The new, taller slugs put DM's pistons right at "zero" deck, which is what we like to see for the best possible power. In addition, they also raised DM's compression by a little more than a half point. Other than the new slugs, DM was put back together just like it was the first time. The file-fit Speed-Pro rings were gapped a little wider than standard to accept some extra abuse and a pair of steel O-ring Fel-Pro heads gaskets (PN 1003) were clamped on top.
For its next bash on the dyno, we will retest the Holley Street Avenger TBI fuel injection system that we had tried before. To make DM more TBI friendly, Speed-O installed a smaller Lunati hydraulic cam and some World Products Sportsman II iron heads. Then they topped it off with a Holley Street Avenger dual plane intake manifold to give the TBI the strongest signal possible. We asked Speed-O to reuse the COMP Cams 1.5:1 magnum roller rockers button up the ignition with a new computer-controlled electronic distributor from Holley.
We figured even though this equipment might not break any records in the horsepower deparment, it would definitely complement the low-speed torque characteristics of the street-worthy TBI. Who knows, we might break a new low-end torque record with this set up. You'll just have to wait until next month to find out. Because that's when we'll head back to Vrbancic's dyno once again to see if we can make the TBI fly.
Danger Mouse Rebuild Specifics For Part 16Compression: 9.1:1World Products: Motown block 4.030 boreWorld Products: Sportsman II iron heads 64ccLunati: hydraulic flat-tappet cam PN50179LUN (268-279 degrees advertised duration, 215-224 degrees duration at .050, .489/.489 lift, 112-degree lobe separation, 108-degree intake centerline)Lunati: crank, rods, and flattop pistonsHolley: dual-plane manifold PN300-36 Speed-Pro: rings and bearingsFel-Pro: gasketsMilodon: oil system and fastenersSpeed-O-Motive: assembly