I have a '78 Mercury with a 400M (yeah, I know it's a car & not a truck, but I need help with the engine), and I'm looking to wake it up a bit. I've been told this engine's a boat anchor, but it's 400 cubic inches! That much displacement has to be good for something! Anyway, I was hoping I could get some answers on some very basic questions.
First, what's the difference in 2V and 4V heads? (Does the V stand for valve? I haven't heard of 4-valve per cylinder pushrod heads.)
Also, doe anyone make intake manifolds that will work with the 4V heads on a 400? If not, how hard will it be to custom-make an intake manifold?
I have a little plastic & styrofoam Thunderbird that has gotten me spoiled to overdrive and fuel injection. An E4OD transmission should satisfy my desire for an overdrive, but does anyone make electronic fuel injection for a 400M?
Final question involves the ignition system. Ford distributors have always been pretty good, so am I going to see any real advantage with some fancy, modern distributor, or will a well-tuned stock system provide plenty of spark.

I've been told the best thing I can do with a 400M is to yank it and drop in a 460, then plant flowers in the 400. I don't beleive that. Besides, I want to see the look on my dad's face when my Mercury with the 400 blows his almost stock 460-powered 77 Lincoln away!

 

[updated:LAST EDITED ON 06-Dec-01 AT 11:06 PM (EST)]The V represents Venturi's or throats in the carburetor. So a 2bbl carb is a 2V and 4 bbl is a 4V. So what your talking about is 2bbl heads and 4bbl heads. This applied to the 351 Cleveland engine's. The 2bbl C heads had the same size valves as the 351M & 400 heads just the cc was a bit smaller. I have seen reference to 4bbl's being on 400's but have never seen one anywhere, in the States anyway.

The Duraspark II is a pretty good unit stock in my opinion, but thats just it, my opinion.

 

You can pep that 400 up real easily and fairly cheap if you don't want to do a complete rebuild. Put on an Edelbrock intake, 650cfm carb, cam, timing chain, and headers. Used intake from swap meet or Ebay $85, new cam and lifters $150, 4 barrel carb from a buddy $100, and a cheap set of headers $95. Not everyone here will agree with the headers, but try to make the exhaust flow a little better somehow. If you are a beginner, you are looking at a full weekend of work here. One more day for all of the gaskets to dry, and back on the road the third day. This will kick the snot out of the stock 460 Lincoln at least up to 100mph. After 100mph, the 460 may catch up.

 

>I have a '78 Mercury with a 400M (yeah, I know it's a car &
>not a truck, but I need help with the engine), and I'm
>looking to wake it up a bit. I've been told this engine's a
>boat anchor, but it's 400 cubic inches! That much
>displacement has to be good for something! Anyway, I was
>hoping I could get some answers on some very basic
>questions.

Well the bad news is you don't own a Ford truck...the good news is at least you came to a board where the 351M/400 (no M) series is appreciated.

>First, what's the difference in 2V and 4V heads? (Does the
>V stand for valve? I haven't heard of 4-valve per cylinder
>pushrod heads.)

You're talking about Cleveland heads. The V stands for venturi. The M heads, which are basically identical to the Cleveland 2V heads, didn't come in 4V configuration. Cleveland 4V heads came in 2 styles, open and closed chamber. Both styles have larger intake ports and larger valves. Regardless, either set of heads will fit the M series.

>Also, doe anyone make intake manifolds that will work with
>the 4V heads on a 400? If not, how hard will it be to
>custom-make an intake manifold?

Any Cleveland manifold will fit the M series if you use the adapter spacers from Weiand.

>I have a little plastic & styrofoam Thunderbird that has
>gotten me spoiled to overdrive and fuel injection. An E4OD
>transmission should satisfy my desire for an overdrive, but
>does anyone make electronic fuel injection for a 400M?
>Final question involves the ignition system. Ford
>distributors have always been pretty good, so am I going to
>see any real advantage with some fancy, modern distributor,
>or will a well-tuned stock system provide plenty of spark.
>
>I've been told the best thing I can do with a 400M is to
>yank it and drop in a 460, then plant flowers in the 400. I
>don't beleive that. Besides, I want to see the look on my
>dad's face when my Mercury with the 400 blows his almost
>stock 460-powered 77 Lincoln away!

Hang around this forum and use the serach feature to look up some older posts on improving the performance of the M series.

 

Thanks for all the advice guys. This is really the first board I've been to that hasn't told me to drop in a 460 and be done with it. The engine's got 122,000 miles on it, and, from what I've gathered here, the best way to get more power is 4V heads, Weiand spacers, new intake and 4bbl carb, cams, and playing around with the timing. There's really no point in doing all that to a bottom end with 122,000 miles, so I'll probably end up doing a complete rebuild (definately not a weekend job). Still, I know the potential's there, and I'm getting a good idea of what I need to do. 13 pages of topics is a lot, but I spent a lot of time last night and this morning skimming through them, looking for tidbits of useful information.
Again, thanks for the advice.

 

>...from what I've gathered here, the best way to get more power
>is 4V heads, Weiand spacers, new intake and 4bbl carb, cams,
>and playing around with the timing. There's really no point
>in doing all that to a bottom end with 122,000 miles, so
>I'll probably end up doing a complete rebuild...

Before switching to 4v heads, be aware that the 2v heads are better at low end torque. I suggest that instead of swapping to 4v heads, you have your current 2v heads fitted with the larger 4v valves. This, combined with some mild port massaging by someone that knows what they are doing will offer more low-end grunt than either the stock 2v heads or the 4v heads. You will be able to use an off-the-shelf intake such as the Performer - and no spacers.

If you are rebuilding and end up replacing the pistons, raise the compression if possible (to 9.5:1 or so), and keep the boring as low as possible since the Cleveland block can overheat if overbored (some have had problems even at .030). Also be sure to use a low-end torque cam, and a straight-up timing chain set.

This engine is known for low-end torque rather than high RPM power, so it would be advantagous to select parts that further improve low-end torque. A 400 that I built sheared off the input shaft on the C6 transmission - so they will really make some torque!

 

Hi, I own a 1977 t-bird, with the 400, (same body as your mercury). My current engine has a edelbrock performer manifold, 750 Holley (thought the 600 CFM I had before worked alot better) and a 268 Comp Cam. With the 3:1 gear in back, it will eat a stock 460 for lunch. The 4-V heads will not build enough intake velocity in a heavy car such as your Mercury. (resulting in your car being a slug off the line) Also, raising the compression above much higher than 9:1 with the open chamber 2 or 4 bbl heads will cause some severe detonation problems on pump gas. If you don't want to sink much money into the motor, go with something like the combo I described above. However, if you are willing to spend the money, Australian Cleveland heads (4-V closed combustion chamber (58 CC) and 2-V ports) with dished pistons, for about 10.5:1 compression is a good start on a killer engine. (this is what I am in the process of building right now. [just dropped the block and crank off at the machine shop]. I haven't been able to find anyone that makes headers for this style of car. If anybody knows, let me know.

 

Maybe I'm looking at this the wrong way. I knew the 400 was great for making low end torque, and since I don't plan to do much stump pulling, I figured I'd go with the 4V heads and try to get some good mid range horsepower. I want a car that can effortlessly cruise at 80-85 mph all day long, (With the requsite short runs and triple digit speeds) rather than a drag car that can light 'em up off the line. (But I'd still like to smoke my Dad's Lincoln! ). Would the 2V heads be the best bet for this?

(See, this is why I ask people who know before I go out and buy the wrong parts. Thanks guys!)

 

Go with the 2-V heads. You will be much happier with their performance at low, midrange and top end. (not to mention the money you will save.) My T-bird won't win any 1/4 mile races, but it will consistently do 140+.

 

What hasn't been mentioned, that I've seen anyway, is the issue of open chamber vs closed chamber heads. AFAIK all US 2v Clevland heads are open chamber (~78cc), whereas 4v heads are available in both open and closed versions. With 4v heads the intake volume is so large flow velocity suffers at low(er) RPMs giving (relatively) low torque output. If I were head shopping again I would watch Ebay for a set of Austrailian 2v heads which have the smaller intake ports of the US 2v heads, and the closed chamber design of the 4v heads ( maybe 65cc). This greatly improves the quench characteristics of the chamber, provided you reduce the deck height which is ~.120" on a 400 and gives a useful compression boost even with the stock dished pistons. At the same time get a set of single groove valves/retainers and a decent set of valve springs and you will have a set up which rivales the aluminum heads, available for other Ford engines, at a fraction of the cost.

 

I had my heads machined on my 400 .015", and used a set of TRW 8.4:1 '71-'72 pistons, with a .030" overbore. Compression ratio is now at about 9.1:1.

Good streetable CR. Stock valves are pretty big to begin with (2.04 intake, 1.96 exhaust), so I had a 3-angle valve-job done to improve the flow & sealing characteristics a bit.

Went with a set of Crane stamped steel 1.73:1 ratio rockers, with the roller fulcrum conversion, running an Edelbrock Performer cam, timing set, intake, & 600 cfm carb.

High volume oil-pump with constricted mains at #'s 2,3,&4 to improve cam lubrication, aluminum high-flow water pump, Accel distributor, Jacobs Ignition, all new ARP fasteners.

This thing is a brute! Ran it for a while in a "beater" '77 F-150 short-box to dial it in. TORQUE!!!! Once it hooked, it would fly. Wrung out by 5200 RPM (w/a C6 & a 3.25:1 rear gear). FAST.

Such a combo in a big passenger car would be a scream. Better traction, similar weight.

 

>Good streetable CR. Stock valves are pretty big to begin
>with (2.04 intake, 1.96 exhaust), so I had a 3-angle
>valve-job done to improve the flow & sealing characteristics
>a bit.

Exh valves are 1.66" not 1.96"...

Sounds like a pretty healthy motor.

 

[updated:LAST EDITED ON 21-Dec-01 AT 10:00 PM (EST)]>>Good streetable CR. Stock valves are pretty big to begin
>>with (2.04 intake, 1.96 exhaust), so I had a 3-angle
>>valve-job done to improve the flow & sealing characteristics
>>a bit.
>
>Exh valves are 1.66" not 1.96"...
>
>Sounds like a pretty healthy motor.

Doh! You are correct, sir!


My typing skills are not what I'd like them to be!!!

 

>
>Such a combo in a big passenger car would be a scream.
>Better traction, similar weight.


well....I'm doin' it. I'm putting a mill very similar to yours in a big passenger car. I hope it does turn out to be a scream--that was the point of spending all this money, anyway.

I've been following this board and the Project Bronco M-block board for a few months now (because of the fact that truck guys are MUCH more knowledgeable and enthusiastic about the M motor than your average Galaxie or Torino fan), and my 1972 LTD's new D7TE 408 is about to be assembled.

...Same cam/timing/valvetrain combo, same size Holley carb, but I'm using a Weiand 8010 intake, aluminum roller rockers and the good old DuraSpark (for now). I also went with the Badger flat-tops and had a little more metal taken off the heads--we were shooting for just under 9.5 to 1. The rotating assembly was balanced, and we're even going to try and get a set of headers in there. That's the big question mark right now, because nobody seems to make a set specifically for that application. In fact, good luck trying to find ANYTHING for a Galaxie or LTD built after 1968. Anyhow, Hooker and Thorley make a set of headers for the 400 in a Fairlane/Torino/LTDII. While nobody, including the manufacturers' tech departments, seems to know if it will work, I think it's worth a try.

Thanks to all of you for your informative posts. They have helped me a great deal. And for what its worth, I don't even care what the "M" stands for. I just like torque.

72LTDConv

 

Man I would love to find a decent 70's LTD ragtop with a 351M or 400 and really build a monster engine for it. Custom pistons, 32 valve aluminum heads, big ol' nasty roller cam, full roller valve train, the whole works. That would definitely be a great car to cruise as well as scare the bejeezus outta the bowtie brigade.