199025sxtWarlock

I have a 25 sxt Cat. going up from 425 hp ( estimated) to a Dyno proven 550 horsepower..468 ci. I have it were it falls off @ 7000 rpm only to 532 hp.
will this drive handle 6500 - 6700 rpm in spurts up to 2 minutes or so ?

I went with a small cube and higher rpm range with this motor .
( had this motor in my 24 Euro and it pushed it to 95.1 in a 2.5 foot chop.. I am a very experineced driver with the 24.. its a chining bi#ch over 88)

its a motor I had on a shelf for years and just freshened it up for next season.

any bad news or will it be ok. ?..And as always I never punch nothing from off plane..I know thats a killer.

THANK YOU !!

Griff

Heat and torque are what kill Bravos. You don't have extreme torque, but spiinning that fast will create the heat. Short bursts should be alright though.
BTW, the upper is the weak part of Bravo drives.

Mr Gadgets

I was told years ago that there was a limit on rpm for the B1. The pinion gear trys to walk over the driven gear. But experience shows me that if the lash is setup correctly then there is a better chance of it surviving. Make sure you have a good drive shower to deal with the heat.. And check the fluid often for signs of heat.

199025sxtWarlock

thank you for the advice.. should I put one of those billet tops on also ?

rhinoLX

If you still have one of the original thin top caps, absolutely replace it. They allow the housing to flex to the point where the vent screw could sometimes come loose, not to mention flexing is a bad thing anyway for obvious reasons. The thick, ribbed, late style Mercury cap works fine. For single application order BIII XR top cap, comes without the tie bar mount on back. Of course if you're looking to add a drive shower I'd choose one of the aftermarket units with internal plumbing for cooling. New cap and cooling all in one.

P.S. A good synthetic oil is a must.

Mr Gadgets

If you do go to a different top cap, make sure to mearsure the depth of the surface of where the race shim sits. It can be different and that effects the setup of the gear stack and lash adjustments. Also use studs to hold the cap on, that will also help stiffen the upper case.
If you run in salt water, I have been told some of the top caps can plug up if the cooling holes are too small.

Waveform

iTrader: (1)

I would start saving up for a beefed up Bravo. I would rather have a one-ton axle in a half-ton truck, than have to worry every time I put the throttle down. That being said, I would still do the cheap upgrades for now, ittl at least give you more time to get the coin together. I'm also afraid that you're going to have to spin that motor pretty high, even at cruise. So if you figure cruising around at 5000+ rpms, thats about equal to stock WOT on a 454 Mag/b1 combo.