So I bought a "new" 400sbc engine as a spare while I rebuild my current engine....
It's a '817 2-bolt supposedly been "re-worked" but the seller was clueless as to what has been done to it, it's clean and been painted black. I pulled valve covered off and saw the classic 333882 heads so pretty clear those are bone stock I didn't notice any obvious spring upgrades, or rocker arm upgrades. So here's what I need help with:
1- how can I determine what rods are in it? I have the oil pan off.
2- how can I figure out what pistons are in it? Any way I can look in a certain place for some numbers or something?
3- I know the heads are '882 and they were '76cc chambers but any way I can figure out the combustion ratio without pulling heads? Or maybe measure the valves?

I want to see how much I can identify about this engine without pulling it completely apart. It's purpose is to be a temporary engine to run while I spend months if not years rebuilding the engine I currently have.
But I am tempted to throw a quick cam in it or even buy some good heads for my current engine but run them on this in the mean time (my current engine is a '509 casting 400 with vortec heads but needs to be bored etc)

So any "engine" guys out there to help me out with some advice or input?


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****udate I did some digging in the bottom
End with a flashlight looks like crank is Stock and with a rusty tape measure rods spear to be stock 5.5 and have the 1,2,3 etc stamped on the rod ends and rod caps suggesting stock. Also istons have "GM" and the #8 on the backside. Screams stock to me
Any thoughts?
I'm fine if it's stock means I get a blank canvas for dreaming lol




Update:



Numbers on caps





Caps

 

not sure if you can tell unless you can find some part numbers on them but i doubt you will. With out removing the heads best you can get is a guess especially without knowing what pistons are in it.

 

How about I see there any indicating numbers or castings on stock pistons that way I can at least figure out if they are aftermarket?
I also read somewhere that the 882 castings on 400's had bigger valves than 350's anyone know if this is true?

 

same intake with 1.60 exhaust although totally meaningless due to the fact heads are junk

 

You should be able to get a bore scope into the spark plug hole and see if the pistons are dished, or flat and how many valve reliefs. USB cameras are dirt cheap on ebay.

 

If you can get your hands on a borescope, you can remove a spark plug and look at the top of the piston. See if it's a flat top or a dished piston.





Identifying the piston will give you more of an idea what engine you have and if it's worth changing the cam at this point.

Good luck... GUSTO

 

A decent cam, edelbrock intake, holley 650 or so , set of headers and that engine will wake right up. Even with the stock heads , just might surprise ya.

 

I ran this exact setup for a few years minus the cam on my '509 400sbc
Any suggestions on cams for the stock crappy '882 heads?
The vortec heads got me spoiled but still only have stock cam

 

****udate I did some digging in the bottom
End with a flashlight looks like crank is Stock and with a rusty tape measure rods spear to be stock 5.5 and have the 1,2,3 etc stamped on the rod ends and rod caps suggesting stock. Also istons have "GM" and the #8 on the backside. Screams stock to me
Any thoughts?
I'm fine if it's stock means I get a blank canvas for dreaming lol

 

GM did not stamp numbers on the rod ends and caps. That means someone did a rebuild.

 

It also appears the nylon collar between the distributor and the oil pump is cracked. May as well drop the pump and replace the collar while the pan is off. Most here recommend using a metal collar instead of the typical nylon one.

Good luck with the project... GUSTO

 

Rod ends have no stamping it's just the sides of the part where it mates with its own cap they have sequential numbers front to back 1-8 you're sure that's not stock? Seems pretty factory to me but I don't know much.

Also caps have stamping numbers and "GM" why would someone replace caps with same GM wouldn't the "GM" be a sign that the caps are original?
Also pistons have "gm" stamped underneath just above rod connecting points
Rods appear to be 5.5" which I've never known Anyone to replace 400 rods with 5.5 I've always though people upgrade to 5.7 or 6
All the bottom end seems to be GM parts I would expect a rebuild to include aftermarket like scat eagle etc. am I wrong to think this way? Are there direct GM rebuild parts available maybe back in the day say 10 years ago?

 

GOOD EYE!!!


Both Melling and Moroso make oil pump drive shafts with the metal collar pinned to it.

 

I talked to some More people about it and they explained to me why this is correct thank you so much for your help this was the key clue I was looking for!
Looks like someone re-ringed it but left stock rods pistons crank, so at least I can figure out compression ratio based off that. Thanks again for your help!

 

They are stock 5.565" length 400 SBC connecting rods. You can tell by how the rod is shaped/broached around the bolt head and beam area. The bolt heads are recessed way down towards the parting line (for cam clearance) compared to a large journal 5.7" 305/307/327/350 SBC connecting rod.

The factory pistons will be dished.... you can put a Vortec top end on it with no worries about compression and it will run good.

There are lots of options to build a really great engine out of that block and crank. What you do would depend on how much you want to spend on this project.
Will