Mugen
hope it was usefull to you.

Isuzuguy
well actually vegas can be decieving. The last time I was there for the speedline race last year the air density was really high. It was detonation central for us. If your going there I would actually plan to take a two piece pipe setup and step down a plug range or maybe 2 colder if detonation becomes a problem. I would strech the pipe a quarter inch longer than your one piece setup first. The other option is to use an RD one piece pipe and take both length headers we have. start with the short one and go to the long one if detonation rears its ugly head. I pushed three engines to the limit and killed 2 of them and that has not happend to me in a long long time, Broken pistons. Gearing the car to tall can cause detonation too, as can to lean a top end adjustment. I think I would stay at 21 especially on 40 running at sea level or close to, above 80.

How to identify detonation: the plug will be burnt in a way that the plug looks gray and bristly where the wire is left. If this happens take the head off and look for the piston and or head to have a Matte sand blasted look if so the engine is detonation and it will kill itself unless steps to correct the condition are taken immediatly.


Ziggy
I'll make it easy for you
3 choices for your engine
RD one piece 615L version
Nova 625 version
Novamega TPO6

then gear the car to get the torque where you want it. A torque pipe for the sake of torque which can be compensated for with gearing will hurt you. Once you have achieved max torque by gearing the car if you still feel you could give up top end then look for a torquier pipe.
That is the way I would go about it.
RD will be releasing a new pipe I designed very soon (next month) that should jack up torque and horspower beyond the 615 RD pipe. However I still like the 615 alot and consider it one of the best value/performance pipes for the money. Theres a pipe that starts with an O that makes a good paperweight.