+1 on the 272 mine was Bone stock 502 efi 1994, Ran 70 + ALOT Seemed to like 2-3' water. Gps # Rich

rich it is hard for me to beleave you show a video please. my buddy has the same boat with a 502efi with 600hp running a 26bravo prop at 5100doing 69.9mph on gps. there is no way a stock motor doing 70+

I second that. At what rpms does he spin what prop through what drive ratio to run 70 with a 502 in the 272?I would think he should run faster with that power though. 70 is not much with 600 hp, the 278 runs about 78-80 with that power. Has he ever tried other props?

Everyone keep this in mind when it comes to hp numbers also: When you compare "factory" hp numbers boats will usually go a little faster because of the difference in dyno correction factors. To clarify there are (2) correction factors typically used-Sae J607 and Sae J1349
Most small, aftermarket engine builders use j 607 which corrects to 60 degrees and 29.92 baro, J1349 corrects to 77 degrees and 29.235 Baro.
J607 is more generous and produces bigger numbers ovearll, typically 4-5%. Example: merc builds a 525 efi and it dynos at 535hp, If a small independent shop were to dyno it the numbers would be more like 562 even though nothing was changed. So a guy could have a "600" hp aftermarket built motor but his boat will only run as fast as a Merc motor that made 570hp. The comparison could change even more depending what exhaust was used when dynoing, Merc always dyno's with the same exact exhaust as the boat uses, water cooled manifolds or headers, dry headersb are often used at independent engine dyno's, this could inflate hp another 20 or 30. So the 600 hp motor someone has might be comparable to 540 Merc hp. Now keep in mind too though, these Merc motors aren't magical either. I have seen alot of 25-28 foot non stepped v-hulls with various Merc engines including, 525sc's, hp 500's and 525efi's, most will barely break 70 mph unless it is a hull that typically goes pretty fast. I have met and talked to ALOT of guys with 25's and 272's, seen a few that would run hi 70's with blower motors but for the most part I have yet to ever meet someone with a bone stock 25 or 272 that would break 70 mph with any stock 496 or 502. I am not saying it isn't possible but I have paced ALOT of them, My 272 runs 100 mph, so I can usually pace any factory boat, been told by alot of these guys that they can run 70, 72 mph with stock power BUT when I pace them its usually at 63-66 mph, I guess I just haven't ran into the fast ones yet. My motor with the blower belt off made 657 hp on Crocketts Dyno , just like everyone else he uses the generous correction factor, I also did't have accessories on my engine so realistically it is probably equal to 600 Merc hp. My 272 has ran a best of 76 with Blower belt off, no fuel, tail wind, chop, perfect air, no passengers etc. It will run about 72-74 most of the time wit this set-up in more average conditions (540 cu inches), Smitty

Damn I can drive pretty good one handed!!!!!

Very good point. Had not really thought about it. I kinda think 600 true hp (SAE J1349) by default. Never understood why the independent builders don't go by that correction. The only one I know of who uses it, it Dustin Whipple. If I was to have an engine build by say YPM and purchased a say a 750 hp motor, I would expect it to compare to a Merc or Ilmor 750, and tell the builder that it has to make 750 hp SAE J1349. Nothing against YPM, just an example, and I'm sure Eddie would do it.

I agree your #'s seem slow for HP, but every dyno is easily manipulated. I have no video of mine running 70 on gps, but next owner found the exact statement to be true. It ran exactly as described and he bought it sight unseen and shipped it to CA, He's still running it.

What I find funny is just because someones buddies boat won't run speeds someone claims it's suddenly impossible. I'm running 84 on gps in a 302 with full Galley Package and Boss Package, but I've took the time to setup the boat.

My information I've posted wasn't to start a "which oil is better" thread, but to help the person in they're decision on which motor to go with. Proof is in the setup.

I would think he should run faster with that power though. 70 is not much with 600 hp, the 278 runs about 78-80 with that power. Has he ever tried other props? yes he try all kinds .so far thats the best smitty nice post . i have a smaller boat 24baja stock 365hp then made a 420 and 500hp now i change to a 540dart with 600hp now i got 718 hp dyno. like you a change setup and props.it take a lot to go fast!!500hp i was just hitting 70mphon a good day. so it is really hard for me to hear story about guys going 70+with 425hp hear my boat doing 80mph still trying props my best is 81.9 !! there is a lot of 25baja on the river and 65mph is the fastest i see them go which is pretty good for that size boat http://www.youtube.com/watch?v=2Kojm...eature=related

that fine helping some one but they need to no what motor really make that boat go the speed they went it to go!!!!! this guy want to go 70+in a 25 he need a lot of upgrades he not doing it with a stock 496. and we are not talking about a 302baja

I'm just giving you #'s on my current setup because I was quoted saying my 272 502 Mag wouldn't do 70gps. Not looking for a arguement nor to pass judgement guess in future I'll keep my real world experiences to myself.