My WOT RPM low?

[SWLAmarshrunner]

What RPM should I be seeing with a 61x single carb? Mods: riva red exhaust, f/a, 160psi comp, freshly rebuilt carb & tdr waterbox. Impeller pitch is unknown but I would like to know what a setup like this SHOULD be turning so I can make adjustments accordingly. Currently turning 6480rpm at wot & I weigh 190. Seems a little low to me. Running in the sport spec closed course class with this Blaster. I do have an ADA girdled head on the way to bump up compression to 185 but it still seems like I should be turning more than 6480.... unless the impeller is too big as it is and my weight doesn't help I'm sure.

I was at that RPM going straight and sitting on rear of seat. In a slight turn to the right, I noticed RPM climb to 6800 but would drop back down right below 6500 when going straight.

 

[Vumad]

My superjet is stock motor and carbs with head, B-pipe and 12/17 concord. 7200 WOT at 49mph gps. Not a blaster and slightly different motor.

 

[SWLAmarshrunner]

I'm going to have to figure out what impeller is on there right now. When my girdled head comes in, I plan on switching my B-pipe from my other blaster to this blaster. I just thought I should be getting more rpm out of it right now.

 

[Quinc]

Coffman pipe blasters are similar and make there max power around 6800. You can dry out the pipe and maybe gain a little more.

 

[billglass]

I've been trying to figure mine out as well same pipe. Mine averages 6540. I tried drying the pipe out and lost the low torque . I still also have to tune the HSS. (but having other issues since I forgot to put gas cap on and rode it) Sola I impeller. I don't think the riva red pipe is designed for high rpm. but could be prop.