what Impeller would be best for the Olds ?

[kcsteck]

Im curious what Impeller would be best for the Olds 455. Mine 76 Tahiti 18ft has Berkely JC has agressor AB in it spins 4900 rpm and only goes 58 GPS Im lookin to get my RPMs down so I dont have to spin so high for the OLDS but still get some good speed.Use more of the torque. What ya think? B?
Casey

[malcolm]

Agressors run a little big don't they? I'd think an A or A2 to get the R's down.

[kcsteck]

Hi Malcolm,
I dont know if its to big or not. Dont know much about the pumps or impellers. I just pulled it out to check it today since motor is gettin rebuilt. Took it out and apart and has Agressor AB in it. looks brand new. Buts grindin on somethin on a part of it when I rotate it. Im gonna take it in to Jetboat performabnce have Tom look at it.im just lookin for anyones input.

[SmokinLowriderSS]

4900 against an aggressor AB cut.
An aggressor A cut should spin you arround 4750
I wouldn't go all the way to an aggressor AA but it should spin arround 4450 roughly unless the loss in HP drops it farther like 4400.
a Non-aggressor AA should equate pretty closely to an aggressor A.
You'll loose some speed with each size, maybe a mph or 2.

[kcsteck]

what would happen if i went to B more RPM?

[malcolm]

Yup!

[kcsteck]

K thanks malcom..def dont want a B then! id like a A or AA I think.
thanks for your insight.
Casey

[speedymopars]

I have an A on my 455, running a .490 lift 230 duration cam with an 850 DP, performer etc, pulling 5200 RPM (berkley chart 450HP). It seems well matched. Pump is a Berk 12JC in a 21 foot cheyenne.
I'll be GPS'ing it soon, it feels like 65 ish, but you never know those things until you have the real number.

[kcsteck]

sounds pretty close to what Im runnin. Im runnin 520/523 lift 230/236 duration Comp cams cam,750 Speed Demon on Victor intake. can pull 5k RPM about .400hp per chart for a A not sure what it was now knowing I know now that I have AB impeler. But that was with cracked heads and spun rod bearings that I never knew I had. GPS 58 before she broke. now Im rebuildin the mill. Cant wait to see what it does now with New C Heads all new rings and bearings. And im gonna get the pump tightned up and possiblly change the impeller. If I could get to 70 Id be real Happy! wish me luck.LOL
Casey