Back from the Builder
For many years my dream was to have a really solid LSx based motor. I really wanted to take advantage of the improvements in the LSx design, including the 6 bolt heads. We’ve been nursing the ETP 245 cc Cathedral Port heads for nearly 6 years now. These heads flow as well as any of the 4 Bolt L92/LS3 Heads I have seen off the shelf so it was pretty much the heads themselves that enabled us to afford to go to the LSx. Our original intention was to bore the bare block to a 4.012 with the 4 inch stroke crank and come up to 427 Ci. We reused the Eagle rods from the LQ9 and since the crank was wasted, we had to go to a Callies Compstar Crank which still limits me to 1500 horsepower at the flywheel. We initially purchased Manley -3 cc dished pistons that would have given us around a 10.5:1 compression ratio which we thought would be boost friendly. The jig slipped when the machine shop was boring the LSx block. We had to go to a 434 cubic inch motor with a 4.0155 bore. The machine shop bought the new pistons which are Wiesco flattops. We had opted for the 427 Cubic inch build because that was the recommended best limit for the cathedral port heads. Not really sure how the bigger bore is going to sit with these current heads but we are moving forward to see what we have. The whol;e episode does put a new set of Mast Black Label Heads in my to do list. Similarly, we were worried about the turbos being too small with the 402 Cubic Inch LQ9. We were concerned about the 427 Cubic Inch build but figured that newer larger turbos were on the todo list as well. We figured we would go ahead with the PTE 6266’s and just have Reed Partridge at Works Turbochargers rebuild them. The thought is to go ahead and build what we have and not turn it up to maximum horsepower but move forward with a plan to beef up what we have as we go along. At any rate we are excited about the 434. We got 1145/1269 to the wheels with the LQ9. That should have been around 1200-1300 bhp. If we pick up another 100-150 wheel horsepower with the new build we should be within the maximum safe tolerances and perhaps get the car out and race some while we recover to begin to move towards the plan to replace out the Heads and Turbos. Down the Road I would like to go to a Callies Magnum Crankshaft or something equivalent and a better set of connecting rods.
New LSx shortblock back from the builder
Rotating assembly installed. Note the one piece reluctor wheel.
View from the top with the Cam Gear laying loose in the valley
Better look at the flattops
ETP 245 cc heads refreshed by the builder
ETP 245 cc Heads