353 Formula guys - need info
 

Looking for some info about what kind of speeds and RPM you're getting with what props at WOT.

I've got 502s with 28P Merc Bravo and she's running in the 4,700-4,800 range and not making it to 70 MPH on the GPS, does that sound right.

Thanks for the help and info.

Is it even on plane at this speed...Just Kidding. Seems a little off, the 496 boats are 72 to 74, I would assume the 502 would be very close, but I have no real knowledge on this hull/power. Maybe dropping down to a 26 to get the rpm up to get the last push will get you across the 70 mark. Are your props the labbed finished version or standard. Do they have a real shinny finish or somewhat brushed finish?

They're standard props (not labbed), good shape, brushed finished, not shiniy, but keep in mind they've been in salt the last several months,it's on a lift down here, but it's going back to LOTO here real soon, I was wondering what the max RPM should be.

I would be looking for 51 to 5200.

I don't know if the boat should hit 70 or not. I assume you recently bought the boat or you wouldn't be asking this question....so I have a thought:

My old 382 was fastest with 30P Bravos and would spin 5,600-5,700 (custom built motors). However, I wanted better cruise speed so I ran 32P Bravos for a 3-5 mph faster cruise speed. Those props would only spin about 5,200-5,300 WOT and the boat was 3-4 mph slower. It's possible the previous owner made the same decision I did and went with 28's vs 26's????

No, actually have owned the boat for over ten years, I've never been dissatisfied with the way she's run (top speed) or handled, I've never been a big speed demon, it's been a perfect boat, I've just never tried any other props on her and wondered what the top RPM should be on the 502s

I have a 2000 353 with 454 hp500 cam and heads last year. Basically 502, I ran 28 pitch props and got 75mph at 4800-4900 on gps on the best day. I have the same engines with b&m 250 blowers 5lbs of boost 608hp. I just hit 83mph at 5100 with a little bit more to go. Same 28 pitch props as last year. The cooler weather coming will help you out also.

if it responds anything like my 496 HO's, swap the 28's (too big IMHO) for a pair of stock 26 Bravos and loose nothing, but gain lower min. planing speed, midrange acceleration, and bring the RPM up and most likely break 70 with your 502's.

!00% proven win/win in my application.

This is your first choice Jim. My single 502 (509) spins a stock 24 Bravo solid at 65. Two 502's should get you past 70. If I lose the drive shower I'm normally 68 - 69. Although I did buy a 26 to try, just too damn lazy to change it out!!

Hmm..would like to know what would happend if I would put 26" to my 271 with 496 mag ho?