My First Dyno...
 

oy vey... whatta day. Left work early, telling my boss I had an appointment to take the car into the shop... didn't tell him I was taking the Cobra in for dyno testing... (sssshhhhh!)

Man, it's more work than I thought it would be... I'm BEAT.

Got there at 2... was about 3 by the time we got the beast onto the dyno. We finally finished around 7 PM. He gave me instructions, as he informed me that I would be doing the driving (mistake number one). Must've done about a dozen runs, but only a couple were decent... the best one was with no load on the rollers. He had told me to be careful about missing shifts- and I kinda laughed. The laughter stopped once I had to do it! I bounced off the rev limiter once or twice. Felt like a total dufus after the first few runs.
Part of it may have been the synchros, but most likely the major part was my shifting techique (or lack thereof)... kept trying to shift too fast. I need more seat time. Was definitely a learning experience. It's not as easy as it looks. And of course, I was more than a little nervous as I'd never redlined it before (thankfully, I brought earplugs).

Previous dyno sheets didn't show the air/fuel mixture, so main objective was to get a good baseline reading & go from there. Was running WAY rich.

Ended up bumping up the timing about 3 degrees if memory serves... re-jetted the carb several times (4 I think) to put the fuel where the engine liked it- on the high end of the secondary I think... am still a little woozy from the fumes!

Even with my crappy driving skills.. the engine performance pretty much stayed the same after the timing & jet changes (~450 hp/tq @ wheels).

I can't say enough good about HotWeyer Performance in Canyon Country, CA!

Corey Weyer's been building race engines for 20 years. He put up with my inexperience and my boneheaded questions. He was patient from start to finish, took great care while working on/around my car, and is truly a class act. Quality work at a reasonable price. I recommend him highly to any who need dyno/tuning services. I'm not easily nor often impressed... this was a pleasant surprise!

Now if I can just get the smell of gas out of my nose!

Next up... fix my non-functioning brake lights. Then I can start addressing the vacuum issue (lack thereof) for the brakes. Am going to try a reservoir can first, but may end up going with a pump. We'll see...

Slick61, those are some great numbers. Your KC 427 should be making somewhere in the upper 590 range at the crank to make 450 rear wheels. They build fantastic motors!

Enjoy!

James

yea, it probably made a bit more originally (but not much), compared to now. When the engine was built, it dyno'd at around 612 hp @ 5900 rpm & 615 lb-ft of torque @ 5000 rpm.

I believe those numbers were attained when it was running a Da Vinci 950 cfm carb.

It is now running a Holley 770 street avenger, so it might've lost a little off of the top end. (I still have the Da Vinci)

The engine was what sold me on the car... such a work of art. Was nervous about the extreme rod angle of a 427 stroker, but knew that the Dart aluminum block was plenty stout, not to mention light. The car weighs in at 2240 lbs, so it's a screamer... both ballistically and aurally. The whole car just shakes with nervous anticipation when idling at stop lights. Was telling the guys at work about the "session" & several commented how they wished they could've been there to hear the engine at full song, up around redline. It was definitely an experience (glad I had earplugs!). With the dyno being in a single-car bay (of concrete walls), I'm sure everyone for several blocks got a taste of it. Could definitely tell the effects of re-jetting with successive runs... lots less smoke.

Slick, do you know your cam specs?

I'm also running the 770 Street Avenger. I was told by the engine builder/tuner that a Holley HP950 would up the horsepower by 35-45 hp in the top end. I love the streetability of the 770 though, wouldn't change it for anything.
Cheers,
Richard

Comp Cams roller cam

Lift: 0.576/0.576

Duration: 318/329 @ 0.006
252/262 @ 0.050

Lobe lift: 0.3600

Lobe Separation: 108.0

Solid or hydraulic roller? What heads are you running? Are they 205's or 225's?

hydraulic... 225s...

Slick61,
Do you have any oil leak problems?

... none so far... for now, the engine's bone-dry... no drips or leaks anywhere.

I bought a huge metal drip pan at NAPA a few weeks ago, so that I could monitor the situation. My only leakage so far has been the rear main seal, and I think most of that was from not being driven enough, as the pan has been completely dry since I shoved it underneath.