Bummed out 400.....

[dmsdak]

Guys I bought a still running drivetrain out of a 74 large chrysler car. Its a 400 B series big block. Also got the 727 which shifted good as well. Brought it all home and blowed it apart. Ok this engine was in an elderly womans car who was the original owner, it still had the steel shim chrysler pentastar headgaskets, but I ran into a bit of a mystery. One head is a 3769902 (440-400 1974), the other head is different its a 3751213 (440-400 1973 motorhome). What I want to know is are these heads similar enough that it wont make a difference on a minor refresh of the engine?? Why would this have happend? Is it a factory using up left over parts, or a service part thats been installed later in its life due to a blown headgasket etc..

Thanks,
Seth

 

[midnightrider1818]

huh. i dunno. this is a good question though. i am also interested on how this may have happened. i suppose that its had a different head put on it sometime in later life though. the numbers on the heads should match i believe

 

[19mopar65]

yeah probably ran into a blown head gasket at one time and was probably replaced at a dealer.....threw on a head that was laying around. I would probably take them off and at least mic the valves to make sure they are the same size....IMO

 

[63RedFury]

You will be good both heads have the same size valves.I bet one was replaced when the car was fairly new.

 

[Meep-Meep]

Yeah, that is strange and probably doesn't make a bit of difference if the heads have similar features. Here are some things to check: Remove the valves from one cylinder on each head. Inspect the intake port floor and see if they are both flat (not contoured like 906's or 915). I know the 902 head is flat but have no idea about the other one. Also look at water passages to see if they are the same. Maybe someone has more info but if everything matches up then I see no reason why you can't use them.

 

[69 Runner]

I know some of you will think "'scuse me?"......but do the heads have the same spark plugs? All of them 13/16?

 

[Elvad]

I wouldn't run two different head parts numbers on the same engine. They may have different size chambers and probably cause it to blow up.....sound familiar? Granny probably never got on it so with her driving it was no problem. Find a match for your non-motorhome head and go from there.

 

[69 Runner]

Wouldn't cause it to blow up. Chances are, those two heads are so similar that it will take some real investigation to find the differences. For instance, a 346 and a 452 are the same head, except the 452 has induction hardened exhaust seats. And figuring you would have to have real hard seats installed during a valve job, your motor wouldn't know the difference between the 346 and 452.

HOWEVER, if that 213 head has the small plugs and "steam pockets" and the 902 doesn't, then I'd probably match one or the other

 

[63RedFury]

They both are open chambered heads same size valves.

 

[Meep-Meep]

I know some of you will think "'scuse me?"......but do the heads have the same spark plugs? All of them 13/16?

Good point. I forgot about the plugs. I know the 413 industrial heads use long reach plugs, but those heads look completely different than the pass car stuff and you would have had to have waaaaaaay to much vodka if you couldn't tell the difference between those :rolling:

 

[69 Runner]

I was thinking about the motorhome heads with the steam pockets. They don't use a 13/16" plug.

 

[Mebsuta]

I know this is an older post, but believe or not, I have those very two casting nos. on my 68 RR (383 hp).

I had the original 906s. I thought they developed a combustion leak, so I went to the junkyard and pulled a set of heads off a truck. I don't remember if it was a 400 or a 440; probably a 400. I noticed 902 and 213 when I got home. They looked identical, and based on what I read, I had them rebuilt and ran them. I thought they ran better than the 906s at low speed, and wide open I couldn't tell the difference.

It's been about 15 years, and I have no plans to take them off.