I've picked up a used 400 to replace my tired 351M.

I verified it to be a 400 not a 400 rebuilt as a 351M. The block casting number (upside down D7TEA2B) proves it came from a truck. The difficult-to-find crank id, 5MAB, required a toothbrush, light, and a posting here stating where to look. I was glad to see this number means it's definitely a 400 crank (per BubbaF250's great website) .

I'm a little confused by the date stamp at passenger (Right?) front next to timing cover... whether I'm okay with the cracking problem or not. Mine is 77c21P. March of '77 and I'm good, or is it on or before March that's suspect? What's the P or D maybe?

I'm putting alot in it; a new alternator, starter, distributor cap, roter, plug and wires, temp sensor, oil sensor, oil pump (old one didn't easily turn, was gummy too) and fuel pump, thermostat and water neck, and probably a water pump.

I don't want to pull heads at this time so I have something to go by for the rebuild of my 351M engine, which with what remains to do on the truck itself was getting too much for a first timer . Just figuring vacuum and emissions control was stressing me, but I'm starting to feel more comfortable. I did replace the valve covers gasket and things were clean topside as well.

 

The date stamped on the front is the assembly date not the casting date. The casting date is cast in, not stamped. It should be very near the casting code and this is the one you need to be aware of assuming it was cast at the Michigan plant. Look for the plant code which is cast into the top of the block near the oil pressure sending unit. It'll either be a CF (Cleveland Foundry) or MCC (Michigan Casting Center). There were some older 400 blocks cast in the DIF (Dearborn Iron Foundry) but I don't think any of the D7 blocks were. If it's a Cleveland (CF) casting then you don't need to worry about the casting date.

 

I forgot the fact of assembly date. I looked around the upside down D7TE-A2B but could not find the cast date. I checked the oil sending unit and it was cast at the Michigan foundry. Behind the sending unit, trans side, is a cast number appears to be 8h19.

So, any other suggestions, I'd really like to know this is not one of the suspect blocks.

 

OK...that's the casting date. I forgot on the Michigan blocks that's where they put the casting date which in your case is Aug 19 1978 so you should be fine. The assembly date stamp is still a little confusing since there's 1 too many 7s in it and it couldn't have been assembled prior to it being cast.

 

I had a difficult time reading the date at the oil sending unit... it looks closer to an 8 than a six, but all the rest of the information is that it's a '77 400. The crank no. is no help because it was used 1977 or later.

Following this, the number at the oil sending unit may be a blurred 6? I cleaned it pretty well with purple degreaser which is slightly caustic I think, so I am going out to look at it again to see if I can read it better after sitting awhile. The assembly date definitely is readable, but I'll verify that too. The P or D at the end is something I've not seen posted anywhere or in my reference books either.

I'll be back soon, I appreciate your help. I'll check the valve cover label too.

 

The date at the oil sending unit is 6H19 and MCC. Thus cast at the Michigan Casting Center August 19, 1976? The assembly date at front is definitely 77c21 with an ending P.

Valve cover label states it conforms with 1977 EPA and there is a number D7AE-9C485-FB at the bottom of the label.

What's this mean in terms of the defective blocks?

Thanks, I appreciate your help. I have another block I could have inspected if I have to.

 

I've been told the letter at the end of the assembly date stamp is the inspector's initial.

Aug 19, 1976. That's what I was afraid of. Unfortunately that block falls into the pre-March 1977 date which means it's definitely a suspect block.

 

Well, that's not good news... I fell into this despite trying to keep informed. I appreciate your help though I am disappointed. Given the circumstances, what advice would you give? I'll review posts but how and where will I find cracking?

This is an otherwise assembled engine except for installing the new oil pump, fuel pump, alternator, and starter. I've already put on valve covers, new distributor cap, plug wires, roter and plugs, and attached the replacement transmission.

The old motor is 8_ 28 the missing letter is illegible... used a pencil over masking tape and then pencil directly to pull it out, best guess is i or l depending on characters. Still 8 is good since it's after the suspect cast dates.

 

The cracking is in the lifter gallery inside the valley. I used to think that if an engine made it this far in it's life without cracking that it was probably OK but in recent years I've spoken with 2 different people who have rebuilt these suspect blocks and had them crack after the rebuild.

 

I was wondering, would it be possible to reveal the lifter vally cracking, if it does exist, by hydro/pressure testing the engine? I'm thinking something like running water at say 30 psi into the block through the water neck or elsewhere?

I realize it wouldn't replicate a running test at full temp, but could this reveal a gross leak should the previous owner have experienced a severe failure? The oil pan is still off though I'd have to first put the core plugs back in.

Otherwise, I'm going to install the engine and see what it does.

Thanks for the input. Any suggestions appreciated.

 

If you are this far, use the motor. If it cracks you are only slightly worse off than you are now.

 

I have a picture showing where the cracking occurs above the lifter bores, but don't know if I'm allowed to post it, and if I am allowed to post it, I don't know if I could figure out how to do it.

 

Yes you are allowed to post it. You can either use the "Insert Image" icon on the top of the Reply to Thread page or you can load it in your gallery and post a link to it. In order to insert an image it needs to be publicly accessible i.e. on a web page somewhere. You can't post an image if you use the Quick Reply without knowing some HTML code.

Here's an example of an image posted in a directory on another account:



The image is actually located at http://www.pacifier.com/~bbeyer

 

Originally bought a '79 with a 351M that needed rebuilding, something I always wanted to do. To do what's right by those that know more than I, I needed a 400 crank and pistons. Problem was time and money in a tired truck, and more so really, self-doubt about taking the project on knowing as little as I did. I've learned alot though here on the forum, and have rebuilt the carb and eventually figured out the rudiments of the vacuum and environmental control system, all greek before this forum.

Backup plan was get the truck going for now using a replacement 400 engine (from e-bay) and then build myself a garage (I've saved the money to do it) where I could rebuild an engine in more controlled leisure.

Every bit of it's a learning experience that lessons my doubt. I can use all the peripheral parts I've gotten, a starter, alternator, fuel pump, etc and I have an edelbrock carb, bolt set here from Motorhaven, but not yet the intake.

Your probably right about just putting it in and seeing what it will do cause that's one more thing done.

Now comes Bill--- it really burns me green with envy having him post a picture like that ! Dadblamedit.

 

Hi
I have a question. I live in Germany and own a motor with transmission exect the starter is missing ( D7TE/A2B Big Block ). I´m thinking about selling it but don´t know nothing about it at all. Don´t know what it´s worth. It´s like new.
Could you or anyone here help me out?
Regards
Ben