP street machine out of it...and still have it last a long time.  

The 403 is widely overlooked as a performance engine.  They can be stout little buggers and a decent engine in a street strip car.  But for an all out drag engine the bottom end will need some help.  I've got one in my garage right not but am unsure what to do with it.  I've got an '86 Cutlass that is pretty rough to be turned into a daily/cruiser so I may go budget strip car.  Debating 455/403/350, the 425 I have is going in my '69 some day.  A 455 would give me nice numbers with stock internals and I've got a couple sets of C heads...but a nice 350 with a small shot could be fun as well.  The 403 was 40 bucks and might find it's way in there...



-Joe  

i always have been told that the 403 was a big block the 350 olds was and the 400  

ive always thoght that a 403 was a big block is it or not it looks just like a 455  

Olds big blocks are the 400-425-455.  Common small blocks are 307-330-350-403.  It is not a deal like Pontiac where they were all one block.

Your block has a 1" shorter deck height than a big block.  That accounts for a more narrow motor, as well as a shorter motor.  Other than that they appear very similar to each other.  

69Rocket-Joe:
The 403 is widely overlooked as a performance engine.  They can be stout little buggers and a decent engine in a street strip car.  But for an all out drag engine the bottom end will need some help.  I've got one in my garage right not but am unsure what to do with it.  I've got an '86 Cutlass that is pretty rough to be turned into a daily/cruiser so I may go budget strip car.  Debating 455/403/350, the 425 I have is going in my '69 some day.  A 455 would give me nice numbers with stock internals and I've got a couple sets of C heads...but a nice 350 with a small shot could be fun as well.  The 403 was 40 bucks and might find it's way in there...



-Joe

For 40 bucks...a 403 is WELL worth it.

My projects include a 68 Cutlass with an Olds 350...LOTS of work done to it.  And an 85 Delta 88 that I'm swapping a 425 into.

Olds guys just seem to love this forum    

CSIROC,  Yeah I have a '69 Cutlass S that I want to do the 425 with a 5speed swap.  That would be a fun high reving big block!  I'm also trying to do a 455 swap into an '88 Silverado and keep the TBI setup.  If I get the bugs worked out in that I'd like to do an Olds 350 into my '92 3/4 ton Silverado.  Then there is the '86 Cutlass that is too rough to turn back on the road but too nice to sacrifice to the stock car gods.  I am thinking I am going to gut it and turn it into a strip car.  

Yes I have too many projects...and all will be Olds powered someday!  

-Joe  

I'm looking to put an olds 455 in an 85 trans am. bolt to a 700 r4, would it work and what would i need to alter to make it work?  

Adapter plate for the 700-R4.  You'd be better off using a 200-4R and beefing that up...but if you already have the 700-R4 no sense in buying a new transmission.

You'll have to change your motor mounts...and you'll almost definitely have clearance problems somewhere.  Might look for a toronado intake...they are a bit shorter than other intakes.

Oh...and you'll end up replacing that rear end at some point.  Whether you do it now or when it breaks is up to you.  

Well nathan44 I hope your good friends with Jesse James & the cast of monster garage because that is what it is going to take. The 455 olds is wider & quite a bit heavier than your smallblock. You might have to delete your airconditioning if not already out, relocate or get a smaller powerbrake booster. You will have oilpan & hood clearance problems.You will need custom fabricated headers$$$$. Heavy duty front springs to compensate for the heavy engine, custom motor mounts. You may also have to move or alter your steering linkage & shaft. Unless you upgrade your stock 700r4 & rearend, its not if they go out its when, they just won't hold up to that engines torque. Save the money on this headache & put it in a SBC.