internals on 71 351 m

[old henry ford]

i just purchased a 71 Mach 1 with a 351m 4V with a C6 for $5,000 lastweek and i'm trying to find out if the crank,rods and pistons came forged or cast and what type of pistons { popups } or flat tops ? any info would be greatly appreciated thanks

 

[red351]

Are you sure it's a 351M. Never heard of a M being a true 4V?

 

[old henry ford]

Are you sure it's a 351M. Never heard of a M being a true 4V?

no just going on the vin #

 

[old henry ford]

i thought the 2V motors were 2bl or 2 bolt mains and 4v were 4bl motors with 4 bolt mains, what exactly is the difference between the to ?

 

[tony-muscle]

I think he means an M code which has the 351-4V. The 4V or 2V refers to the heads.

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[secluff]

Nice find! Looks to be in  pretty solid shape and well equipped with the right options. The Mach 1 Deluxe Interior, fold down rear seat, instrumentation group, AC, C6, Ram Air and M code 351 4bl are all desirable item's to have on a Mach 1 like you have acquired.

The pistons are cast flat top with valve reliefs like used in all 351C engines (Except Boss 351)  across the Ford product line. The crank is cast iron but was a pretty durable unit since Bob Glidden had been known to turn his Pro Stock cast crank to 10,000 RPM! Rods used were the same ones used in all non Boss standard 351's across Ford's product line. The Boss rods were shot-peened and magnafluxed and very expensive.

I own two M code 71 Mach 1's and I can promise you they have been ridden hard and put up wet. Very tough engines!

A lot of knowledge and experience on this forum and all willing to share and help in any way you need.Just let us know what you need!

 

[old henry ford]

thank you sir and yes that's what i meant an M engine code and do know what the rotating assembly was forged or cast for that motor and what type of pistons they were, thanks

 

[nailpounder]

very nice find

 

[old henry ford]

very nice find

thank you for the info and the car was restored 25 years ago then the owner died and car was sold where the last 4 years it sat in a field next to the woods and fortunately underneath the car is very solid as well as the rest of the car, the guy went with the 71 Boss theme which used to be called clones and nowadays their called recreations but i called them for what they are { FAKE ] but i want to continue with his theme. while the car sat outside the carb, ramair filter, radiator,condenser and wheels were stolen so i have found an original 71 ramair filter and purchased an Autolite 4300D carb for it and searching for the rest. since the radiator is out of the car i want to pull the motor and paint the engine bay back to black and clean and paint the motor after i install a solid lift cam and period correct aluminum intake and possibly find a correct rev limiter to make as close to the real Boss 351 as possible. just joined this forum 2 nights ago and it has already been worth it on info and parts searches. thanks to everyone who has replied, GREATLY APPRECIATED

 

[Stanglover]

Hi and welcome to "our" Forum.

What a find!! lots of potential and as Steve said, it's got all the right stuff (I wish MY M code had). I may get into that later, but for now and without going too far in details, make a list of everything you'd like to do, when you want to do it and how much it will cost. Clearly you have some good basic knowledge, but do you really want to make it into a Boss clone, recreation or fake, what ever it's called now? It may be worth more as an M code through and through, but if that's what YOU want, go for it, but it won't be cheap. I think others will agree, finding some of those BOSS type parts may be hard especially if you want it looking authentic.

I'm no expert and don't pretend to be. People like Steve have far more knowledge and experience and others will chime in in due course I'm sure. We all manage to add something from our own experiences that will be most helpful to you going forward.

Anyway that's my input for now. What I can offer is some of my engine bay detailing experience. I do NOT go for a concours restoration, waste of money imo, but I do like it to "look" right to the casual observer.

Geoff.

 

[SVO2SCJ]

Hi Welcome ! That looks like a good base to start with and I'm sure you can come up with a good car!!

There isn't anything wrong with an M code car !! in fact, being an Automatic /AC car it would be a great driver as that (and look good with the Boss look) IMO.

Take you time, research the NEEDS of an auto/AC car and you might find "converter ala CobraJet/ NON higher RPM (what you have now) is the right combo for the compressor etc etc. I say research because MANY get a car, want to omit/gut (read make faster) and don't think of effects on drivablity or values. I SAY VALUE - as the starting point for any car IMO is a "marti report" to see what you have in comparison to what was built (or how rare)! Granted if you find a car is a "frankenstein" already it is hard to justify restoring - BUT if you find you have a rare car (say a color combo or options list you money is protected "investing" in it.

Mostly just happy for you - again looks like a great project! So SO much easier to find parts for an M code (than a Boss) AND the time needed will be 5X's less and 10X's less in costs. We have all done that to 1971's years ago !

 

[Hemikiller]

very nice find

thank you for the info and the car was restored 25 years ago then the owner died and car was sold where the last 4 years it sat in a field next to the woods and fortunately underneath the car is very solid as well as the rest of the car, the guy went with the 71 Boss theme which used to be called clones and nowadays their called recreations but i called them for what they are { FAKE ] but i want to continue with his theme. while the car sat outside the carb, ramair filter, radiator,condenser and wheels were stolen so i have found an original 71 ramair filter and purchased an Autolite 4300D carb for it and searching for the rest. since the radiator is out of the car i want to pull the motor and paint the engine bay back to black and clean and paint the motor after i install a solid lift cam and period correct aluminum intake and possibly find a correct rev limiter to make as close to the real Boss 351 as possible. just joined this forum 2 nights ago and it has already been worth it on info and parts searches. thanks to everyone who has replied, GREATLY APPRECIATED

Not sure if it was answered, but the 70-71 M-code engines had cast flat top pistons with a valve relief. They are extremely durable for a cast piston.

Regarding the carb, you need a 4300, as it's a square bore intake in your pics. The 4300D is a unique Ford spreadbore pattern and won't fit anything but an intake designed for it. You could also use a Holley or Edelbrock if you prefer to swing that way.

 

[secluff]

old henry ford, lots of great info so far. You'll find most of these folks were in the same club as I was a member of. The "Been There, Done That" Club. As SVO2SCJ posted once you determine the direction you want to take with this car you can focus on making it what you want. As is, the "M" 351's were a very versatile engine. They could be had with AC, AT, and a host of other creature comforts, but at the same time could hold their own at the "Red Light to Red Light" drag strip on any typical Friday or Saturday night.

The quest to replicate the Boss look under the hood, while not impossible, will be difficult and expensive. As mentioned by Hemikiller, the standard Boss intake used the 4300D speadbore. While a decent carburetor in the 70's, most people hate them now! LOL  There was a over the counter intake that used the "Squarebore" pattern so a Holly or a 4300(A) carb could be used. The production installed Boss intakes (D1ZZ-9424-F) are an easier and a little cheaper find. The D1ZX-9425-DA  squarebore is a rare find and can be Very expensive!!

The engine governor or "Rev Limiter" is another $$ part to track down. Most of these were pitched in the name of performance when these cars were new. My friend's philosophy was that if it didn't help with making horsepower, it was evil and needed to find it's way to the trash can! If I had only a fraction of what my friend's had thrown away I would be very well off now! They do pop up occasionally, but....save your lunch money! Unfortunately the same limiter was also used on the 69-70 Boss 302. And since those cars cars are now in the six figure arena, restorers are paying the big bucks for these type of parts.

Keep us posted and be sure ask any questions you may have as you decide which direction you decide to take your new Family member.

 

[Hemikiller]

Something I forgot to add is that one of the best performance upgrades to a C6 equpped 351C is a higher stall converter. At the least, a 351 Cobra Jet spec type converter is needed, as the stock unit was pretty poorly matched to the engine.

 

[secluff]

old henry ford, Hemikiller hit the nail on the head. Other than a complete rebuild with a high performance valve body, the high stall torque convertor will give you the most bang for the buck without going into the transmission. The 72-74 "Q" 351's had a production installed high stall converter. The original converter had 8 studs and was used until 5/72 when it was replaced by a 4 stud unit that was utilized until the end of the Q engine production. You'll hear different numbers on the stall speed but the Ford service specifications give a 2750-2950 RPM range which is what I was told by the dealer when I bought my first Q code powered car. You'll find that is the sweet spot for a 351 "M". The stock converter in my 71Mach 1was the same one as in my Dad's 74 LTD with the 400 engine. Fine for his car but useless for my late night illegal drag racing. Too little RPM and the car launched like it was pulling a trailer of concrete blocks. Just a little too much and the tires would roast! Once it was equipped with the CJ style converter and flywheel, (Along with a few other "Things" over a period of time) it was launching and running with the Big Block boys. It was actually allowing those large valves and ports to work like they they were supposed to.

The Ford converter was discontinued in early 1982, but aftermarket units are available that will "Loosen" your engine up if that is the direction you decide to pursue.

Now, if you need any other ideals so we can help  spend your money, just let us know!!  

 

[libram]

really impressed with the interior, its in great condition, be careful with that tach and trip odo lens. For that matter every other little piece of that interior, you seem to have a gem there.

 

[DK73]

Welcome from Denmark Regards Lars DK73

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[Boss1Ray]

I agree - nice find! I also think this car would be more valued as a 71 M code than a Boss Clone.

But welcome and enjoy the car!

Ray