Spinning the Wheel of 455 Mystery

Picked this guy up for cheap this morning. Not that I would have paid any good money for it, it's a classic "so and so rebuilt it xyz years ago and it didn't have many miles on the build when pulled". It was also a "1970", which the block #1241735 tells me is not the case. No two letter codes to be found, so decks might have been cut on, indicating rebuild truth. All I know is the block seems to be pontiac blue, the heads are black, the thing turns free, and I don't see any big holes in it. I'll take bunches of pictures when I get it in the shop and tear into it, I'm sure all of you know just how many possibilities I could find in store! (Not all of those are good ones either )

 

It looks like EGR or A.I.R. motor. Strange looking thermostat housing.

 

Googling says the block is 72-75 so you are probably correct, but it does have a non-AIR intake on it, or at least that's how I understand it. It lacks the bosses that run parallel to the valve covers on the sides of the manifold

 

Somebody's been into that motor. I bet you find all sorts of interesting things.

 

I'm guessing it's a '75-'76 engine. Traces of blue paint, HEI and later valve covers, and the EGR intake. The thermostat housing looks like it's from a V6.

 

Yep. Like, spiders and snakes...

 

I think your right on the money.

 

Popped a valve cover, I'd say it's been rebuilt for sure, but the question of how well remains for now. It's hospital clean in there.

What's the deal with this head casting? All I can find is "72-76", surely they didn't use the same casting number on both the early style head and the late open chamber head?


EDIT: it appears these are 75-76 heads, so big open chambers. Bring on the 7.8:1 compression. I guess I'll start looking for some heads lol

 

I don't doubt this, actually sort of expect it myself, but the blue on this engine has been done after the fact. In spots I can wipe the dust off it has almost a metallic look to it, like old Pontiac engine color.

 

bolt it in and go

 

Looks like a 70 divorced choke.

 

No that's the 75-76 hot air choke. A 70 intake will not work with those heads. The exhaust crossover would be exposed.

 

Do you see an air rail on the intake?

 

There are no raised rails on the intake but it has the head casting for 75-76 so I assune the worst regardless

 

You can always get an edelbrock performance intake.
They bolt on my 73heads
Have fun
Nuttin like a big block!!

 

I have two sets of those heads 8322 Off engine yes open chamber. Wonder what you would get with shaved heads and block. 9.5:1 wouldn’t be to bad.

 

75-76 455 didn't have A.I.R... so no. Plus the blocked egr valve is clearly visible at the back of the intake. Also there is a piece of rubber hose over the choke tube with a bolt stuck in it.....

 

I understand correctly that a performer will not bolt on these heads, even if through some miracle it does turn out to have some compression?

 

I must have been thinking of the early iron intake not fitting or something. I'm sure the heads will have to go anyways. Chamber shape aside, the only way I can see the people who were in it getting any kind of compression is with a flat top piston, which I do not expect to find. It was around 10 years ago when it was supposedly done, so I'm not sure what piston options were available at the time.