Dyno question

[Toro67]

I had my car dynoed this weekend and I have some questions:

First, I noticed that the HP and torque (in ft-lbs) cross at around 4100 RPM. Should this cross at 5252 RPM?

Second, this engine was rated at 375HP and 390 ft-lbs from the builder (FWHP). It dynoed at 240 hp and 300 ft-lbs (RWHP). This is a 350 ci, iron heads, 750 cfm carb, mild cam, 32* total advance, 10.2:1 comp, 2.5" exhaust through glass-packs, flowtech shorty headers (1.5" pri and 2.5" coll) , electric fans, 700R4, steel driveshaft, 3.73 gears, 10 bolt, eaton posi. Does this sound right? This was on a mustang dyno.

I know I could advance the timing to 36* and I need a better exhaust, but I still think the 375/390 from the builder is a bit "optimistic".

[blown69nova]

Depending on what kind of iron heads and which "mild" cam is in it, 375 ft/lb is possible. If you are talking unported GM iron heads and say a Performer cam, you would more likely see about 300 hp.
From what I hear, Mustang dyno's are more conservative than a dynojet.
Steve

[68Formula]

Did they put two different scales for torque and hp? That is the only way they would not "cross" at 5252rpm. For example the torque scale goes from 0 to 600 ft-lbs and the hp scale goes from 0 to 400hp.

[Karch]

HP=T x RPM/5252

[Toro67]

Did they put two different scales for torque and hp? That is the only way they would not "cross" at 5252rpm. For example the torque scale goes from 0 to 600 ft-lbs and the hp scale goes from 0 to 400hp.

You're right. I just noticed that they used different scales. So at 5252RPM, HP=torque (in ft-lbs).

My engine builder won't give me the cam specs. These engines aren't dynoed in the shop either; we had to first fire and run the engine in.

Oh well, the car is running good now, that was my biggest concern. I'll figure out how to get more HP later.

[My427stang]

He wont give you the cam specs on a mild motor? Thats pretty goofy, certainly a good running small block, but man its not a secret class racer.

Which heads? Depending on chamber shape and quench you could probably use a little more timing (assuming its not a very efficient chamber)

Also, which intake?

You have a lot of ground to make up to get to his numbers, but its not impossible depending how stingy the dyno is.