The dyno -a good dose of truth serum

[slugish]

MY SON FINALLY TALKED ME INTO GOING WITH HIM TO HAVE MY TRUCK DYNO'D IN RICHMOND VA. ABOUT 75 MILES FROM HERE. TALKIING ABOUT A HUMBLING EXPERIENCE (SORT OF WISH i HADNT GONE ) 300 TORQUE --240 HP . i HAVE A 400 bored 40 over , 268 cam Ithink , flat top pistons . long tube headers. msd 6al , airgap intake , 750 holley, . I knew Ididnt have a monster engine but Ithought I had a little more than that . The culprit that is holding me back is my cast heads > they have been ported & polished -3 way valve cut & milled . 30 , but according to the guy at the dyno my heads suck >really holding me back <

Just wanted to share this< Oh afterward we went to the strip .Imade 2 passes --a 14.27 at 94 mph. & a 14.56 at 93. Not too bad for a 240 hp , heavy square truck . What a way for a 64 yr old to spend his Friday

[slugish]

Oh Ive started saving for some aluminum heads . !!

[3r!c84]

that sounds like my motor(400) fastest run was a 13.90 tho. but yes the heads are holding me back too

[Restrorob]

Originally Posted by slugish

What a way for a 64 yr old to spend his Friday

Hmmm...... I see a pattern here......

Maybe when you get those new heads you'll only have a "slugish" user name !

[N2TRUX]

Originally Posted by slugish

..... What a way for a 64 yr old to spend his Friday

I would say it's a pretty darn good way for a gray hair to spend the day...

[77BBGMC]

It’s funny you mention “humbling experience”. I took my engine in last week and run it on a dyno. The guy ask me what my expectations were and stated that the majority of the guys that bring their engines in for dyno are humbled. Knowing how my luck is I went in with low expectations, fortunately I left there feeling pretty good.

[Hazieview]

I have a sb400 with pretty much the same upgrades as you. I'm also running cast heads.

My machine shop told me I'd be pushing around 580 Torque at least...

From what you said your truck dynoed at I am going to be very very very let down after I spent 6 grand on my engine if it performs the same way....

Not a bad number but 300ftlbs is a long ways from 580ftlbs that's for sure....

[BigBlocksRule]

RWHP is going to be down 15 - 20% from flywheel.
It takes big heads to make big horsepower, concentrate on torque and you can't go wrong with a heavy truck with all the aerodynamics of a barn door.

[jrcaprai]

Popular Hot-rodding has an article this month about Chassis dyno's!
I would not get too caught up in the numbers apparently they can vary quite a bit...
their car tested 487, 564, on Chassis dyno's and 675 on an engine dyno... there are a lot of variables, Calibration, the Operator, tires, Torque converters, What weather conditions they are tested at... etc...
the true test is at the track...

if you run the calculator below it comes up with 272 at the rear wheels to do a 14.27
So thats about 345 HP at the Crank... which is what you'd expect with stock heads
http://www.wallaceracing.com/et-hp-mph.php