lightnin
27 Jun 2008, 8:37pm
I'm in the midst of putting my 455 pontiac together. I've had some setbacks, but it's coming together finally.
I purchased some heads from KRE and had them CNC ported. The flow sheets show 311 CFM at .7 inch valve lift @ 28" water. I think the Exhaust showed 246, same lift and pressure. That's not bad for a Pontiac... plus they are aluminum.
These heads run an 85cc combustion chamber. I bought some TRW (Speed-pro) standard flattops from Summit... but two problems...
1) With my deck height and head gasket, this would yield around 10.2:1 CR with standard pontiac flattops. After talking to some folks much more educated than myself, I actually am going to go for a little less so I could have some wiggle room in the future with regards to octane rating or maybe adding forced induction.
2) the weight variance between the pistons I bought made it impossible to balance the rotating assembly. that's no good...
so I had a set of Ross pistons made.
Slightly lower CR, and also a much lighter piston and wrist pin. The TRW forged piston/pin for a +060 455 weighs in the realm of 790-820 grams. The Ross piston/pin weigh in the realm of 580-581 grams. That's a big difference.
I haven't actually received the pistons from the manufacturer yet, but I've been told probably early next week. No big deal. Once I get them, I still have to have the rotating assembly balanced.
In the meantime I prepped the block, mocked up the top end and port-matched the intake manifold. I've also spent a whole lot of time cleaning parts and working on the car itself. And busting ass at work too...
anyways, a few pics from my camera phone.
I purchased some heads from KRE and had them CNC ported. The flow sheets show 311 CFM at .7 inch valve lift @ 28" water. I think the Exhaust showed 246, same lift and pressure. That's not bad for a Pontiac... plus they are aluminum.
These heads run an 85cc combustion chamber. I bought some TRW (Speed-pro) standard flattops from Summit... but two problems...
1) With my deck height and head gasket, this would yield around 10.2:1 CR with standard pontiac flattops. After talking to some folks much more educated than myself, I actually am going to go for a little less so I could have some wiggle room in the future with regards to octane rating or maybe adding forced induction.
2) the weight variance between the pistons I bought made it impossible to balance the rotating assembly. that's no good...
so I had a set of Ross pistons made.
Slightly lower CR, and also a much lighter piston and wrist pin. The TRW forged piston/pin for a +060 455 weighs in the realm of 790-820 grams. The Ross piston/pin weigh in the realm of 580-581 grams. That's a big difference.
I haven't actually received the pistons from the manufacturer yet, but I've been told probably early next week. No big deal. Once I get them, I still have to have the rotating assembly balanced.
In the meantime I prepped the block, mocked up the top end and port-matched the intake manifold. I've also spent a whole lot of time cleaning parts and working on the car itself. And busting ass at work too...
anyways, a few pics from my camera phone.