View Full Version : Re-Power 28ZX

05-09-2012, 12:07 PM
Engines are in, still waiting on the interior......couldn't stand it anymore, launched Monday afternoon with my old Mirage plus 23p 3 blades hit 74 at 5400rpm, it was a little uncomfortable in the Gulf with no seats or engine cover but MY LORD those 383 strokers have a crap load of power and torque over the 350's. I picked up some Hydromotive 4 blade labbed 25p to try to reduce rpm 200 and get a little more speed, I think I'll wait for something to sit on for the next test.71435

roadtrip se
05-09-2012, 01:03 PM
We actually had a father and son team show up one year at AOTH with a Z-29 that had no interior, just plywood. They ran it that way all weekend. When they did finish it later with a custom interior, it looked awesome.

In terms of testing, just remember the interior is going to add weight and impact the CG, if you do decide to go for another ride!

Have fun with it!

05-10-2012, 12:37 PM
+1 on the weight. that back hatch cover seems like it weighs a ton.

They look good too. Can't wait to hear numbers in the end. Technically the engine should be just about dead on to the original Scorpion ZX's so you probably should get in touch with one of the members that have them for prop suggestions. I think I remember reading the prop of choice for top end is 27p labbed Mirage +

Greg K
05-10-2012, 02:42 PM
Nice re-power...these 383's are reman'd by Mercury, rated at 350 hp @ 5200 rpm

05-10-2012, 05:17 PM
Keep us posted on the props. You plan on turning them in or out?

05-10-2012, 05:39 PM
I picked up a set of Hydromotive 26p 4 blade's that are labbed and re stamped 25p. I am going to give them a try to lower the RPM hopefully pick up some speed, I also have the worlds worst bottom paint job (I wish I could slap whoever did that) soda blasting is my next project after the interior is back in and will let you all know what's working....

Greg K
05-10-2012, 07:30 PM
You may want to try this stripper, reviews are very good, Franmar Soy Strip (http://www.franmar.com/shopping/index.php?main_page=product_info&products_id=71)

05-23-2012, 09:24 AM
allright finally got the interior back in, tried the 25 labbed Hydromotive 4 blades, 4900 rpm at 70, does any one here have any experience with 5 blade props from Southern Ca? I think I need 24 pitch to get to 5200 rpm or will the extra blades reduce the rpm also? my 3 blade 23p Mirage plus ran 5400 rpm at 75, will adding 2 more blades reduce the rpm or do I need to step up 1 pitch also?71639

05-23-2012, 01:51 PM
Do you want top speed, best cruise, best all around?

For top speed it's pretty well documented that the best you'll get is on Mirage + props. you just need a bigger pitch. I seem to remember that 27" labbed M+'s are the fastest on factory scorpion boats... and your power is now the same, so I'd think that is where you want to be. Stock 25 pitch M+'s would work well too.

More blades mean more drag so the lowest number of blades that you can run generally nets you the highest speed. However, slip can be better with more blades so if cruising is important adding the 4th blade is nice. For example I run Bravo 1 4 blade props, awesome cruise and easy planing... the trade off is lower top end. I can pick up 5-ish MPH with Mirage plus props but they plane like crap on my boat (1.65 drives I'll attest it to) and the cruise is lower. The few times I go top end is not worth the loss in cruise or drive-ability where I boat.

05-23-2012, 04:13 PM
is the 383 stroker the same block as the 6.2? i think the 6.2 is a 377ci engine, also r the stroker engines fuel injected?

05-24-2012, 09:04 AM
Thanks for the help guys, top end is important the wife and I are both speed freaks (she tests for Jack Roush Jr. and wants to put Whipples on both engines) I will try the different pitch to get a good all around prop. Fisherman from what I was told the 383's are 350 blocks bored and stroked for more cubes 350 to 383ci, and yes mine are fuel injected but you can get carb engines also.
Thank you for your help