[pancho_villa]

In the modern rating how much horsepower does a 66 225hp "A" code have? I don't care about modified.

My guess is about 150.

 

[Meyer65]

I think generally it is about 80%
so .8x225=180

This would of course be operating under the assumption that the 225 stock hp rating was accurate.

 

[JohnnyK]

Flywheel no doubt.. I thought 80% was optimistic? I don't even trust the 5.0 HO 225 number..

 

[Meyer65]

I thought you lost about 80% from the flywheel to the wheels. This is just what I have hears. I actually have no experience in the matter so I can't say for sure one way or the other if 80% is accurate.

 

[smithers]

Between 125-130 HP at the rear wheels. Mustang Monthly put an original A code car on a dyno and that's what they got. They then hopped it up a little at a time to see what adding on various items did. I don't have the link, but you may find it on their site.

 

[Guest]

Also, consider that the modern hp rating calculation is based on "net" hp, which means with all the accessories attached whereas the old way was without any accessories.

Only true way to know what your own car is producing is to put it on a dyno.

 

[JohnnyK]

I thought you lost about 80% from the flywheel to the wheels. This is just what I have hears. I actually have no experience in the matter so I can't say for sure one way or the other if 80% is accurate.

Oh yeah.. As charles said though, they also measured it without any accessories, etc..

 

[RagTop]

Yeah. A buddy of mine with a mildly warmed 67 289 4V pulled 145 rwhp on a dyno. 145 rwhp/.80 = 181 fwhp. Based on that, 66EmberglowGTConvertible's 125 - 130 rwhp magazine number sounds pretty reasonable for a stock 66 A code, so the resulting fwhp would be 156 - 163. Sort of puny compared to today's engines. If we believe our numbers, than the net rating of 163 divided by the gross rating of 225 would result in the net being 72.4% of gross. That would mean that my 69 302 2V which was rated at 220 hp in the day, only put out 159 hp and my 427 4V Corvette rated at 390 hp actually only put out 283 hp in net horsepower. That would explain why my Z28, which laid down 318 rwhp, is so much stronger than the Vette. Let's see....318rwhp/.84 (modern automatics are more efficient)= 379fwhp. This all goes out the window when you realize that Detroit has consistently lied over the years about gross and net fwhp to suit their needs. Like the 428 SCJ being rated at 335 gross fwhp when it was clearly stronger than that or GM rating my LS1 Camaro at 305 fwhp to keep the contemporary LS1 Corvette owners happy (their nearly identical LS1's were rated at 345 fwhp.)