Attempting Intake Manifold removal/install 1971 400

[HottRubber351m]

Bought a 1954 Merc M10. I bought it as a late life perk. Guess I expected a turn key daily driver. Got fooled by the seller, but that's my bad. As I chase one thing after the other, my current issue is oil sitting in the dizzy recess and "sprayed" about the engine bay. Took out the distributor, checked for buggered O ring. Looked brand new. Replaced it anyway. Got it running again and test drove. Still oil leak. Pretty sure I saw a small stream coming from the front China Wall of the intake manifold. Makes kinda sense cause there's a bead of bubbled red RTV along this area. I assume this was a previous issue that was poorly addressed. I was told and who knows, this was a rebuilt 1983 351W. Casting marks on the block indicate a 1971 400. I realize that a rebuild could have several different vintage parts. The Casting mark on the Intake has the "kiss of death" MCC marking. But if its a rebuild I'm hoping my worries are unwarranted.

Anyway I'm going to remove the In Man. I'm nervous as hell. I've never done anything like this before. Firstly, should I do this considering the year? I think so. What are the alternatives? Not really looking for an answer to that .

I assume I have to remove the dizzy, the water neck and upper rad hose, carburetor and any other wires and hoses that get in the way? I'll take the hood off too for easier access. The In Man looks heavy. I have an overhead winch. I could use that. Are there lifting points on the manifold?. So I carefully take this thing off, cause I've read the china walls are, well like china. Scrape all the old gasket and RTV off. I've read conflicting info about replacing the gasket as opposed to just using RTV? Also read about using front and back rubber "corner brackets" or not? What's the consensus on a really good sealant product?. So in my mind I seal up the bottom of the manifold, let it set up and then lower it onto the block. What's to stop all the goop from shifting out of place while maneuvering the heavy manifold into position? Then re-bolt and torque to spec following the sequence.

Oh yah, just to back up...what am I looking for when I remove the intake? Will I be able to see cracks, imperfections in the decking?

Sorry for barfing this all out. Feels good to get it all written down. Any and all help will be greatly appreciated.

[Fraser]

M block intake manifolds commonly leak oil in that area, get it super clean and use silicon under the tin gasket. You can now get a fiber gasket instead of the tin one, that's what I'll use next time.
The casting marks do not change by year, only way to know is by the stroke and date stamp. Look for the casting mark at the top rear of the block, beside the oil sender, the one on the manifold doesn't matter My '77 had the wrong block, however it stood up fine, so don't be concerned if it is a Michigan block, if it hasn't cracked yet it probably wont. When you have the manifold off, look for clean spots at the very ends of the lifter gallery, a crack will not be easily visible, but the escaping steam will steam clean the area around the crack.
The early blocks were all Cleveland, I think Michigan started in '76, and the problem was corrected in march of '77, so not a lot of bad ones were made.
Most of this is just from memory, but somewhere there is a website with everything you ever did or did not want to know about M block engines, it may bore you to tears.

I wont say you have to change the manifold and carb to a 4V, but they sure wake up a 400.

[HottRubber351m]

Thanks you. Know how I can lift it off with overhead? Too old to muscle it out

[Fraser]

You will have to pop it free with a pry bar first, then it's really not that heavy, just awkward to reach. Just a ratchet strap around the carb base, or onto the studs should work. You can buy a carb plate lifter which will lift the whole engine, but that's overkill.

The only time I was ever able to really get a good seal on that engine, I threw away those rubber seals and just used silicon, but that was 30 years ago, hopefully the new seals are better now, And I have no idea why. but there is more than one type of tin gasket, the last one I used did not sit into the opening correctly, so I had to try another, both were Felpro, but different numbers. This is a job I need to do on my '77, but it will have to wait for now, too many other irons in the fire.

[HottRubber351m]

Good to know. Thank sir

[HottRubber351m]

Been avoiding this intake manifold removal/reinstall, but here we go. According to my block casting numbers and Engine Labs.com I have a 1971 400 (Cleveland). Some controversy over the M and C designation in my mind. Firstly, is there a difference in parts or removal/installation procedures between the two? Need some info on how to remove the intake manifold. How many bolts? I see some bolt heads that don't appear to be functioning as holding down the manifold. I have removed the dist cap and plug wires (all neatly identified for reconnecting) and coil. Looks like the dist shaft assembly needs to come out? Also thinking the water neck? If you think the carb needs to come out, it looks a bit tricky. The engine sits way back in the bay on my 54 Merc M10. In fact it's hard to see/get at things back there... Ok, I crank the (correct) bolts off. I assume the manifold won't get up and walk over to my bench. So do I pry on this? What can I wreck? After I clean the old gaskets and goop off both surfaces what do you recommend as far a replacement gaskets? And should I use new gaskets WITH sealant? Does the sealant go on the block AND manifold surfaces? Do I slightly rough up these surfaces for better adhesion? What's recommended for sealant?
I've looked over the net (obviously poorly) for the answers, but haven't really found what I'm looking for.
I'd really appreciate some advice folks! Thanks in advance

[HottRubber351m]

Man I'm getting old! I guess I had outlined my problems earlier, inwhich Fraser had kindly replied. However, I guess I did outline some more details. So I'm still looking for more info. Sorry Fraser!

[Fraser]

1971 was the first year for the 400, and only year for the highish compression. It was just a 400, the C or M was not needed, they were used after the 351M was introduced in 75 (I think). Just ignore any reference to C or M, it is a 400, and Ford only made one, whereas they had 3 351s and used the initial to differentiate.
It is a while since I have really done much with one, I recall leaving the distributor in once, but that will probably not work with your close firewall, and really didn't help much anyway, the carb can be left on the manifold. You will need a torque chart to re-install, so use that to see what bolts to remove, I think 12 bolts, the four middle ones are smaller and angled straight up. This is all just from memory, if you can find a shop manual from just about any Ford of that era, it will have a more detailed procedure.

[HottRubber351m]

Thanks again Fraser, appreciated

[HottRubber351m]

Ok got the manifold out. Some planning and fabrication made it fairly simple. Made a lift plate to bolt to the carb studs and used over head winch. More for installation than anything. Anyway here's some pics of what I'm seeing. Front small holes (on each side) in the gallery are almost totally plugged. Almost looks like cork material. In fact other than the valley pan, I really don't see any gaskets. I assume the rubber ones are underneath the V Pan? No sign of RTV either?? Do you see anything wonky ??

[HottRubber351m]

More pics

[Fraser]

The oil side is under the tin gasket, so that's where the rubber seals are, they are designed so you won't get them in wrong. Ford never used silicon, so it's not uncommon to be absent, the new gasket will have instructions as to where to use sealer.
The heads are designed to fit either side, so they have water passages front and rear, but the manifold has small or no passages, a bit of a mismatch as I recall, I think that is where your buildup is. Actually, the whole block has that buildup, this is just the part you can see. Clean everything well, and look for clean spots in the lifter gallery when you get the tin pan off.

[HottRubber351m]

Just started cleaning the underside of the manifold. Does this pic indicate the "steam cleaning" ? Upper left in pic. Let you know the rest of the story when I get to the valley pan...

[HottRubber351m]

Got to cleaning up the surfaces. Only one other small "steam " spot on the manifold underside midway above a port on the left side. Didn't notice any spots on the heads in the lifter gallery. Overall looks good, to me anyway. Shopped around in town here for bolts. Nothing.

[Fraser]

I saw a picture in a magazine once, back in the 80s, of the 351 flaw, as I recall it was about here, around the front lifters. either side.I took this picture of a junk core today while out at my farm, I have clearly neglected it.

SUNP0006.JPG

There is a 351 site on line somewhere, which will have a lot better information than my fuzzy memory, but I can't find it anymore.

You can re-use the old bolts, chase the holes with a tap and lightly oil the threads when torquing them. Personally, I would trust the OE bolts more than any Chinese replacements.