I have finally gotten around to follow up on dyno testing of my EMC 303 Y Block, and found a couple of rookie mistakes that I don't understand, but it is what it is. My timing when I took the engine off the dyno here in TX was best at 37* total, and produced the same numbers at 38*, so we decided to leave it alone and dial it back in Ohio if needed. The horsepower was 453.7/390 tq and several pulls over 450 hp. We were down 24/24 on our dyno pulls at EMC, and nothing we did seemed to affect it more than a few horsepower. However, when I checked my timing here, it was set on 42*, and we never actually changed it during the dyno session (my mistake), or messed with it before starting the engine here this week. That cost me about 12 of those 24 hp we lost, and we were starting to think maybe the dyno was a bit happy here, but it has not been in the past. We bought two sections of 4" flexible exhaust tubing to add to my header extensions like they use at JE Pistons dyno cell, and lost another 10 hp, bringing the horsepower down to 430, which is what we made at EMC. So, tuning for the small flexible exhaust tubing, and timing set way too high were responsible for the loss of the horsepower difference from TX to Ohio. Took the exhaust tubing off, and set the timing correctly, checked valve lash, plugs, and made a couple of jet changes for the weather here, and we were back at 454 hp/389 tq. Tried a new intake manifold, and hit 461.2 hp/399.7 tq with the same carburetor we used at EMC. So the little Y now has 67 dyno pulls, makes over 461 hp, and nearly 400 tq. Not too shabby for a 62 year old iron head Ford. Joe-JDC