I've got a 71 Monterey with a 400 and im close to completing the tear down for my top half rebuild. the problem im running into is getting the exhaust manifolds off. a couple of the bolts broke their heads off and a couple rounded themselves off due to 30 some odd years of corrosion and the weirdest thing about the whole situation is that the bolts are 14mm. metric on an american engine, any hoo, would you suggest cutting these stripped bolts off, and where could i find replacements. How should i go about removing the rest of the bolts from the heads? Any advice would be greatly appreciated.
-NeRv

 

Are you replacing the manifolds with headers, or using the same manifolds? Alot of the time, headers will come with new bolts. If you are re-using the old manifolds, you can likely find exhaust manifold bolts at Autozone or Napa.

As far as getting the old ones out, that always scares me. Some people will tell you that you can drill and tap them, and I am sure you could, but I was never any good at that, so when I found a broken bolt in my water pump in my engine, I took it to the machine shop that built the engine and let them handle. It made me feel better letting them do it, because I didn't have experience with that sort of thing.

My 2 cents...

 

I would also take these heads to a shop to get the broken bolts out.
The heads are still good right now but if you make a mistake drilling out the broken bolt, things will get more expensive than just getting it done by a shop.
Just my 2 cents.

 

one trick that i heard a while back is to heat the bolt and take a candle just a regular old candle and melt the candle on it several times the wax will percilate up into the threads and losent the boltl. havent gotten the chance to try it yet but it might be worth a shot


The Northwest chapter will kick the shiznit out of your chapter

 

Yes, as already recommended, just get the manifolds off and break as few bolts as possible, then let the machine shop dig them out.

A tip for next time, though. Get a good bite on the bolt with a box end wrench and give it a tug in the loosening direction, then give it a tug in the tightening direction, then a little harder tug in the loosening direction, then a little harder tug in the tightening direction. Go back and forth with a little harder tug every time. If you ever get the bolt to move even just a little bit in either direction, you will then be able to back it the rest of the way out.

Now, that we're past your question, there are many of us here that will have a question or two for you. As 400's go, you have one of the VERY FEW '71 models. Is it a four barrel and when you get the heads off tell us about the pistons. The later models have deeply dished pistons. The '71 as legend goes has flat tops or much more shallow dished pistons.

If it is a four barrel, does it have quench chamber, huge port heads? If this is a 4V engine, it is absolutely rare as hens teeth and most guys have never seen one. If it is a 4V many of us would appreciate pictures of the pistons and heads.

Have a great day and good luck with the valve job,
Doc

 

As far as I know Ford never made a 4V 400. There is no such thing as a factory 4V manifold for a 400. The '71 400 was a 2V motor with open chamber heads and flattop pistons giving 9.0:1 CR.
There were some 400s with a small block bell housing bolt pattern, but they were also 2V motors.

 

If the heads have snapped off and left the shank sticking out of the head then you're lucky. There's quite a few ways to get them out without going to the machine shop. If you're already planning on taking the heads off then go ahead and do it with the manifolds on. This way you can set the head on the bench a get leverage with the right tools.

Get yourself some Kroil or AeroKroil. You can find it online or if you're lucky some industrial/farm supply retailers sell it. I've tried PB Blaster, Liquid Wrench, etc. and none of them work nearly as well as Kroil. With the head on the bench and the bolt shanks sitting straight up spray a little Kroil on the point where the bolt enters the head and let it sit for a little while. If you want to take out some aggression give it a few good raps with a hammer straight down from the top.

You can use vice grips or if you feel the need to buy some cool tools get a stud extractor set from OTC. They look like spark plug sockets but inside is a set of hardened rollers that clamp down on the shank and tighten up as you turn them. I got a set a few months ago for $35 online.

Patience is your friend here and liberal amounts of Kroil. If you still can't get it to move then you may have to go with the old flame wrench. The trick is to heat the head quickly but not the bolt. If you have access to a MIG setup then welding a nut on the end of the shank is a good alternative as well.

If you've broken the bolt off inside the head then it's a whole new ballgame. I've never had much success getting busted bolts out without using a MIG welder...maybe 1 in 10. Prior to getting a MIG I just ended up taking them to the machine shop usually after breaking off an EZ out.

If you do have a MIG or a friend with one then take a flat washer and weld it to what's left of the bolt. If the bolt is flush or a little below then take a hammer and dish the washer a little in the middle to get as close to the bolt as possible. Weld the washer to the bolt and then weld a nut to the washer. Again, liberal amounts of Kroil and patience will help here.

 

The books way back when indeed listed a 4v 400, but I have never seen one and I've never talked to anybody who has seen one.

Have a great day,
Doc

 

Which books?

 

Ford Performance, published by SA Designs, copyright 1979, edited by Larry Schreib,
Page 91, "a four barrel model was listed for the first year of production, but we have never seen one."

Since I read that many years ago I have watched for, but never seen one.

Have a great day,
Doc