Missouri Horsepower

[Larry P.]

The horsepower on my Missouri title for my 60 is listed as 51. They use some sort of pro-rated way of designating the horsepower from the true HP to the titled HP.
What HP is on the Missouri title of other 60 owners? By comparing numbers I might be able to figure out what it was originally. It has a 6500 red line tach and a single four barrel. (I know thats wrong) I believe the tach is original.
Larry

[Ken Robb]

Re: Missouri Horsepower

My original MO title application for my 300HP 65 is shown as 51. I forget now what the formula or chart that they used. I might be able to ask some of my in-laws in MO if we don't find out an answer here.

[Brian McHale]

Re: Missouri Horsepower

Larry, I have some MO DMV HP#'S for you. My 67 327/300hp shows 51 HP. I have info on a couple more that show 57. I also have one that shows 48. The 327/300 was the base engine in 67 so the 48HP rating dosen't make sense.

[Wayne M.]

Re: (Federal) Taxable Horsepower (MSO)

Has nothing to do with the state of Missouri. It's derived from a formula (John Amgwert provided it in an old RESTORER) and is related to bore and stroke, if I'm not mistaken, and NOT state of tune. All 327's had 51.2hp on their MSO (Manufacturer's Statement of Origin); all 427's had 57.8hp. The 396's were slightly less, and the 454's more. So you can prove the displacement of the original motor, but not the manufacturer's advertised horsepower rating.

[Doug Flaten]

Re: (Federal) Taxable Horsepower (MSO)

I always assumed the taxable HP was something to do with a net HP vs a gross HP rating or for powertrain losses or something like that. Was the taxable HP actually used for some sort of tax purposes on registration?

[Duke W.]

Re: (Federal) Taxable Horsepower (MSO)

"Taxable horsepower" is a function of BORE and the number of cylinders. Stroke is not included in the formula. It was used in the prewar years by some states to determine the annual vehicle tax, but was mostly phased out by the sixties. I think it was also used (or a similar formula) in the UK, and is one reason why both American and British pre-war designed engines were decidedly undersquare.

The actual formula is: ((No. cyls.)(bore)**2)/2.5.

This formula and the result for the 4" bore 327 is listed in my '63 AMA specifications. A 350 would also be the same 51.2 taxable horsepower. The 396 would be slightly less than the 427 and 454 because of the 396' smaller bore.

This formula actually has some technical merit. All other things being equal two engines of different stroke will make about the same peak power, but the longer stroke engine will make peak power at lower revs (corresponding to the same mean piston speed that the short stroke engine makes peak power), but the long stroke version will make more average power over the useable rev range.

Duke

[Larry P.]

Re: (Federal) Taxable Horsepower (MSO)

Why would a 283 be 51 HP?
Larry

[Duke W.]

Re: (Federal) Taxable Horsepower (MSO)

For a 283: 8(3.875)**2/2.5 = 48.05

For a 327: 8(4.000)**2/2.5 = 51.20

Duke

[Warren F.]

Re: (Federal) Taxable Horsepower (MSO)

My Illinois title shows 57.8 for my '71 LS6 coupe

[Chas Kingston]

[mike yager]

Re: (Federal) Taxable Horsepower (MSO)

Ah yes, Fortran. Another usable skill learned in college. I never used Fortran or the punch cards I learned programming on again after college.

Reminds me of a few years ago talking with a young lady at work fresh out of college. She had graduated the previous year from Radford University in Virginia. When she found out I graduated from Rutgers University, she asked me what my email address was when I was in school since both Rutgers and Radford have the initials "RU". She could not understand that we did not have email or internet access as a student in the 70s. She never heard of punch cards. Forget to ask about Fortran.

[Wayne M.]

You're correct; (per Duke) stroke has ......

.... nothing to do with the calculation, as your 454 bore is the same as a 427. I was dredging from almost 60-year old brain cells. Gonna write that formula down somewhere (then I'll forget where).

The other identical pair will be the 327 and the 350 cu.in; both with (taxable) 51.2hp due to the 4.00 inch bore.

[Duke W.]

Re: (Federal) Taxable Horsepower (MSO)

So how do you type in that "superscript 2" to indicate a square function, so I don't have to revert to the ancient FORmula TRANslation notation?

Duke**2

[Tony H.]

[Doug Flaten]

Re: (Federal) Taxable Horsepower (MSO)

Thanks for clearing that up Duke. Like I said, I previously thought that taxable referred to losses, and that it meant a 283 engine with a 270 hp (gross) rating would net down to about a 220 hp rating by today's standard. I am not old enough to have registered cars using the taxable HP, but I am old enough to have learned and used Fortran briefly. Fortunately, I only had to use a slide rule during my freshman year of high school before calculators rescued us all. Apparently I have not been savvy enough to know how to type exponents either. It sure would be easier if they took a lesson from the calculator folks and add another shift or function key.