Frnknsteen's '67 Barracuda

Well,... I gave the car a tune-up (Accel cap & rotor and Champion RJ12Y plugs) and adjusted the timing (33 all in with mechanical only) and idle circuit (highest vacuum on gauge) best I knew how. Decided to take the car to the chassis dyno at a local shop to let them see what it had, verify the A/F ratios and find the right timing setting for how it is sitting now.

As I said before, I bought this car from the previous owner who had done a lot work to it, but decided family needs came first and decided to sell. I wasn't able to get any of the motor specs from him other than him saying the engine shop did some machining and he put in a bigger Competition Cams camshaft in it. I have no idea what the cam is, what pistons he is running, or any idea of what the compression ratio might be. I CAN say it runs good. Little bit of a lope to it at idle, and is fun to drive, but like a lot of us,... I can't say it wouldn't hurt to have a little more uummpf behind it. Like I said, it runs pretty well, but as the shop owner said,... "It just seems a bit lazy".

Having little information on the condition of the motor, we decided we didn't want to push it, so we limited the runs to <5000 RPM. First run was just to get a baseline and gave us 245.8hp/324.4 ft/lbs. The tech didn't like the little A/F dip in the midrange where it was running a little rich, so he sprayed a little cleaner down the air tubes and ran it again. The A/F ratio seemed to level out on the next pass and hp/tq both increased. As I said before, the shop owner felt it sounded a bit lazy and thought it needed a bit more timing.

They added 2 degrees more timing to bring it to 17 initial/47 all in (mechanical and vacuum). Torque seemed to climb, but had a weird peak (see green broken line on chart around 2900-3100 rpm), but hp dropped significantly. I will say though, that looking at the chart afterwards, it looks like he shut is down early (about 3700rpm) but I don't know why. Seems like that would explain the drop off in horsepower. My guess is he saw it was tracking under the previous run (marked in red) and didn't bother to finish the pull. He made a comment that "Well, we've seen diminishing returns" and set the timing back to where it was at 15 initial/45 all in and Hp climbed back up to where it was before with torque at 340 ft'lbs.

So,..... Asking for your opinions..... I don't have anything to compare to. I know everyone brags (and sometimes exaggerates) their power and dyno results. Just wondering how I should feel about 254 rear wheel hp and 340+ ft/lbs of torque in a light little car like this. It's fun to drive, but seems a little lower than it could be

Am I in the ballpark of what should be expected for a cruiser, or could I draw some easy power out of this somehow. What can I look at to see where I need to go. I know the 400 was notorious for low compression when stock. I have a clean set of 915 heads I could easily clean up and install to bump the compression a bit. I've heard they will add about 1pt to the compression over stock 906 heads (is that true?).

Should I pull off the heads and see where the top of the piston sits in the hole so we can see what the static CR is? How do I tell what the cam is? Can I put a dial indicator on the rocker and roll the motor over to try to see lift and duration (I have CAD software and could easily model up a degree wheel to measure degrees)?

What I know of my set-up:
1977 400 block
906 heads
Demon Speed Demon 750 carb (I believe)
Shumacher Tri-Y headers
A833 4spd (Dyno run in 3rd gear)
3:23 8 3/4 Suregrip