technical brain teaser:how does lil cube beat big cubes?

[jenavet]

anyone who knows me understands i am easily confused,but this one boggles my mind......both of these cars weigh the exact same and are professionally set up so that both combinations are ideally matched [ie gear ratio,converters etc] and both engines are making the horsepower that is stated[verified by a dyno.] both vehicles are run together at a dragstrip and traction on any part of the track is NOT an issue.

in one corner we have a 408 sbc on gas,4 barrell dominator carb...dyno says this motor makes 832 horsepower @7700 rpm and 621 ft lbs of torque at 6500rpm

in the other corner we have a 555 bbc on gas with 4 barrell carb.....dyno says this motor makes 923 horsepower @7400rpm and 758 ft lbs of torque @ 6200 rpm.

both vehicles are exactly the same weight,body style,have no traction issues and combinations are set up perfectly......the 408 runs a couple hundreths and 2 mph faster than the 555.....how does this happen?? would the dyno sheet tell the story? the 555 makes gobs of torque up to 7000 rpm and then falls fast...the horsepower is low then zips up fast to peak and then falls off quick......the 408 torque peaks at 6500 but falls off real slow...the 408 horsepower curve looks real flat...it peaks at 7700 but dosent drop really at all till about 8300........this is the only area i can that can explain this??

 

[warren s]

Going strictly by the information posted, it would seem the BB should be faster, the dyno curve would tell if one or the other is putting down power in an area that more closely matches the gear ratios chosen.

By the numbers you posted, I would not put the same gear ratio in each car.

Driver skill is also a variable.

 

[jenavet]

the 408 was run with 4.30 gears and the 555 ran with 4.10 gears

 

[SoLow]

Is there any differance in total weight in these cars? IE front to rear ratio as a BBC is a few lbs.heavy than a SBC. A couple of pounds can cost a tenth or two.

 

[wishuwerehere82]

Here's an interesting primer in HP and TQ to read that may help explain.
http://vettenet.org/torquehp.html