351c 680hp

[Boss1Ray]

To clarify-

The 351 Cleveland motor was an optional motor available in the following USA production years/models:

'70-73 Mustang, '70-74 Torino, Ranchero, Cougar and Montego's

Non USA built vehicles including some DeTomaso Panteras and Longchamps also used the 351C "Cobra Jet version. And then there was the Aussie production of the 302C and 351C's - some great related performance motors...

Variations of the USA 351C motor were built for the passenger car and light-duty truck lines and were called the 351M and 400's and while both were derived from the same 335 engine family they are only correctly called the "351M" and "400" engines. BTW "335" is the distance between the centerlines of the camshaft bore and the crankshaft bore.

351C, 351M and 400: 3,35 inches.

Neither of these variants were built as passenger car performance engines. And none of these engines in this 335 engine family were ever installed as a regular production option in any Ford Van - although swaps were VERY common. With much modification the 351M'sand 400's can be made to perform well. With everything else being equal a 351 C or 351 W engine make a much better performance choice. Again Ford built these 351M's and 400's to power heavy family sedans, station wagons some Lincolns and Mercury. and pickups - all requiring decent torque at a lower RPM. The 400 was actually designed off the 351M to pass emission standards that began around 1971 as the old FE 390 would have never been able to meet the more stringent requirements.

Most Ford Marine engines were/are indeed 302, 351W or 460 motors as supplied to various boat manufacturers. Of course over the years inline 6's, Y blocks and even some FE Ford (mated to V-drive speed boats) engines were sold by Ford to be used in marine applications. But no 351 C engines were sold for marine applications. Many think the Ski Nautique boat (manufactured by Correct Craft) came originally with 'marine' 351 Cleveland but they actually were sold with Ford marine-based 351 Windsors.

Good luck with your build. Sounds like you want it to pull hard. Enjoy your car for what it is - a classic Mustang.

Remember many of the newer model performance Mustangs with 600+ reliable, usable HP on tap with air conditioning and crazy tight handling might be able to eat your lunch. A new 6 cyl Mustang has about the same HP as a stock Boss 351 did.

And BTW I have been incorrect before and I am always willing to learn. I like to review information and documentation that may be contrary to what I have posted. If anyone has something please PM me with any reference material/information that supports your position. This is how we all learn and make this site as factual as possible.

Respectfully.

Ray

 

[cudak888]

Question - is this your engine block?

You mention you have both M and Q-code heads. Are the Q-code heads late-'73 with the smaller intake ports or earlier?

Also - at what RPM are you hoping to hit 680HP?

-Kurt

 

[maverick70351c]

The reason I said no stroking is because ive heard it will eat the bearings in the lower end, Is this correct or wrong? ceheler someone calculated that compression rato wrong it would be more like 10.8:1 for 70cc heads and flat top positons

 

[ceheler]

I do apologize that is a build that a friend of mine gave me on a piece of paper i probably copied it down wrong. As far as eating up bearings i have never hear of the issue. Not saying it doesn't exist i just haven't run into it.

 

[c9zx]

The reason I said no stroking is because ive heard it will eat the bearings in the lower end, Is this correct or wrong? ceheler someone calculated that compression rato wrong it would be more like 10.8:1 for 70cc heads and flat top positons

Stroking a 351C does not cause bearing failure. Here is a link to a stroker post. http://www.7173mustangs.com/thread-dyno-sheet-408c-pump-gas?highlight=dyno

Chuck

 

[turtle5353]

There's nothing wrong with building a stroker. And if you want to use the heads you mentioned, its needed to take full advantage of them. To get 680 HP out of a 408 stroked Cleveland with AFD 4v heads is definitely doable. But it will not be street friendly at all, and you will need to run race fuel, not pump gas. I can tell you this from experience. Last year I just built a 408 with AFD 4v heads. My compression was around 11.75, too much for pump gas. We were able to get it down to around 10.25 and I can run high test pump gas. I went with a fairly mild cam to run on the street. Its healthy but not crazy by no means. Its a big mutha thumper hydraulic roller cam. I am running a 950 cfm quick fuel carb, 3000 stall converter and 3.73 gears. The machine shop estimated the HP around 550-600 in current trim. He also said if I wanted to go crazy with it in the future I could easily bump the compression back up to 11.75, run a bigger solid roller cam, a bigger carb and race fuel and easily hit upper 600's for HP. I can honestly say that the 550-600hp now is a handful. you have to be very careful when and where you push the throttle. 45mph I can jump on the throttle and blow the tires off. Here's a link to my build if you want to check it out, has all the components listed that I used. http://www.7173mustangs.com/thread-my-408-build-its-alive

 

[MotoArts]

I can honestly say that the 550-600hp now is a handful. you have to be very careful when and where you push the throttle. 45mph I can jump on the throttle and blow the tires off.

(Dude, I need a ride in that thing! )

 

[turtle5353]

I can honestly say that the 550-600hp now is a handful. you have to be very careful when and where you push the throttle. 45mph I can jump on the throttle and blow the tires off.

(Dude, I need a ride in that thing! )

LOL yeah its fun!

 

[73vertproject]

I can honestly say that the 550-600hp now is a handful. you have to be very careful when and where you push the throttle. 45mph I can jump on the throttle and blow the tires off.

(Dude, I need a ride in that thing! )

+3.73!! dancebanana

 

[Luke]

The reason I said no stroking is because ive heard it will eat the bearings in the lower end, Is this correct or wrong? ceheler someone calculated that compression rato wrong it would be more like 10.8:1 for 70cc heads and flat top positons

Stroking a 351C does not cause bearing failure. Here is a link to a stroker post. http://www.7173mustangs.com/thread-dyno-sheet-408c-pump-gas?highlight=dyno

Chuck

Great flat tq curve Chuck, gets over 450tq early too. Nice build.

 

[DK73]

This is My engine Torque and His[WINKING FACE] Regards DK73

Regards DK73



Regards DK73

[emoji1]

Regards DK73

 

[c9zx]

The reason I said no stroking is because ive heard it will eat the bearings in the lower end, Is this correct or wrong? ceheler someone calculated that compression rato wrong it would be more like 10.8:1 for 70cc heads and flat top positons

Stroking a 351C does not cause bearing failure. Here is a link to a stroker post. http://www.7173mustangs.com/thread-dyno-sheet-408c-pump-gas?highlight=dyno

Chuck

Great flat tq curve Chuck, gets over 450tq early too. Nice build.

Thanks. For the money spent I think it turned out good. It does over power the stock chassis tremendously. As it was a show and go build I didn't want to add sub-frame connectors and Cal-Tracs. If I keep it, they may have to be added. Chuck

 

[barnett468]

The reason I said no stroking is because ive heard it will eat the bearings in the lower end, Is this correct or wrong? ceheler someone calculated that compression rato wrong it would be more like 10.8:1 for 70cc heads and flat top positons

clevelands have inherent oiling problems . . building an old block to big hp and/or rpm without correcting some of these probs is what causes bearing failure.

.

 

[4Vforever]

Stroking a 351C does not cause bearing failure. Here is a link to a stroker post. http://www.7173mustangs.com/thread-dyno-sheet-408c-pump-gas?highlight=dyno

Chuck

Great flat tq curve Chuck, gets over 450tq early too. Nice build.

Thanks. For the money spent I think it turned out good. It does over power the stock chassis tremendously. As it was a show and go build I didn't want to add sub-frame connectors and Cal-Tracs. If I keep it, they may have to be added. Chuck

Great build Chuck, very nice flat torque curve, the thing would pull like a train. One thing I really like about your build is that it's a solid flat tappet cam. The amount of people that go on about rollers and how great they are (which they are) but shut up very quickly when shown great figures made with a flat tappet cam. Those 4V's you used on your build were the intake ports left untouched or filled on the floors. I absolutely love using factory cast iron heads and make big power, especially against the Chevy guys. The guy I worked for years ago, in a full weight XY Falcon (all stock interior with ANDRA spec cage, factory panels) standard rear wheel arches (bloody tight fit getting the slicks in) It ran a 380ci stock cast block and 4V CC heads, C4 trans braked auto, 9 inch diff with 4.56 gears (pretty sure) this thing ran 9.5's in this configuration. It was hilarious at the 02 Winternationals, his car was getting a pretty serious reputation around the country. Had all these southerners coming up checking the car out, we stood back listening to the comments of people looking for a lightened car (fibreglass panels, lexan windows etc) and coming away scratching their heads finding a factory based car. Also I find it interesting about what compression ratios you guys run because you have dramas with detonation. We have compression ratios of 11:1 + over here on pump fuel. On a cast 4V headed engine 11:1 would probably be the absolute max on pump, but alloy headed stuff 11.5:1 is not uncommon over here anymore. To my understanding our fuel over here may indeed have a higher octane rating, but apparently compared to your fuel in the U.S it's totally crap because it apparently has a very fast burn rate, which in turn causes higher combustion temperatures. Like when you say about 91 RON fuel apparently it equals out to around our 95 RON fuel and your 93 is basically our 98. Before we got 98 in any decent sort of quantities (early 00's), our premium use to be 95 and there were quite a few street engines running around the 10.5:1 mark without too many problems and since then a lot of massive things have happened with automotive technology. But still nice to see a 9.5:1 engine making fairly decent power and torque (done something similar years ago, but with 73 cast 4V OC heads)

 

[c9zx]

Great flat tq curve Chuck, gets over 450tq early too. Nice build.

Thanks. For the money spent I think it turned out good. It does over power the stock chassis tremendously. As it was a show and go build I didn't want to add sub-frame connectors and Cal-Tracs. If I keep it, they may have to be added. Chuck

Great build Chuck, very nice flat torque curve, the thing would pull like a train. One thing I really like about your build is that it's a solid flat tappet cam. The amount of people that go on about rollers and how great they are (which they are) but shut up very quickly when shown great figures made with a flat tappet cam. Those 4V's you used on your build were the intake ports left untouched or filled on the floors. I absolutely love using factory cast iron heads and make big power, especially against the Chevy guys. The guy I worked for years ago, in a full weight XY Falcon (all stock interior with ANDRA spec cage, factory panels) standard rear wheel arches (bloody tight fit getting the slicks in) It ran a 380ci stock cast block and 4V CC heads, C4 trans braked auto, 9 inch diff with 4.56 gears (pretty sure) this thing ran 9.5's in this configuration. It was hilarious at the 02 Winternationals, his car was getting a pretty serious reputation around the country. Had all these southerners coming up checking the car out, we stood back listening to the comments of people looking for a lightened car (fibreglass panels, lexan windows etc) and coming away scratching their heads finding a factory based car. Also I find it interesting about what compression ratios you guys run because you have dramas with detonation. We have compression ratios of 11:1 + over here on pump fuel. On a cast 4V headed engine 11:1 would probably be the absolute max on pump, but alloy headed stuff 11.5:1 is not uncommon over here anymore. To my understanding our fuel over here may indeed have a higher octane rating, but apparently compared to your fuel in the U.S it's totally crap because it apparently has a very fast burn rate, which in turn causes higher combustion temperatures. Like when you say about 91 RON fuel apparently it equals out to around our 95 RON fuel and your 93 is basically our 98. Before we got 98 in any decent sort of quantities (early 00's), our premium use to be 95 and there were quite a few street engines running around the 10.5:1 mark without too many problems and since then a lot of massive things have happened with automotive technology. But still nice to see a 9.5:1 engine making fairly decent power and torque (done something similar years ago, but with 73 cast 4V OC heads)

Roller cams have a place but, when not needed to reach the goals of a particular build, the money is better spent elsewhere in my opinion. This was a "street" build from the beginning, hence the lower compression ratio and street cam. I would have liked to have more lift but I also wanted it to live long in a street environment. So the the profile is not as intense as it would be with a .600+ lift cam. Having driven the car for a while, I could have run a little more compression (10:1) but I have no confidence that the quality of the gas will maintain it's current quality. My area is one of the few that still has 100% gasoline still available. Thanks to uninformed voters, legislators, and executive branch agencies, oil companies are forced, by the EPA, to buy X amount of ethanol to blend into "gasoline". So I built it on the conservative side.

The intake ports are not "stuffed" but the heads are mildly self-ported with the use of a friend's flow bench

In the states, the RON+ MON/2 method is used for octane ratings. The attachment show what is used around the world. http://en.wikipedia.org/wiki/Octane_rating

I finally found another set of 4V CC heads at a reasonable price and I intend to start building them for use on an old 405CID stroker I built about 22 years ago. I used the heads from it to build the 408 in the Mach 1. It also has a flat tappet cam. We'll see what it does.

It is great fun to compare outcomes with my Chevrolet friends, at least for me. I made 30 HP and 20 TQ more than a friend's 408 AFR headed, 13:1, solid roller cam SBC. Chuck

 

[Mark White]

Hey Maverick 351,

I have not dyno'd my 351 c, but I think its maybe around 500 or 600 HP. Its a almost stock Boss 351, running 10.7:1 compression, but with a Competition Cams full hydraulic roller, with similar specs to the stock solid lifter cam, but a little better. 2 1/2 inch stainless exhaust. It has a Paxton Supercharger, running 5 P.S.I. of boost, and Ram Air. Boss 351 did not come with A/C. This one is a "M" code, rebuilt to the Boss spec. with the correct intake, dual points etc. So, maybe try building it to a stock Boss spec. use a correct Paxton, add a roller cam, do the oil system upgrades, and you are there! Rev limiter would be good. I am sure there are more knowledgeable people on this site who will correct any errors in my recommendations. Good luck, take your time, it is worth it! There is no substitute for that monster power, roar, and acceleration! I have uploaded a picture of mine for you to check out, if you would like, Mark

 

[Mister 4x4]

My first question is: why would anyone want to push a 351C to make more than 400-450hp for a street car? Not that there's anything wrong with it, mind you - I'm just curious. 680 in any street car is just ridiculous, without some kind of traction control or regulation, you pretty much just have a tire-burning, out-of-control road missile.

Driving a car a few miles just to run it hard and hoping to drive it back home for the sake of teaching the local ricers a lesson just seems a little... juvenile (for lack of a kinder word) to me. Especially, given the terminology used of "street racing," and all the potential for bad things to happen along the lines.

If that's your goal, and again I'm not one anybody needs to seek any kind of approval or authorization for such a thing, then I would consider starting with a big-block and go from there - it certainly opens a lot more doors and options for making big power. Prior to getting the engine to the numbers you're looking for, I'd consider building the rest of the car to handle said power first (brakes, chassis, steering, suspension, electrics, fuel containment and delivery, driver safety, transmission, rear-end, etc.). It's better to have the car ready for putting in the power, than putting in the power and never get the car ready to handle it... because we all know the first thing to be done once the powerplant is in is to make a few test runs to see if you got what you wanted... and without the car being ready to control that power, you run the risk of ruining your project before you really get to enjoy it.

OK - I guess I'm done with my "out-of-left-field, old-man rant." Good luck with it, whatever you decide to do.

 

[will e]

Hey Maverick 351,

I have not dyno'd my 351 c, but I think its maybe around 500 or 600 HP. Its a almost stock Boss 351, running 10.7:1 compression, but with a Competition Cams full hydraulic roller, with similar specs to the stock solid lifter cam, but a little better. 2 1/2 inch stainless exhaust. It has a Paxton Supercharger, running 5 P.S.I. of boost, and Ram Air. Boss 351 did not come with A/C. This one is a "M" code, rebuilt to the Boss spec. with the correct intake, dual points etc. So, maybe try building it to a stock Boss spec. use a correct Paxton, add a roller cam, do the oil system upgrades, and you are there! Rev limiter would be good. I am sure there are more knowledgeable people on this site who will correct any errors in my recommendations. Good luck, take your time, it is worth it! There is no substitute for that monster power, roar, and acceleration! I have uploaded a picture of mine for you to check out, if you would like, Mark

Boosting a 10.7 with even 5lbs seems like a recipe for disaster (or at least a lot of pinging). I had a Paxton bracket for years but got rid of it when I found the tripower because boost and vacuum operated carbs (or secondary's) don't mix. I would love to see how you got it to work with the ram air as well. SOunds like a really cool setup that should put out some serious power.

 

[rocket366]

+2 @ Mister 4X4

 

[jgonzo]

Hey Maverick 351,

I have not dyno'd my 351 c, but I think its maybe around 500 or 600 HP. Its a almost stock Boss 351, running 10.7:1 compression, but with a Competition Cams full hydraulic roller, with similar specs to the stock solid lifter cam, but a little better. 2 1/2 inch stainless exhaust. It has a Paxton Supercharger, running 5 P.S.I. of boost, and Ram Air. Boss 351 did not come with A/C. This one is a "M" code, rebuilt to the Boss spec. with the correct intake, dual points etc. So, maybe try building it to a stock Boss spec. use a correct Paxton, add a roller cam, do the oil system upgrades, and you are there! Rev limiter would be good. I am sure there are more knowledgeable people on this site who will correct any errors in my recommendations. Good luck, take your time, it is worth it! There is no substitute for that monster power, roar, and acceleration! I have uploaded a picture of mine for you to check out, if you would like, Mark

Mark, you need to get a video of this thing running......nice job by the way. Would love to see/hear it running and revving!!!