The power is in the huge roller cam and the porting that is allowed in super stock class. With around 240 cfm flow on the intake side 470 HP is a walk in the park to get with that big honkin roller cam.(if they get that flow out of the heads? stock is right around 200 cfm on the intake so that much cfm can almost begotten with some chamber work) Thinnest rings per the rules as well will help which = less drag as well as bearing clearances in the sweet spot. Its not always about making more HP as it is about freeing up the HP that's already there. Windage control can free up quite a bit as well, as much as a 20 HP increase. Derek
Hey I never disagreed with that. The only thing I really disagreed with was the 10:1 vs the 9:1 thing. All the rest of it pretty much applies. If the cam lift is short enough, then by all means, deck that sucker to zero. That wasn't the point, but it all depends on the combination. Gary
Keeping things secret is what keeps them competitive. The whole point here is that they did it using stock piston design and an open combustion chamber. All the rest of this talk is just side-points. I think they have to keep them a certain distance below deck too, don't they? Or maybe that's the stock class and not the super stock. The spark begins to ignite the fuel/air before TDC, so where's the quench then? The piston spends very little time at TDC anyway. Think about it. There's a reason Buick 350s love lots of spark advance... Gary
Ding ding ding ding!! Blueprinting is where it's at. Even a bone stock engine can transform from ho-hum to daayum! Gary
OK, back on topic. See attached pics of a large chunk of casting flash I found in an intake port. The phillips screw driver shown behind it is a 1/4" shaft for comparison sake. Also see the intake gasket mis match to the head. The gasket was trimmed to fit the intake manifold port opening exactly. This is why you shouldn't buy a "gasket matched" intake used. Now I've got to cut all this out and will have a bulge in the intake track.
I saw Steve's port work on those heads yesterday. Real nice! He pays attention to detail, like his wheels!:TU:
Assembly almost complete. Compression ratio ended up at 9.35. Will run fine with 92 octane. Crower level 3 cam checked out spot on, installed straight up. Push rods were the perfect length and were re used. New stock oil pump will replace the hi volume junk that was installed at last rebuild. See my oil pump post from today. I am very impressed by the Autotech pistons. Very lightweight. They do use Chevy wrist pins so you need to have the rods small end opened up. Ring are low drag and very thin. Must also have entire rotating assembly balanced. Remember to get all required parts when upgrading to dual valve springs. You will need to have the step machined of at the base of the valve guide boss and need to add a locator cup. Viton seals from TA Performance fit nice inside. New retainers for the dual spring also.
My 73 stock 350 pistons have a compression height of 1.835 with a 24cc dish. They were in the hole .066. I measured the compression height with my cnc mill and an indicator in the spindle. Mike
Cam break in done with inner spring installed. These springs are not that strong, would not gain anything by removing them. Only 92lbs closed and 240 open. Have a little tuning to do this week end on the distributor and carb.
No Lapeer. Just have to limit the 40 degrees mechanical advance down to about 15/18 and reduce the accelerator pump shot some. The 200r4 needs a check up so the driving is limited for now. you should see it at Norwalk Saturday.
