Payback's new ZL-1

[Vegas69]

I woke up at 5:45 AM and was on the road around 7 AM headed for Pettis Performance to break in and dialin my new ZL-1 489. It just happens to be my birthday and I can't imagine a better way to spend a birthday. I showed up at Pettis around 10 AM. They were just finishing up all the plumbing to make her sing. It was exciting to walk in and see it all come together. He fired up the engine for the break and shut it down shortly after startup due to high EGT's. He tweaked the idle circuit and got them reasonalbe for the break in. We made a couple short pulls and Jason pulled the drain plug and checked the filter for debris. We then lashed the valves. After the first couple pulls I knew it was time to start tweaking on the tune. Jason Pettis is the definition of a Pro. We studied the efficiency of the engine and started playing with timing. We increased the timing and it lost power. We pulled 5 jet sizes out of the primary and secondaries and it woke up. As engines become more efficient they require smaller jets. We ended up with 666 hp at 6200 and 641 ftlbs at 4700. I feel it's absolutely the perfect engine for our circle jerk. Killer torque curve and it pulls to 6800 like it's pissed off. We did it on the next run. My goal was to make just as much torque as the old engine at its peak but make more HP. Not only did Jason manage that but he made the old motors peak torque 300 rpm sooner but kicked it's butt by 20 lbft at 3800 and a full 53lbt peak. He smoked the peak HP by 73hp with a very level power band above 6k. So basically I have more low end torque for autocross but way more RPM and Power to play with. The oil pressure climbed the higher we pulled her and peaked at 76 with 183 degrees of oil temp. We tried cooling the motor off and making more power. It made the same power 30 degrees cooler all at 34 degrees timing How can you argue with that. I can't wait to give it hell. I still love big blocks man!



Crank it up!