Now, I posted this on the Camaro site, and got some very satisfying answers, but wanted to post this here too for the heck of it.

My friend has a 406 in his '68 Camaro 'SS'. He bought it from a mechanic (that he always calls his mechanic) and was told it's 550HP (surely this was crank at least). He doesn't really know anything that's in it, except that it's a solid lift cam and has the '69 Z/28 heads on them. Even still I'm 99% certain there is no possible way for the engine to make that much power, running on 93 octane (he says his CR is 11.5:1). His 1/4 in an ~3400# car was only 97mph@13.88 seconds, with a 3.73 rear and a TH-350, and Mickey Thompson street slicks...

Is my skepticism on those heads making that much power as warranted as I think/am told?

97 mph at 3400lbs is 297 rwhp...the heads are probably 186 castings..they are capable of making 450 HP with some work..right now hes around 350

My spare motor has 3991492 heads they are over the counter 64cc angle plugs. That motor chasies dynoed at 406hp with a 3.48 stroke.

Originally posted by bigjimzlll:
97 mph at 3400lbs is 297 rwhp...the heads are probably 186 castings..they are capable of making 450 HP with some work..right now hes around 350 Sounds reasonable enough. The biggest problem i had with his 550 claim was the fact that his trap speeds were so low.

I'd say that it is closer to 260 RWHP and 310-320 flywheel. He's not making that many ponies.

He'd be running around 11.0 and 120+ MPH with 550 HP (certainly many variable there). I run that at 3550 lbs and make 440 RWHP with spray.

Originally posted by BB485:
My spare motor has 3991492 heads they are over the counter 64cc angle plugs. That motor chasies dynoed at 406hp with a 3.48 stroke. what cam and compression etc on that engine? I run these heads fully ported on my 383 just curious thanks!

I say nay to the 550 hp claims with a 97 trap speed!

Originally posted by bigjimzlll:
97 mph at 3400lbs is 297 rwhp...the heads are probably 186 castings..they are capable of making 450 HP with some work..right now hes around 350 Closer to 300 engine HP not rear wheel HP
If you are using the online calculator I think you are it is WRONG.
I have emailed them about this a couple of times but apparently it isn't important as I have recieved no replies.

A freind of mine had his circle track 327 at dyno'd- 532HP with 186 castings with major port work and larger valves.

He was having major traction issues off the line. In fact the guy in the tower at the midnight drags said "dude in camaro, when your rear tires start spinning, let off the gas." If he has that little horsepower I would think especially with ET streets he'd have plenty of grip.

However one thing to note it was a fairly humid night, so i dont know how much that would affect performance, especially with a carb.

for what its worth I have had 3.0 60 ft times before spinnign to 1/8 mile and still trap 107 mph smile.gif and I am no where near 550 hp.

How about this. I had a 355 with those heads, ported by myself with a 204/214 cam, 9:1 compression, stock converter, 2.73 gears, at 3450 lbs and ran 13.9's at 100 MPH with street tires or slicks. I probably had around 300 HP.

Originally posted by Wolfplace:
</font><blockquote>quote:</font><hr />Originally posted by bigjimzlll:
97 mph at 3400lbs is 297 rwhp...the heads are probably 186 castings..they are capable of making 450 HP with some work..right now hes around 350 Closer to 300 engine HP not rear wheel HP
If you are using the online calculator I think you are it is WRONG.
I have emailed them about this a couple of times but apparently it isn't important as I have recieved no replies. </font>[/QUOTE]I didn't use the one your thinking of..I used Virtual Engine 2000...the online one was down for some reason(maybe fixing it.. smile.gif ) If the online one is wrong..they're all wrong..ive tried them all with the same input and got the same output

Jim,
Virtual 2000 supposedly gives engine HP I believe, all I can tell you is to do a few calculations & see if it makes sense to you.
If that calculator was right a 204 mph Pro car woud be making over 1500 rear wheel HP assuming about 20% loss??
Here is a little formula that has been around since at least the 70's & was used by Chrysler Corp. in their drag racing program & written up in the American Journal of Physics in 1973
HP=(.00426*MPH)cubed * WGT
I add about 50 HP to the number because MPH is measured differently now than it was in the 70's.

So,,,,,,,.00426*97=.41322cubed=.07056*3400=240HP
Add 50 to be nice,,,290HP
I find this formula works pretty fair until you get into some of the very hi end cars like Pro Stock. I find with cars like these it will give you a higher HP number than you usually see, especially adding 50HP.

This formula might be old but I believe most of the laws of physics still apply,,,,,,unless of course you are using that "Good LA air" when you dyno :D :D

Mike,
I bow to your wisdom...i hope to learn something new everyday...so today was a good day :D Thanks

"This formula might be old but I believe most of the laws of physics still apply,,,,,,unless of course you are using that "Good LA air" when you dyno"

I can never figure that out, my car chassis dynos about 70 HP shy of what a similar engine dynos in "LA air", but it is a second quicker at the track? ;)

I've got the same formula I think in my thesis and have one for both 1/4 ET and MPH to calculate flywheel HP and you can enter MPH to calculate theoretical best ET. They seem close and do not exaggerate the numbers. If anyone wants them I can post them.

Hi Doug,
I have those around here somewhere but I tend to stay away from the ET ones. They are real good on a well set up car & a good run but just too many variables.
The speed will not change much from a good run to a bad one within rerason but ET can be all over the map.
The other thing you always need to take into account is weather & altitude.
And of course the alignment of the moon & stars :D :D

Just for info I have found that using .80 for speed & .64 for ET works very good for converting 1/4 to 1/8 speeds & times.
Multiply for 1/4 to 1/8 & divide for the opposite

Hey Mike,
I agree. The one formula is nice to see what your car should do from MPH if traction and gearing are set up right.

Let's the less informed know what it should do when they stuff that BBC in and run it with street tires!