Finally got the last iteration of Gary's Tunnel Port motor finished and dyno'd. It was a 600 hp engine before, with the heads used as Gary sent them. They flowed decent, around 340, but didn't have any velocity and petered out at around .600" lift.
We decided for the sake of data that we would try something a little different, so I sent the heads and intake to Lawes Mayfield to have them ported. He raised the floors in both the intake and head and increased the flow by another 40 cfm....380 cfm TP heads, with a smaller CSA than the factory designed them to be.
I changed the camshaft around a little too. Kept the same .050" duration, but added a lot of lift, about .150" more than before. Widened the LSA by 2 degrees as well.
I hated that we changed so many variables at once, but I know Gary didn't want this to be a dyno queen all its life. In addition to the head/intake/cam work, we also added some RaceTec domed pistons, which bumped the compression ratio up from 10:1 to 12:1, and rebalanced the crank.
The engine responded much, much better than I ever expected. On the very first pull to 5200, it made the 600 hp that the last iteration made at full song. Further tuning and pulling to 7000 saw a peak hp of 696 @ 6700. Torque was 589 lb-ft.
