1989 311 motor options
 

I need some help with motor options, I have a 1989 311 with 502's which I blew one up. having both rebuilt but not sure which way to go since I have trs drives what hp can these handle.And has anybody built up a 311 if so what motor package and speeds? any info would be helpfull..thanks

Mine did 70 with 502 MPI engines and Bravos and over 72 with HP500s and Bravos but I haven't got the right props on it yet. The TRS should be able to handle 500 HP pretty easily but you won't get as much speed since the gear housing is not as hydrodynamic and you lose some power through the transmission.

Are they carb 502's? A nice cam, a little headwork, some other goodies, and 550-575HP is not hard to do. If you have the motors out, now would be the time to refresh the trannies, and have them add a extra plate...The trannies can take alot if built properly.....the TRS drives, can take 600HP a side in a 31ft boat. Just dont abuse them. Easy on holeshots and don't get carried away launching off waves...


Where you located? Lots of good MARINE engine builders around...be careful with car guys rebuilding your motors....Depending on where you are, we can recommend one..

yes they are carb motors I was getting 73mph on gps motors were pretty much stock besides good exhaust and msd ignition. Trannies were already beefed up because there were blower motors in the boat before.I was thinking about je ultalight pistons comp cams and roller rockers and lifters port and polish heads and a hardin marine intakes, all new gauges .well pretty much redo the whole boat!!!!!!!!!just like the looks and the ride of formula boats. will be posting picks of the build..Im hoping to get around 550 to 600 hp

forgot to add Im in virgina just south of Richmond Thats for the replies

Cool..if you wanna send your heads out, have Jim valako in grand rapids Michigan go thru your heads. He is very reasonable, and flat out awesome with heads. He knows what areas to work on, to get results, rather than just a general port job.....he also is now casting his own marine heads...

does he have a web site?

My HP 500's are at Jim V's shop right now. They are now 509's,with new comp roller cam, new comp roller rockers, Jims port work on the heads, and some other little tricks. Also running 9.5cr, they should be making 600 a piece.

Ive been working on mine getting everything rewired painting the bilge, drive and all motor brackets lots of time and work!! waiting on machine shop now.(been there since january) but o well. I would be real happy with 600hp.

Ted something does not seem correct, I get just at 70 GPS as does my buddies (69mph) with 420's and TRS drives.

Well the 502 MPI is only 415 at the drive and it did 72 when I first got it. But after adding drive showers and the advent of ethanol fuel (both the same summer) I lost a couple. And I have not gotten the props right with the 500s. Although it does seem like you have to throw a huge amount of power at them to get anything close to 80.

boat would hit 73 on gps with me and half tank of fuel.looking to get 76 to 78 we will see

thank you!!

That sounds as an impressive speed to me with this setup, very nice.
Until the end of last year I have been running my 1989 311 SR1 with stock 454MAG's (365HP each) and bravo drives, stock mirage plus 23p and I was seeing 65MPH on GPS.
It surprises me that 2 x 415HP with TRS will give you 8mph more.
I have repowered with HP500's and I ordered a set of bravo 1 26P props at BBlades. Let's see where these will get me next month. With respect to the EFI, it is comparable with Ted's 311.

What is weird about these boats is the wide range of weight. My boat sits MUCH higher in the water then my buddies. His exhaust tips are just above the water. Mine are a good 4 or 5 inches over the water as I recall.

Paul I think what Ted stated earlier is that the 420's are rated at the prop not the crank like the 365hp motors are. So it is probably a 6-7% additional advantage.

Well, the difference in a full or emty tank is already close to 3 inches if I am right. I didn't know that there was so much variation in weight although I can imagine that various types of engines will differ something in weight and maybe TRS or Bravo will differ as well. Exhaust tips of my boat are also about 4-5 inches above the water with a half tank of gas.

So, are all 420's specified at the propshaft?

I always thought the older engines, like the 454/420, 454/365, etc, were rated at the crank. I think that is why the 454/365 got relabed the 350HP engine in the mid 90's.

I agree that is a great number for TRS. i think it is gonna take at least 600 hp a side to get a TRS boat to run 80.

didn't OFFTHEFRONTS boat run like 78 with 496's and bravos?

Yes, Offthefront had 600hp a side and his boat did about 78.
His engines were custom build if I recall well..

That boat has seen 81 since moving to SC

My 311 has custom 496 strokers 525hp with 6 disk trannies trs drives with nose cones, labbed 25 mirages thing is a rocket ship. check it out PHOTOS keyword TRAMP

:eek: wow with the ST box on or off?

Its still on. Im working on 85 now,some carb and prop tweaks do wonders. The cold air helps right now as well:drink:

Conrats man!!!!! That is one of the fastest 311's right now!!

Mike (offthefront) did one hell of a job on the boat. Just my turn to fix some things and tweak some things. Just a new page in its life.