serial number is on the upper housing, left (driver) side on the sticker that says Mercruiser. It will say 1.65 and then the serial number on the bottom of that sticker. If the sticker came off, or has been replaced its gone. If the drive housing was ever replaced its gone.

No fastech 271's had a 1.5 from Formula.

Check your upper housing where the trim rams bolt up. Pull that pin, and you will see a plastic spacer BEHIND the pin. Switch that spacer to in FRONT of the pin. Now you can tuck your drive more, and it will get on plane a bit easier. but PLEASE be aware, if you get on plane, and do not trim the drive a bit, the boat will bow steer badly. Thats why Formula did the spacer this way (its in the way a B3 would be).

The 271 will never be speed racer to get on plane. But the above helps a bunch, along with having the tabs down.

Our 271 with 525 comes with 1,50 gears and it did 72 top speed-
another 271 with 500EFI does 70

The 1,65 on 271`s with black engines is an advantage since you can run a 28 ´prop which is one of the pitches with best performance

The 271 with 525 also uses a 28 ´prop , but with 1,50 gear ratio

the Bravo XR is not available in 1,65

As Formula built very few 271's with blue motors, I am not aware of what drive ratio they used. If you are getting 72 GPS from a 525 you have a really fast 271. I'm surprised that you are spinning a 28 with it, as that is what I used on a stock 415 and saw 5000 hitting the limiter

Zone5,
I have a Blue motor HP500, according to SN look up by another thread poster (lakematdude), it is a 1:50 ratio. So it is possible that this 271 came with 1:50. Thanks for all the good info about Formulas'.

As I stated, Blue motor 271's were few and far between. When I stated that no 271 came with a 1.5, I should have been more specific. My bad.

All is good, thank you for info. Always learning.

Zone 5

How many 271 with 525 did you drive by yourself ?

28 `lab finished Bravo 1 LH prop is standard on 271 with
496 HO and 525 EFI

The differenve is as stated before the gear ratio
at 5000 RPM with 1,65 the propshaft revs 3030 RPM

at 5000 RPM with 1,50 the propshaft revs 3333 RPM about 10 % more which results in about 10 % more speed at same RPM

The 525 HP rev limiter is at 5450 compared to 5150 on a 496 HO

Our 271 with 525 revs 5350 at 72 MPH

The 525 is usually 540 HP at the propshaft

comapared to 470 HP (500EFI) and 425 HP (496 HO)

Friend of a friend has/had a new 271 Fastec with a 525 EFI on a lake in North Carolina back in 2006 timeframe. Similar numbers to those above. He was really disappointed with its performance, considering it was brand new and had a 525 EFI in it. Tried a variety of props and it was still only a consistent 70 mph boat. He put it up for sale pretty quick and was having a tough time trying to sell it ... don't know where it ended up going.

Never drove a stock 525, as I stated, No one I know spent that kind of money on the boat. The upcharge from a black motor was some stupid high number.

I find your RPM's and speed with a 1.5 interesting. I spun my 28p with a 1.65 at 5400 and saw 71.5 with just shy of 600 HP. I though my slip numbers were bad. Yours are horrible.