Although the Bullitt
put down good power, the recently-rebuilt engine needed some sorting. The engine had been detonating at high rpms, since I first bought the car. Changing the tune didn't fix the detonation, so the engine problem was likely internal.
Fortunately,
Piedmont Custom Motorsports is just down the road from me. I hadn't had a chance to work with PCM previously, but I'm fortunate that they
know Mustangs of all years and were eager to help me.
PCM found that the power level was actually low—for the surprisingly high 19psi of boost. Reinstalling a stock larger blower pulley for a more reasonable 13psi resulted in a big drop in power. And a leak down test showed poor engine sealing. At this point, the motor came out to have a closer look.
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The heads showed previous detonation damage/repair around the spark plug holes. |
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A new threaded insert on one spark plug hole could be introducing a hot spot into the combustion chamber. |
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In addition, not all the valves were sealing properly. |
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PCM dropped the engine/crossmember/trans out from below. |
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PCM hooked me up with a set of stock replacement heads in great shape for only $300. The machine shop properly cut the oversize valves from the original heads and installed them. At this point, I figured the upgrade to Stage II cams was worthwhile... :) |
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While the Bullitt was in surgery, I figured I'd clean up the intake. I spent a few hours disassembling, cleaning, and painting... |
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And I ended up with this. The end-of-day lighting is harsh in this photo... |
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Here's the intake on top of the motor at PCM. They also installed a Centerforce clutch and adjustable quadrant for me. |
Here's a video of the dyno, showing 533hp at only 13psi.
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