They weren't idling at 1300rpm. One was high that day because of a throttle cable issue. Once that was fixed I wanna say they were idling about 1000-1100 in neutral. And around 700-800 in gear . Actually, prob some of the nicest idling big blower motors I've seen, well carb wise.

These aren't truck motors with RV cams !!! Heck, mikes 1200hp 8 liter whippled carb motors idle at about 700 in gear. Mine sit at 1000 in nuetral and about 700-800 in gear also.

We'd be able to idle them down more if we were running some 23 mirage plus props . Would efi make them idle a little smoother, sure. im not sure i can swing the 8-10 grand to do the conversion so I won't have to give them a couple squirts in the morning....rootzefi has some nice kits for the roots blower setups. Not too bad at 6500 bucks a side ....:party-smiley-004:

Fountain Jeff has 900's with Bravos
Mike Tkach twin 950's with Bravos (cat)
My Cat had 900's with bravos
Dans boat would idle just fine with Bravos

All idled perfect, I dont mean to bud in my 2 cents because all I know how to do is spend money :)

You lucky SSM guys !!!

Thats it,,,,,Im shopping for a # 6 42 Tiger now LOL !!!

The jist of this whole discussion,,,,,, would I swap a good running carb motor to EFI,,,,probably not

Would I swap a EFI motor to carb,,,,,1000% nope !!!

believe it or not,im not getting in this pizzin match,but i will say the new fi setup,s like holley,s dominator are more tunable than a good carb,but the merc system on a 415 hp 502 is primitive at best,it has no o2 sensor,no barometric pressure sensor,and no capability to self tune.it is programed for the 415 engine and will run good in stock configuration,but must be reprogrammed if changes are made to the engine,and if you live in florida and want to take your boat to tahoe,its going to be fat because it was not programmed for the altitude.if it was carbed,all you would need to do is change some jets.i know smitty has this setup on his procharged engine,maybe he will chime in with what he had to do to make it work,and what it cost him.just think fella,s,a few more months and we can have this conversation out in the big lake over beers,or whatever it is you like to drink on a hot summer day.

100 % agree,,,,,Ill even take that a step further.

Merc sends them out to run anywhere in the world and on the worst fuel possible and be safe,,,,look at the first Gen 525 EFIs......soot the transom in seconds flat !!!

:evilb:And since you brought up cost to " make it work ",,,,,,now you know why I always leave my stuff the heck alone and just enjoy boating !!!!

Im to poor !!! LOL

I agree! And even worse, the stock 575SCI tune.

bob,i noticed you talking about your engine in a couple of threads,can you tell me about the parts list ?im interested to find out how to get that much power from a 540 that will idle low enough to put in front of a bravo drive.

540 dart block, 345dart pro 1 heads,comp solid roller cam, dart intake,1000holley carb, jesel rockers,elite comp lifters,msd box and dist.10qt oil pan.ss headers. i use a m1 a/f box to dail the motor in .

what is the cam part number,what pistons and can you post the dyno sheet.