AlmightlyLoaf

I have a 455ci engine that I'm not sure about.

I think it's from a 1970-1972 Oldsmobile due to the engine stamp - 396021F.

Any ideas?

MDchanic

What's the VIN-derivative?



- Eric

joe_padavano

Welcome. That casting number was used for more years than just 1970-72. As Eric points out, the VIN derivative stamp will tell you the exact model year of the BLOCK. Other parts are bolt-on and may or may not be original to that block. The Pontiac blue paint needs to go, also...

joe_padavano

AlmightlyLoaf

It was a little bit hard getting to and a tad blurry, but I believe it's 31M40941 and the last digit is blurred. I think either a 3 or 5.

AlmightlyLoaf

I was a bit confused on the color myself. It was rebuilt about 10 years ago and I'm not sure if they sprayed it this color or if some 455s came out like this. I thought these only came in a deeper, metallic blue although I've been told otherwise.

Side by side, it almost looks exactly the same as my father's 1976 Pontiac 455.

Octania

31M
3 = Olds
_1 = 1971
__M = Michigan [Lansing] car assembly plant

400,000+ VIN tends to indicate a Toronado motor but the intake does not look Toronado. What is the intake casting ID letter in the depression aft of thermostat and/or 6-digit CN aft of carb?

Letter on the corner of the head should be a "G" for 1971 455's

Oil fill tube number should be 1xxxxxx, where x is any digit 0-9. Again the 1 is for 1971 model year.

joe_padavano

Actually, I think in 1971, the Lansing-built cars started at 100001 for A-bodies, 400001 for full size, and 700001 for Toros. Don't have my 1971 CSM here at the office, however.

AlmightlyLoaf

I couldn't find any number on the oil tube.

The letter on the intake to the right of the thermostat is "L".

The Rochester carb has a "remanufactured" tin label. It was bought new when the engine was rebuilt and not original.

The car has J heads although I'm not sure if they are original to the car. They were taken apart and rebuilt with aftermarket valves.

Octania

L intake sounds about right for a 71 Big Car 455

J heads are 73-76 issue, fine for most purposes.

Any other concerns with this powerplant?

AlmightlyLoaf

Any ideas on what specific model this block would come from (Delta, Toronado, Cutlass, etc?)

joe_padavano

The 4xxxxx serial number would suggest it was born in a full size 1971 Olds (Eighty Eight or Ninety Eight). That's really kind of irrelevant, as all 1971 motors had soup-bowl sized dishes in the pistons for 8.5:1 CR. The J heads tell us the engine's been worked on, so you have no idea what else was done to it.

AlmightlyLoaf

Yeah, I think it's a bit of a mix of Oldsmobile engines. Sadly, I don't have the exact information on the engine when it was rebuilt so it's a mystery to me.

Thank you for all of your help everyone. You guys really know your stuff.