Thread:

20.5 Advantage Classic

Greg,

I have a Advantage 20.5 Classic closed bow and was wondering how much horsepower these hulls will handle. It currently has a 454bbc with a AT309 pump, hyd turbine trim and a aluminum AA impellor. It tops out now at 64 at 5000rpm. The boat is solid at this speed but would like to get more out of it. I would like to supercharge or turbo it, but leaning towards a blower as i already have a set of Lightning headers on it. The boat came from the factory with a skeg but it was broke off when i got the boat, should I replace the skeg and does it help the handling much?


Thanks,


Patch

I thought i'd put my two cents in, i have the same boat 454 bbc with an a/b impeller, and i'm turning 74 mph @5000 rpm with the help of lightning headers and some re-jetting. I bought a nitrous kit and called Advantage to see if the hull was good for it, they told me it was good for 90 mph easy. Decided against the nitrous though and sold the kit.

Originally Posted by Patch

Greg,

I have a Advantage 20.5 Classic closed bow and was wondering how much horsepower these hulls will handle. It currently has a 454bbc with a AT309 pump, hyd turbine trim and a aluminum AA impellor. It tops out now at 64 at 5000rpm. The boat is solid at this speed but would like to get more out of it. I would like to supercharge or turbo it, but leaning towards a blower as i already have a set of Lightning headers on it. The boat came from the factory with a skeg but it was broke off when i got the boat, should I replace the skeg and does it help the handling much?


Thanks,


Patch

Patch, The 20 Advantage is a good solid boat and like Advantage said it should handle 90 mph without any problem. To pull a double A 5000 rpm's and run 64 mph I feel is very good. To take the same boat and run 74 with a smaller impeller at the same rpm I find rather confusing. What 454 do you have? Do you have shoe rideplate, with a droop, loader grate or any other mods. Did you GPS this boat or r you going off the speedo.

Originally Posted by greg shoemaker

Patch, The 20 Advantage is a good solid boat and like Advantage said it should handle 90 mph without any problem. To pull a double A 5000 rpm's and run 64 mph I feel is very good. To take the same boat and run 74 with a smaller impeller at the same rpm I find rather confusing. What 454 do you have? Do you have shoe rideplate, with a droop, loader grate or any other mods. Did you GPS this boat or r you going off the speedo.

Greg,

I have 10.5-1 comp, Iskie cam (can't remember the specs custom grind) Torker 2 manifold, 850 double pump holley. It has a ride plate that is about a foot long, no droop or loader. Speed was on a GPS. Would a droop help on this hull? Also would replacing the skeg that is broken off in about the center of the boat help turning? The question about the A/B impeller was from another readers post.

Thanks,

Originally Posted by Patch

Greg,

I have 10.5-1 comp, Iskie cam (can't remember the specs custom grind) Torker 2 manifold, 850 double pump holley. It has a ride plate that is about a foot long, no droop or loader. Speed was on a GPS. Would a droop help on this hull? Also would replacing the skeg that is broken off in about the center of the boat help turning? The question about the A/B impeller was from another readers post.

Thanks,

Patch,
I don't like using this site to thread but here go's. I find it ironic that i seem to have the same motor with an isky cam that i've been told by the previous owner that it has a special grind. I have been searching for answers on this motor for years. Have you checked out your heads yet. There are sites that you can put in the numbers on the head and it will tell you what you got. Mine came up 1966 closed port heads off of a 427 bbc I am gonna call Advantage on Monday and see if they had a special indmar package motor they were putting in these boats. By the way it is a 1988 model. I have done nothing to this boat except maintenance.

Originally Posted by greg shoemaker

Patch, The 20 Advantage is a good solid boat and like Advantage said it should handle 90 mph without any problem. To pull a double A 5000 rpm's and run 64 mph I feel is very good. To take the same boat and run 74 with a smaller impeller at the same rpm I find rather confusing. What 454 do you have? Do you have shoe rideplate, with a droop, loader grate or any other mods. Did you GPS this boat or r you going off the speedo.

Patch,
I think we are the owners of an Indmar Jetpack Motor. I will know for sure on Monday, hopefully with motor specs from Indmar.