As I get further into the restoration of my Formula 255 Liberator I get closer to making some serious decisions about drives ratios and prop selection.

For those that are not familiar with this hull, it is a 24 deg. dead rise Deep Vee of the original 233 hull design...just streched to 25'-6". The Liberator is one of the earlier "Long Deck" performance versions similar to the 233 Interceptor. Liberators weigh 5622 lbs dry and draw 36". This boat has a freeboard that is about 18" ~20" higher than most boats it's length. With twin Mercruiser 260's it has about a ton on it's "ass end" but sits relatively level in the water.

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Conventional wisdom from the past has this boat with 19" pitch aluminum props (both turning RH) or optional 19" Stainless RH or 19" or 21" Stainless Cleavers. This is with standard Mercruiser No. 1 drives with 1.5;1 gearing.

Fast forward 30 years...we have new choices. Given the 260 Horsepower 350 Chevy's we look at the same old choices (except I reject the cleavers right away) with the addition of Mirage Plus 3-Blade or other choices in a 4 blade Stainless.

I have narrowed my options down to these:

1. 19" Mirage Plus with 1.5 Gearing...RH/RH rotation
2 21 Mirage Plus with 1.5 Gearing...RH/RH rotation
3. 23" Mirage Plus with 1.67 Gearing RH/RH rotation
4. 19" 4 Blade with 1.5 Gearing RH/RH rotation
5. Any combination of 1~4 with LH/RH rotation.

One idea presented on BAM Marines Knowledge Base website makes an argument for using gearing to make your reductions and run as much prop pitch as you can to gain a higher level of performance. I have no experience with this and welcome comment.

if I change to SEI 116 drives I have multiple choices with gearing and by ordering a different lower unit I can easily opt for LH rotation for the port drive. I know from experience (40' Sea Ray Express Cruiser) that LH/RH is a must with inboard set ups. I see it with big offshore out boards but see both configurations on stern drives. Is LH rotation on the port side an advantage for me in this boat?

Given the several choices I have listed and based on what we know about the boat...I ask your opinions on which choice is ideal based on all of you guy's experience.

I use the boat primarily for coastal cruising here in SE Florida with an occasional run to the Bahamas with others I boat with.
I would like to be able to cruise at 50 over long periods of time (poker run)....while having the ability to get up on a plane with out a lot of drama.

I would lean towards option #3 except w/ Rev 4 21's.

Better torque multiplier w/ the lower gears & better cruise w/ Rev 4’s

i am running 23pitch three blade cleavers on mine. they ain't bad. will really open it up this weekend. will let ya know.

Good choice...I appreciate your answer.

Question: No advantage in LH/RH vs RH/RH ? just curious

I ran a set of 21" cleavers on mine untill some A Hole stole them. Low end and staying on plane was terrible...top end pushed 70 GPS...I need a Tie Bar!!

Best over all so far was 19" Mirage Plus...jumped out of the water fast and mid rage was "snappy" up to about 60...but like the other 3: blades i have run...when I get to about 3000 RPM it falls off plane.

I like the idea of the Revilution 4. Saw an old F-26 running 383's and 21" Rev 4's lumbering along on plane at 3000 RPM.
I talked to the owner...he loves 'em and reminded me that an F-26 weighs 9000 lbs!!!

I might take one for the team and buy a set of Rev 4's. Any ideas on where a pair can be had for less than a 'thou?

I don’t have any experience w/ twins so I really couldn’t help you there. I guess both your engines are standard rotation? Do you get a lot of counter steer now? You should be able to reverse the shift linkage & run R/H & L/H props.

Another somewhat cheap upgrade would be replacing your heads w/ a set of Vortecs. I replaced the heads on an old 260hp w/ a set of Vortecs & a Performer intake & no other changes. It made a noticeable improvement.

If you play your cards right you should be able to get a set of RH/LH Rev 4’s off Ebay for 500.00

To go LH I have to change the lower unit on the port side...changes the gear. If I reverse the linkage I am still using the reverse gear set witch is not as "robust" as the forward gear.

Both engines are standard rotation

Anyway...I have heard that idea Re: the Vortec Heads and intakes...I wonder if the exhaust bolt pattern is the same?
I am considering that swap but remind my self that I have to do everything x 2

I appreciate the thought on E-bay as a source...I'll check it out.

i looked into setting up mine as a counter rotating drives. i read a few things online that it won't make much of a difference for the price tag that comes along with it. someone had a couple of Boston whalers that were identical and did the drive change to one. and he claims the ride quality didn't improve as much as he hoped.

Bowlner...I sort of expexted this...thanks for you feedback.

So...I think my optimal set up could be the SEI drives with 1.67 gearing turning a set of Revolution 4 Stainless with 21" pitch.

Once I get the drives on I'll hook up with BBlades on their demo plan and try a sey of 21" Revolution 4's to be sure.

i have a 255 sitting at the shop,belongs to a friend that has not been so good of a friend lately..in the middle of the resto he bailed so i put the boat outside with all new sbc's emi exhaust with through hulls.all new gauges and interior..he seemed to have lost interest..btw it has new gel from the water line up..if he dont pay me im going to part it out..

anyways the boat liked the laser II props, the cleavers seemed to not let the boat plane so well,we pur the laser II on and the boat jumped on plane..

i would stick with the 1.50 drives if you plan on using rev 4 props,i bet you will be braking the drives with the 1.6? retio..the 3 blades will be more forgiving because it wont bite the water so hard..