HELP PLEASE.....

I went to the drags the other day with my supposed 550 hp. small block. 1.80 60 ft. 11.92 112 mph.whats going on..
71 demon 3250 lbs with me frame connectors, 4500 flash stall,727 reverse pattern.
340-373 forged internals 13-1 compression W2 heads flow 315-250cfm
1 5 8 headers 28 tire spool..c 14 race fuel mixed 50 50 super unleaded

What am I missing timing @ 32 degrees..

Plese help me I dont know what to do to get my M.P.H.

Thanks alot any info would help.

What carb.............

Do you have a fuel pressure gauge on it?

What fuel pump and line size?, gear ratio?

what rpm are you shifting at?

What gears? What rpm did it launch at? Did you check for wide open throttle?

Header change.... quickly.

1 5/8 full length tube headers will not support your 550 hp potential.

Sounds like your currently more like at 425-440hp.

Wow you guys are fast,I will try to answer everyone.
Carb 650 dp holley 55 power valve 78 jet front 82 rear. fuel pressure I think 7 psi holley blue pump no guage.. Fuel line 3-8 ,I shifted at 6000, and launched at 2000 rpm..Rear gear is 4,10 dana 60 no pinion snubber nosedown almost 10 degrees.

Carb is way too small. Have you tried different launch/shift points yet?

How do you "think" fuel PSI is 7#, without a gauge??

I assume the motor is fresh? I'd do a leak down test anyway to start at the basic step one and go from there.

There are ALOT of things that make up a good running car. BUT...it only takes one or two seemingly small things to really hurt the performance.

You need a fuel pressure gauge and the pressure is usually based on the needle n seat size. Bigger = lower pressures and visa versa and a 650 wouldn't be my first choice along w/10 degrees of pinion angle............

The headers aren't going to kill that much power. I have been 10.70's in a heavier car with basically same size header .
Sounds like something in the combo is way wrong, making it be a dog.
My heavier car with a 318 runs about like what your seeing, what camshaft, and where did the heads come from?
Even the carb shouldn't kill that motor all that much. Should run well into the 10's easily.

More RPM, more gear, more carb to start. What intake and cam?

Depending on your cam, 13.1 W2 small block should probably RPM well past 7,000. Deeper rear gear will get you there faster, probably need at least 4.30 or more. Small blocks need gear and converter until you start getting over 400 CI where they produce enough torque.

650 carb is too small especially for your potential RPM, should be at least an 850.

Timing is a little conservative for race fuel, might try 34-36 total?

Also, pinion 10 degrees nose down is too much, should be 4 down, the car is fighting itself off the line which is reflected in your 60 ft.

Maybe a little more info on the chassis? Rear tire size and inflation? Rear springs? Chassis stiffening? Front end setup? Shocks etc?

Timing has nothing to do with race fuel regards what you are inferring.
I ran a stout W5 combo on 112 that made best power at 32 degrees, tried it everywhere else, 32 was best. Most good, well done heads don't want much timing, no matter the fuel.
The heads on my current car are supposedly very well done( engine masters engine) and also like 32.... I have had them everywhere between 30-38... 32 best power.

Can you explain why?

Like I said above, a good head doesn't need as much timing as a bad head. A very good combustion chamber contributes to the fuel getting burned quicker and more efficiently.
I gave two examples of heads I have had/ have( both with excellent chambers) that make peak power with 32 degrees timing and completely different fuels.

1.80 60 ft., Your bogging big time. It may not feel like it but you are. Your mph is good for a 11.75. Your not getting out of hole, fix that first. Timing needs increased to more like 34* to 36. Test it to be sure. Carb needs some tune as well for sure. All just common stuff for a new combo, it will come around if it was truly dynoed at 550 hp. Your 4500 stall speed is low for a sb as well with that hp.

Lol.... Mph is WAY, WAY off. A 13 to 1 370 inch motor with 300cfm heads should run 120 falling out of a tree with nothing going correctly. Even with a doggy 60 foot the car should still make way more mph than 112. It's likely a lot of little things, but even if running the same timing it made 550 on the Dyno with( which I would assume is the starting point) something else is super out of whack that isn't a simple tweak. It isn't making much over 400 horse based on 112 at that weight.

Yes, MPH is way off as well. But hey if it cant get going till 100 ft + out its not going to get the mph the hp should reflect.

At 3250 112 is more like 450hp. I would like to see the mph Split between the 1/8th and the 1/4 Can you post that OP. Should be around 24 mph difference.

My motor made 477 at engine masters. With a bigger solid cam..... now has a smaller hydralic cam. I have been almost 113.5 At 3415 pounds with power steering and other stock accessories. Guess based on your calculations I have got everything out of this thing it's going to get. I honestly thought about 30-50 horse are unaccounted for( after power robbing accessories are accounted for) was hoping this thing would go 116-117.

Btw, the bad 60 is going to effect ET much more than mph. Much more. I have a buddy who has a 4400 pound Charger with the 475 horse hemi. It runs 110+ mph at that weight and the 60 is as bad or worse than the OP.
I remember doing a huge wheel stand at Norwalk a few years back. Otherwise normal pass that day was 9.95 ish at 133.5/134mph. I lifted an instant when the car landed, ran 10.96 but it still ran almost 130 on that pass. Mph takes power, ET takes a lot of stuff. The OP isn't making any power.

Right up front I apologize if this offends you, but make sure the carb is opening fully when the gas pedal is fully depressed. Happens more than you think, what is the saying? "Don't ask me how I know..."

Fix the pinion angle. 4deg is plenty.

Put a fuel pressure gauge on it, adjust to 6.5psi, check/set floats.

Make sure it's getting full throttle.

Take it to a chassis dyno for a few pulls. Use a shop that can monitor the a/f ratio and make sure that's at least "close".

Go back to the track, try it again.

What makes you THINK it's 550HP ???

What cam do you have? Yes, with 13:1 compression and good flowing W2's you should make 550 without much trouble but not if it's got a puny broomstick cam (judging by the rest of the build I'm guessing it's not but you never know)