Throw a leakdown gauge on it, or even just air to the cylinders with all the plugs out, you'll hear it coming out of another plug, the carb, or the tailpipe if something is leaking down
---------------------------------
- 70 Fastback Mustang, 489 cid FE, TKO-600 5 speed, 3.70 9 inch
- 71 F100 shortbed 4x4, 397 cid FE, headers, Street Dominator, 280H, 5 lug Dana 60, 4 speed
