HP vs. MPH???? any link?? Quest for 70mph

[mile2885]

Ok, ok..... forgive me if this is a repeat topic but i'm just curious. WhatÂ’s the correlation with Hp and mph. My boat does 68mph on the gps with a stock 454 and tight pump (12-jg with place diverter, droop and shoe/rideplate)....at 5200pm...( I can get it up to 5500 but don't want to sink the boat when parts start to shoot through the bottom end) The engine has a edelbrock intake, bassets, holley 750, and a cute little cam. Guy at the machine shop said to go with a different cam along with large oval BBC heads (049s are on the way) and a airgap intake with a 1" spacer. Said it should be a "sizable" difference in hp. Anybody think that hp will get me to 70 or am I just wasting time, $$$ and gas?????????????

[djunkie]

Seems like a lot of work and money if you only want another 2mph.

[Jetmugg]

What exactly do you mean when you say you can get it to 5500 rpm? If you can run 68 mph at 5200, then 5500 will easily put you over 70.
If you can get to 5500, then put your foot in it, let it run 5500, and see what the mph is.
SteveM.

[Bryan Rose]

My boat does 68mph on the gps with a stock 454 and tight pump (12-jg with place diverter, droop and shoe/rideplate)....at 5200pm...( I can get it up to 5500 but don't want to sink the boat when parts start to shoot through the bottom end)
Not to be a smartass but that pump aint so tight..........5200-5500 REVs on a stock probably 330 horse BBC .................. unless you have a b or c cut impeller in there. Do some checking aroung in there.

[oldbuck40]

Ok, ok..... forgive me if this is a repeat topic but i'm just curious. WhatÂ’s the correlation with Hp and mph. My boat does 68mph on the gps with a stock 454 and tight pump (12-jg with place diverter, droop and shoe/rideplate)....at 5200pm...( I can get it up to 5500 but don't want to sink the boat when parts start to shoot through the bottom end) The engine has a edelbrock intake, bassets, holley 750, and a cute little cam. Guy at the machine shop said to go with a different cam along with large oval BBC heads (049s are on the way) and a airgap intake with a 1" spacer. Said it should be a "sizable" difference in hp. Anybody think that hp will get me to 70 or am I just wasting time, $$$ and gas?????????????if your not willing to increase the rpm then forget 70,but then again weight,the cut of your impeller,style of boat,altitude,,,,,,could go on forever! all these things has everything to do with it! like the guy said STAND ON IT! and see what you come up with!

[NOTALENT]

ditch the wife and kids...keep the beer and the dog...and u will hit 70 :hammerhea :D

[mile2885]

ya but that's only 300 rpm. With all the bouncin around ect it might have been to 55k. Just cheked the gps and the top speed was 67.8 that was just with me in the boat. The engine is already outa the boat due to bent rods :( so since I have it out and all apart.........I figure I might as well do it now. Pump was redone and has about 40 hours on it. Sorry if this was a dumb ass post. I just don't undersand how i would see any more mph with more hp if I'm already able to spin 55K. So I take it look into the impellor cut?

[oldbuck40]

ya but that's only 300 rpm. With all the bouncin around ect it might have been to 55k. Just cheked the gps and the top speed was 67.8 that was just with me in the boat. The engine is already outa the boat due to bent rods :( so since I have it out and all apart.........I figure I might as well do it now. Pump was redone and has about 40 hours on it. Sorry if this was a dumb ass post. I just don't undersand how i would see any more mph with more hp if I'm already able to spin 55K. So I take it look into the impellor cut?i can almost bet its not an (A) with a stock 454 turning that many rpm's,,but it sounds like you caught it just in time b/4 any serious damage was done to the block and the hull. ahh hell punch it out 30 or 40, cam,good springs,NEW RODS!!!, good intake and carb and you should be set! oh and by the way no such thing as a dumb ass post in here! hell if ya dont ask how the hell are ya ever going to find out! good luck with the rebuild.

[Bryan Rose]

Sorry if this was a dumb ass post. I just don't undersand how i would see any more mph with more hp if I'm already able to spin 55K. So I take it look into the impellor cut?
There are no dumbass posts here, I ask some of the stupidist ?'s around. We just get straight to the point around here.
Bryan

[FILUCKY]

5500 RPM on a mostlikely "A" impeller with a stock or slightly worked 454, you better get a second opinion on that rebuilt pump. You should only be around 4800-5000 RPM tops. Have you checked your intake grate for rocks or other crap that could be blocking your flow and letting your pump cavitate alittle? It can happen if you are still running the stock grate.(but it does save your impeller from the big crap)

[Squirtcha?]

ditch the wife and kids...keep the beer and the dog...and u will hit 70 :hammerhea :D
Ditch the dog too! :D

[LVjetboy]

Mile, if your cam and head upgrades net you 70-80 hp you'll see that extra 300 rpm. Don't know anything about your boat, but a typical 18-19' jet can see as much as 5 mph more top end with this added power.
jer

[jrork]

There are no dumbass posts here, I ask some of the stupidist ?'s around. We just get straight to the point around here.
Bryan
Bullsh*t, I am the proud owner of the dumbass posts around here. Go find your own...... :D

[kachina]

The more the impellar is cut the high the rpms will be, if the pump is not tight it will also rev out high, also have our rpm gauge checked. Im haveing my impellar cut to a AB or slightly more on the B side, that will put me at about 5000rpms on a slightly built 454. Also i found that my tach needed to be re set.
Good luck

[ANY&ALL]

I had the same set up. set back, ride plate, shoe, place diverter, stock 454, headers ,cam and 750, 5000 rpm 68 mph gps built new moter 10.2-1 comp. rec port heads pocket porting air gap intake 850 double pumper 2.19 in 1.88 ex and extreme marine 278 cam from comp cam with the same set up 81.7gps thats runnig a A impeller at 5500rpms and i added 400 pounds worth of interior and stereo i weighed it be for i installed it and a 4 degree wedge