Horse Power

[Douglas]

Since we’re talking cams and intakes and stuff. Is 200hp out of a 251 spit motor out of the question?

[dpollo]

I would say that it is.    This  engine was never intended to put out that kind of horsepower and even if it could be obtained,  the crankshaft would likely fail near #6.

Even stockers can develop stress fractures in this location.   However , overall performance  of a 251 can be improved  and lots of people have done it but reliability declines significantly the more you try to squeeze out of it.   

It might be fun while it lasted.

[Ajgkirkwood]

1 hour ago, dpollo said:

I would say that it is.    This  engine was never intended to put out that kind of horsepower and even if it could be obtained,  the crankshaft would likely fail near #6.

Even stockers can develop stress fractures in this location.   However , overall performance  of a 251 can be improved  and lots of people have done it but reliability declines significantly the more you try to squeeze out of it.   

It might be fun while it lasted.

I thought these were tough motors from what i read on the forum. If some one can confirm this as i was planning to hope up my motor. But if i spend 100s to 1000s and its gonna fail i dont want it

[Uberchin]

Swap in a slant 6 or hemi 8 if you're going for HP; money better spent instead of killing your flathead.

[Douglas]

All good reply’s. Thanks folks. 

[55 Fargo]

Well yes and no on the 200 hp, a 250 rated at approximately 116 hp and slightly higher in big truck engines in the late 1950s.

Okay so add the tri carb intake, headers/dual exhaust, high compression head, lighter weight 3 ring racing pistons, and you could climb to 175 hp and whole lot more torque, RPM and umph.

Now 200hp, might be a little tough  on a mild build, going all out might not.

A 265 might yield this 200 bench mark a bit easier.

The type of build I describe on a 250 should be noticeably more powered then a tired stock 250.

Slant 6s can be made to go like a " bat outta hel", 11 second quarter mile cars are not outta the question, and a 1961 Dodge Lancer with a 225 hi perf engine taught a Hellcat Hemi a lesson on the strip, don't believe it google it on You Tube...

You wanna make power, seriously give George Asche a call, he will tell you the straight on this... PS waking your 250 up,in a mild build,  will most likely give you all you want.

[greg g]

In 1954 Kaiser wanted to be able to tout added HP like Olds, Caddy and others that had all switched over to V8 engines.  They put a supercharger on their 228 cubic inch. 6.  Factory engineers could only pick up around 20 HP. Even Hudson's highly developed X7 version of their 308 cubic inch six, basically a slightly detuned NASCAR engine was putting out 165.  That seems to probably be the epitome of L head hp.  Adding 40 HP to a smaller engine though probably possible would not be a practable unit for the street. Not to mention costly.

[55 Fargo]

7 minutes ago, greg g said:

In 1954 Kaiser wanted to be able to tout added HP like Olds, Caddy and others that had all switched over to V8 engines.  They put a supercharger on their 228 cubic inch. 6.  Factory engineers could only pick up around 20 HP. Even Hudson's highly developed X7 version of their 308 cubic inch six, basically a slightly detuned NASCAR engine was putting out 165.  That seems to probably be the epitome of L head hp.  Adding 40 HP to a smaller engine though probably possible would not be a practable unit for the street. Not to mention costly.

And in 1954 the Chrysler Corp marketed there new V8s for big truck, the new V8 had slightly more HP than the 265 with factory dual carbs/exhaust, the 265 had a stock cam and head, so nothing was gained there.

Edited December 21, 2017 by 55 Fargo Spitfire

[Douglas]

39 minutes ago, 55 Fargo Spitfire said:

Well yes and no on the 200 hp, a 250 rated at approximately 116 hp and slightly higher in big truck engines in the late 1950s.

Okay so add the tri carb intake, headers/dual exhaust, high compression head, lighter weight 3 ring racing pistons, and you could climb to 175 hp and whole lot more torque, RPM and umph.

Now 200hp, might be a little tough  on a mild build, going all out might not.

A 265 might yield this 200 bench mark a bit easier.

The type of build I describe on a 250 should be noticeably more powered then a tired stock 250.

Slant 6s can be made to go like a " bat outta hel", 11 second quarter mile cars are not outta the question, and a 1961 Dodge Lancer with a 225 hi perf engine taught a Hellcat Hemi a lesson on the strip, don't believe it google it on You Tube...

You wanna make power, seriously give George Asche a call, he will tell you the straight on this... PS waking your 250 up,in a mild build,  will most likely give you all you want.

Thanks. 200hp was a number thrown out to get feed back. If a comfortable and reliable 150 is reality that would be great. Plus a 5sp will make a great cruzier. Looking like a will get ahold of George soon. Thanks again. 

[bob westphal]

The flathead Mopar crankshafts had a soft surface on the throws. You could actually scratch the surface with a wrench by accident. In my youth I drove a '47 P-15 sedan that I souped up. The engine was over bored to the max, Wiseco pistons, ported & relieved, Isky full grind cam, SCHAEFER light flywheel & clutch, Edmunds 10-1 high comp head, dual Edmunds manifold with Stromberg 97's, hand built six tube exhaust header run into a single collector box. I had the crank sprayed with hardner to hold the extra power. I have no idea of the HP rating but the car ran in the low 15 seconds in the 1/4. However the crank failed when was ran at high rpm for an extended time. That's why I installed a SL6 in my current coupe and automaticaly got an extra fifty hp.

Edited December 21, 2017 by bob westphal

[55 Fargo]

20 minutes ago, bob westphal said:

The flathead Mopar crankshafts had a soft surface on the throws. You could actually scratch the surface with a wrench by accident. In my youth I drove a '47 P-15 sedan that I souped up. The engine was over bored to the max, Wiseco pistons, ported & relieved, Isky full grind cam, SCHAEFER light flywheel & clutch, Edmunds 10-1 high comp head, dual Edmunds manifold with Stromberg 97's, hand built six tube exhaust header run into a single collector box. I had the crank sprayed with hardner to hold the extra power. I have no idea of the HP rating but the car ran in the low 15 seconds in the 1/4. However the crank failed when was ran at high rpm for an extended time. That's why I installed a SL6 in my current coupe and automaticaly got an extra fifty hp.

230 Offset Rods have anything to do with this Bob?

That engine sounded impressive though...

The /6 bottom end was not all that different from the 250/265 bottom end, correct?

[dpollo]

 I have heard that crankshafts were much improved from 1955 on as well as in earlier truck engines.

I have only once seen a failure in a 251 with the full flow filter and that was back in 1966.  On my own  stuff, I try to avoid undersize of more than .010.

[Matt Wilson]

I spoke with a gentleman named Steve Fowler, who runs a company called Power Wagons West, and he does some serious flathead mods.  I believe he said he has gotten 200 hp out of some of the 230's he has built, as measured on a dyno, at something like 4500 rpm, if I recall correctly.  He does some costly things to those engines to get this, which most of us would not be willing to spend, such as true blueprinting.  He's been doing this for a number of years, and I don't think he has had any complaints of failures from his customers, but considering his engines are going in Power Wagons, not race cars, they are probably not put through those paces all the time.  It's just an indication of the umph that these engines can produce.  And FYI - he uses D. Elgin Cams (not to be confused with Elgin Cams) for his cams.

[55 Fargo]

8 hours ago, Matt Wilson said:

I spoke with a gentleman named Steve Fowler, who runs a company called Power Wagons West, and he does some serious flathead mods.  I believe he said he has gotten 200 hp out of some of the 230's he has built, as measured on a dyno, at something like 4500 rpm, if I recall correctly.  He does some costly things to those engines to get this, which most of us would not be willing to spend, such as true blueprinting.  He's been doing this for a number of years, and I don't think he has had any complaints of failures from his customers, but considering his engines are going in Power Wagons, not race cars, they are probably not put through those paces all the time.  It's just an indication of the umph that these engines can produce.  And FYI - he uses D. Elgin Cams (not to be confused with Elgin Cams) for his cams.

Yah never heard of this outfit but kool.

Tractors pull way higher than 4500 rpm.

Heck my old 228 with its leaking cylinders and all spins to 4000 rpm.

George Asche and Tim Kingsbury know how to make power and RPM to 6000 RPM..

[greg g]

Where in the real world are you going to have a vehicle that needs to produce peak HP at 6000 rpm??? IsNascar going to have a vintage truck race division?  Making HP @high rpm and using it are very different and distinct things. The engine in my daily driver produces it peak HP a 6200, I don't believe I have had it that high except for a couple of very brief bursts.  Peak torque is at 4000.  Going down the road at 70 is 2100. Again where do you use this high rpm power???  Is this discussion about size matters or satisfaction?

[martybose]

Had to laugh reading Greg's comments.  My other toy is a BMW M Coupe, which has a engine that produces peak power at 7400 RPM and redlines at 7600.  It has so much midrange power that in over 60K miles I've driven it I don't think I've ever had it over 6500 RPM, and most of the time in street driving I shift it about 4000.  But I know that if I ever needed it, there's a whole lot of power up there for the asking.

Marty

[55 Fargo]

My Hemi Powered ram spins to 5500 RPM with ease, not that I do that often.

[55 Fargo]

1 hour ago, greg g said:

Where in the real world are you going to have a vehicle that needs to produce peak HP at 6000 rpm??? IsNascar going to have a vintage truck race division?  Making HP @high rpm and using it are very different and distinct things. The engine in my daily driver produces it peak HP a 6200, I don't believe I have had it that high except for a couple of very brief bursts.  Peak torque is at 4000.  Going down the road at 70 is 2100. Again where do you use this high rpm power???  Is this discussion about size matters or satisfaction?

Greg, exactly,  some of the Engines I am mentioning (  some owned by AoK Racing) are far from Street Machines, as well as the Tractor Pullers, so wicked high RPMs win them races/competitions.

Yes I am guessing my 265 build will most likely spin up to 5 grand, am I going to drive it like that, most likely not, but it will have a power band and capability outside of the stock range.

Going down the road  at 70 mph at 2100 RPM, that would be the lowest Im would spec for, think these engines might be happiest in the 2300-2500 rpm range...

In fact with some OD reductions and high  rear gearing, the notion of cruising at 60 MPH at 1600-1800 sounds good in theory but try that on a windy day, or going uphill for a few miles, bogging is inevitable.

 

Edited December 22, 2017 by 55 Fargo Spitfire

[dale]

On 12/21/2017 at 12:21 AM, Uberchin said:

Swap in a slant 6 or hemi 8 if you're going for HP; money better spent instead of killing your flathead.

Wondering if a later model Chrysler V-6 will bolt up to the stock trns.  I dont see sacrilidge in using a Chrysler V-6 in an old Plymouth.

[55 Fargo]

Just now, dale said:

Wondering if a later model Chrysler V-6 will bolt up to the stock trns.  I dont see sacrilidge in using a Chrysler V-6 in an old Plymouth.

Yah right... nice wish though

[wayfarer]

17 minutes ago, dale said:

Wondering if a later model Chrysler V-6 will bolt up to the stock trns.  I dont see sacrilidge in using a Chrysler V-6 in an old Plymouth.

...bolt-up....no......  Which v-6?    MaMopar has made plenty of them in the last 20 years.

 

Anything is possible if you choose to invest in the time and machine work.

[55 Fargo]

In this "Locked thread" there are videos of the AoK racing stock, and some others. Please enjoy and comment, possibly this locked thread can be integrated into this thread.

 

[Matt Wilson]

15 hours ago, 55 Fargo Spitfire said:

Yah never heard of this outfit but kool.

Tractors pull way higher than 4500 rpm.

Heck my old 228 with its leaking cylinders and all spins to 4000 rpm.

George Asche and Tim Kingsbury know how to make power and RPM to 6000 RPM..

 

Yeah, the 4500 rpm's is not the impressive part;  that's just mentioned as the rpm at which peak HP occurred.  Rather, the impressive part is the fact that 200 hp was achieved on this engine.

Edited December 23, 2017 by Matt Wilson

[dale]

On 12/22/2017 at 10:07 AM, 55 Fargo Spitfire said:

Yah right... nice wish though

I bolted up a 56 Plymouth V-8 to a 47 Ply trns once. I had an automatic trns so all I had to do was toss out the spacer bellhousing.  Clutch and all that worked.  Only had to put on floorshifter.  Donk know but sometimes they keep things the same for decades.

[55 Fargo]

7 hours ago, dale said:

I bolted up a 56 Plymouth V-8 to a 47 Ply trns once. I had an automatic trns so all I had to do was toss out the spacer bellhousing.  Clutch and all that worked.  Only had to put on floorshifter.  Donk know but sometimes they keep things the same for decades.

Have no idea on this, Sure but a whole different movie on the OPs question...