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2V not 4V...


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So I feel like a dope. Took the car for a drive today, felt great went great. When I got back I was checking the temperatures in the engine bay and found the stamp on the edelbrock intake. I hadn't been able to see it before. At first I thought it said "ZV." Nope. It says 2V! What does this mean? I think it means I have the wrong engine for this car. That sucks. What would it take to turn this back into a 4v engine?

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What does it say on front of you're motors heads? On the front corners of the heads should be stamped a 2 or 4...2 meaning 2v ...4 meaning 4v....Could be wrong intake on 4v heads...Could be 2v intake on 2v heads on original 4v block..All counts what has been done over the years...Check the front of the heads..And motor block numbers...But block numbers are hard to see.

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What does it say on front of you're motors heads? On the front corners of the heads should be stamped a 2 or 4...2 meaning 2v ...4 meaning 4v....Could be wrong intake on 4v heads...Could be 2v intake on 2v heads on original 4v block..All counts what has been done over the years...Check the front of the heads..And motor block numbers...But block numbers are hard to see.

 

Ok, so the heads both say 2 on them. Where do I look for the block?


I can't find a serial number on the block, but on the driver's side just above the bellhousing lower right of the block there is a number 2. Does this mean 2-bolt main or 2 valves? Where else do I look for a serial on the block?

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Went great because you have a 2v intake on 2v heads. While there are some differences in 2v vs 4v blocks on some of the high performance blocks, the bore and stroke is the same. There were 4 bolt mains on some 4v's but not all. There were some wtih peened rods and stronger bolts but not all. There were some with nodular iron cranks but not all. And of course there were some 4v's that had different cams with mechanical lifters ...but it would be unlikely that you would have a Boss engine that someone would only take out the top end and leave a racing block in the car and put 2v heads on it. The 2v is a very strong engine that produces great power when slightly modified (like your edelbrock 2750 alum intake) and produces that power at a lower rpm. I believe that stock torque ratings were very close between 2v's and 4v's and the 4v hp ratings were advertised at rpm's more than 500rpm higher than where the 2v peaked. I believe a 2v with 2:75 gears would be preferable to a 3:75 4v for any trip on the highway for more than 50 miles, and for a street car with an automatic the 2v with better intake and carb, plus a dual exhaust will perform just as well as the 4v's do in original factory form. The Boss 351 is a different story of course. By 72 the 4v's higher rpm needs made the engine much less attractive than he specs on the 71's. and anything that is a Cleveland is better than anyhing that is a windsor.


Your vin will tell you what the car had originally.

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Went great because you have a 2v intake on 2v heads. While there are some differences in 2v vs 4v blocks on some of the high performance blocks, the bore and stroke is the same. There were 4 bolt mains on some 4v's but not all. There were some wtih peened rods and stronger bolts but not all. There were some with nodular iron cranks but not all. And of course there were some 4v's that had different cams with mechanical lifters ...but it would be unlikely that you would have a Boss engine that someone would only take out the top end and leave a racing block in the car and put 2v heads on it. The 2v is a very strong engine that produces great power when slightly modified (like your edelbrock 2750 alum intake) and produces that power at a lower rpm. I believe that stock torque ratings were very close between 2v's and 4v's and the 4v hp ratings were advertised at rpm's more than 500rpm higher than where the 2v peaked. I believe a 2v with 2:75 gears would be preferable to a 3:75 4v for any trip on the highway for more than 50 miles, and for a street car with an automatic the 2v with better intake and carb, plus a dual exhaust will perform just as well as the 4v's do in original factory form. The Boss 351 is a different story of course. By 72 the 4v's higher rpm needs made the engine much less attractive than he specs on the 71's. and anything that is a Cleveland is better than anyhing that is a windsor.


Your vin will tell you what the car had originally.

 

Thanks man. I have been and still am impressed with how the car performs. That is not what I am worried about. I totally agree that the car has great torque and power. It just sucks because the VIN is for a 351c-4v Mach 1. But this is clearly not the right engine. I was just thinking if it only took heads and an intake to turn it back into a 4v I would put that on the long term goals list. But looking at the block and reading a bit more I am definitely going to stick with what I have.

 

It also makes me feel a little better about really romping on the engine and getting after it. If I mess it up too bad, no big deal. Put a more original engine in and call it happy days. until then I will just enjoy what i have.

 

I guess I can still call it a mach 1 just not an M-code.

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So the owner blew up the original 4v reving it to reach peak HP and replaced it with a 2v! Im pretty sure you can drop on 4v heads and an intake. The exhaust manifolds will have to match also. Thats a good amount of coin for not a lot of return. Better to wait until you do a completely new engine if thats what makes you happy. Doesnt sound like you are chasing concours with this car though. BTW there is a guy named Jon Kaase that is a genius and he competes and wins in Engine Masters using the 400m engine, which is an engine that has never ever been given a compliment. He also sells the awsome CHI 3v heads for our engines that is a hybrid of the 2v and the 4v and will allow you to build your engine to dyno at 700hp if you think you need it. I dont

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So the owner blew up the original 4v reving it to reach peak HP and replaced it with a 2v! Im pretty sure you can drop on 4v heads and an intake. The exhaust manifolds will have to match also. Thats a good amount of coin for not a lot of return. Better to wait until you do a completely new engine if thats what makes you happy. Doesnt sound like you are chasing concours with this car though. BTW there is a guy named Jon Kaase that is a genius and he competes and wins in Engine Masters using the 400m engine, which is an engine that has never ever been given a compliment. He also sells the awsome CHI 3v heads for our engines that is a hybrid of the 2v and the 4v and will allow you to build your engine to dyno at 700hp if you think you need it. I dont

 

I don't either. The car is definitely not concours. So not worried there. and the car will likely sit in the garage a lot. i am active duty Navy and about to deploy again so not a lot for anyone to enjoy there except the outside.

 

Do you think this changes something for my engine running rich issues? Maybe something is mismatched?

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Thanks man. I have been and still am impressed with how the car performs. That is not what I am worried about. I totally agree that the car has great torque and power. It just sucks because the VIN is for a 351c-4v Mach 1. But this is clearly not the right engine. I

 

I guess I can still call it a mach 1 just not an M-code.

 

There are several M Code engines where at some time in life the 4V heads were taken off for what ever reason and replaced with 2V heads and intake. Some say the 2V heads are more driver friendly, I don't know since I haven't driven it with the 4V heads on it. My M Code is one of them. I know it's the original M Code engine since the partial serial number on the engine matches the M Code Vin# on the car. I even went so far as to check the Vin# under a fender to make sure the Vin# on the dash hadn't been swapped out. I have a set of 4V date matching closed chambered heads I plan on putting on it to make it original again, but the darn thing is running so great with the current set up I'm in no hurry to do it. But people who know the engines will say "That can't be an M Code, those are 2V heads" then I have to explain everything once again. LOL

 

Bottom line, you may have a M Code engine where someone replaced the heads and intake, check your engine serial number.

 

Jim

Jim

 

M code 71 Mach 1, 351 4V Cleveland, Ram Air (not factory), C6 Trans, 3.5 rear

 

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Besides, your VIN says it's an M-code Mach 1 so that's what it is. Mine is an F-code Sportsroof, no matter what decals I put on it or what engine I throw in there.

Steve

 

[button=http://www.7173mustangs.com/thread-1972-mach-1--1800]The Stable[/button]

 

25yvyp3.jpg

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Its probably valid to point out that 2v referred to 2 barrel carb vs 4v and 4 barrel carb from the factory. It did not refer to valves or number of bolts on the main bearing caps on the crank. So when you put a 650 4barrel on a 2v you get a different picture very quickly. People forget the 4v was a more user friendly version of a nascar engine designed to run all day at 7000 rpm. The 2v in 1971 with quench heads was only a well engineered progression of the Cleveland project.


I gotta ask, because i am really curious and hoping you guys will educate me; for you guys with a 4v and a tach ( i think some automatic trans had tachs right) how often do you drive your car above 4000 rpm? If you have a toploader its a lot easier of course. Holding the rpm up when coming to a light is heaven, but when driving on a weekend whether manual or automatic how often are you above 4k....5k? Because advertised peak HP at around 5400rpm and the 2v peak was around 4000rpm!

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I had the opposite problem with my car... 73 "H" code with a set of 71 "M" code heads

2cossj6.png

97 F150: wrecked, 96 Dodge 4x4: blown motor / donated to the base

88 Suburban 4x4 355 cid 8 inch lift: sold, 95 Celica 5 speed : sold

68 F750 391 cid : sold,  96 F350 7.3 diesel dually : sold

86 Chevy 1500 305 cid c1500: sold, 73 Mustang mach 1 466 cid 5 speed : under construction

89 F350 4x4 cummins swap : sold, 64 Dodge d600: gone

00 Excursion: traded, 72 Mustang mach 1 302: scrapped

73 Mustang coupe: scrapped, 73 ranchero gt

06 Honda crf 450x : sold, 04 Honda vtx 1800

88 Bronco xlt lariat: sold, 76 Charger: traded

95 F350 4x4: sold , 91 Crown Victoria 302: sold

02 Dakota: traded, 96 f250 powerstroke: parts truck

87 f700, 98 e350 powerstroke: sold

03 land rover: traded, 95 f350 dually: part out

95 f350 dually: traded, 94 f150 4x4: traded

97 f250: sold, 76 Maverick 302: sold

91 240sx rb25: sold, 86 firebird: sold

86 Trans Am: sold, 88 westernstar: sold

89 dodge d350: sold, 2000 Dakota 4x4: sold  

84 f350 3+3: sold, 90 bronco: partout

67 catalina, 64 chevy c60

64 jeep j200, 74 corvette stingray

79 Lincoln mark V, 2013 f350: goldilocks

 

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My 71M 4speed car sees 5k+ rpms almost every time I drive it. :D

In reality I probably shouldn't drive it that hard though. Lol

 

Well, my 71M toploader with Don's 3.50 and quench Cleveland with

a cam is about to see 5000 on a regular basis these days.

 

mike

spacer.png

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I had the opposite problem with my car... 73 "H" code with a set of 71 "M" code heads

 

I don't see a problem... I see a solution. :P

1973 Mach 1 Q code 351 4V, 9A paint, standard interior, 3.50 rear, C6 trans.

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For the street, the 2V would run better than the same engine with a 4V. The smaller ports keep air velocity higher creating more torque over a broad range. Nothing wrong with 2V IMO.

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Just cause it has 2v heads..Does not mean the original block is not still in your car...Some people did not like 4v heads..And put on 2v's on...Or one head mite of cracked or lost a valve and all they found was 2v heads ready and cheap.....never presume what has been done too a 40+ year old car...You never know what some person planned for it before you got it...When it comes to clevelands..It is hard to go by just the head stamps....The block stamp is hard to see thou...Its waaaaay in the back under the headers i think...Can be seen with a mirror thou..I seen a few sites that point it out...I got to head to a wedding today..And got to play in a local bar all night...So i cant look it up for ya...But ill try when i get home later.

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unfortunately I can say for sure that it does not have an original block with the wrong heads. The engine was a rebuild at a shop from a cleveland core. I did find a #2 on the block just above the bellhousing connection on the driver's side. Not sure if this is related to number of valves or not but it seems to point to the block and heads being matched up when it was built. Like I said, I'm not too worried about it either.

 

I was out yesterday adjusting the float levels (a local mechanic told me that was a very common problem that could cause a rich condition). They were definitely not set correctly. I put them back to where the manual said to and...fuel everywhere. I do not have a fuel pressure regulator and I do have a mechanical fuel pump. I re-adjusted the floats today a little bit lower and the fuel is staying in the bowl so thats good.

 

I know the carb dumped A LOT of fuel in the engine before I could get it shut off and pulled back off. Then when I got it all put back together today I am getting grey smoke out the exhaust. I think it might just be that excess fuel burning off but wanted to ask you guys what you thought.

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I had the opposite problem with my car... 73 "H" code with a set of 71 "M" code heads

 

I don't see a problem... I see a solution. :P

 

my "solution" was to go with a 466 :p because my old block spun a main bearing

2cossj6.png

97 F150: wrecked, 96 Dodge 4x4: blown motor / donated to the base

88 Suburban 4x4 355 cid 8 inch lift: sold, 95 Celica 5 speed : sold

68 F750 391 cid : sold,  96 F350 7.3 diesel dually : sold

86 Chevy 1500 305 cid c1500: sold, 73 Mustang mach 1 466 cid 5 speed : under construction

89 F350 4x4 cummins swap : sold, 64 Dodge d600: gone

00 Excursion: traded, 72 Mustang mach 1 302: scrapped

73 Mustang coupe: scrapped, 73 ranchero gt

06 Honda crf 450x : sold, 04 Honda vtx 1800

88 Bronco xlt lariat: sold, 76 Charger: traded

95 F350 4x4: sold , 91 Crown Victoria 302: sold

02 Dakota: traded, 96 f250 powerstroke: parts truck

87 f700, 98 e350 powerstroke: sold

03 land rover: traded, 95 f350 dually: part out

95 f350 dually: traded, 94 f150 4x4: traded

97 f250: sold, 76 Maverick 302: sold

91 240sx rb25: sold, 86 firebird: sold

86 Trans Am: sold, 88 westernstar: sold

89 dodge d350: sold, 2000 Dakota 4x4: sold  

84 f350 3+3: sold, 90 bronco: partout

67 catalina, 64 chevy c60

64 jeep j200, 74 corvette stingray

79 Lincoln mark V, 2013 f350: goldilocks

 

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What carb do you have?

 

I have an edelbrock 600cfm 1406 electric choke. Got the floats set where they will close when the bowls are full. So that is good. Now just worried about the smoke. Going to change the oil monday when the VR1 oil comes in. Local Napa didn't have much in the way of options for oil.

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I have used VR1 in my car since i had bought it. Best i have found.

 

Cool, I was reading some stuff that had mixed reviews about it. But I figured try it myself and see if I like it.

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