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i have a 20ft reinell with a omc cobra 302 in it i believed it was a 205hp but after doing some searching it is actually a 160hp . the boat ran around 45mph at 4600 this summer. this 302 has the standard fireing order not h.o. with a 2 barrel. i will be changing the haeds from the staock 70cc heads to 63cc 87-93 mustang heads, as well as a h.o cam with different fireing order and edelbrock performer manifaold with a holley 4 barrel. i believe from the research ive done i should bump up compresson from the heads to about 8.75 or 9.0 from the stock of 8.0. horsepower should be around 260 -270. my question is a mid 50's to 60mph out of the question ill be trying either a 21 or 23p prop. this hull desingn is a lot like a mirage of simalar years. any suggestions on my set up would be greatly appreciated.thanks
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Asking way to much. :frown: A 10 mph gain is going to take lots more power. You can change the props all day and it will not get you what you are asking for
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For a baseline guide, I had a '92 20' Blue Water(same hull). 350 mag Alpha 1.5 was at 55 mph(58 indicated). 265 hp 250@prop I believe. Over the years took it to 70 mph with heads, cam, MSD, 800 Holley, thru hull, 1.5 Bravo and a 144 B&M @7 lbs. spinning a 25p at 5200. Chine walk around 68 mph and up. :wink:
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i really dont have the money to go with a super charger but the numbers you were getting prior to super charging would be sufficient for me in this boat im glad to here 55 may not be out of the qusetion id like to cruise at my topspeed now then be able to go 55. one more question what type of prob did you use my boat doesnt seem to have much bow lift feels like its dragging, i am expierenced with trim ive had many boats this just feels goofy for lack of better words, im now thinking maybe the low stock horsepower might be the prob (160hp) but what has impressed me was the boat is a ble to to even 45-46 with that low of power. any suggestions would be greatly appreciated im willing to do just bout anything motor wise that isnt going to break the bank cam suggestions and intake would help to thanks . Aaron
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Hmmmm...Heads and cam will not likely get you where you want. I would say go to a stroker 347 and maybe GT-40 heads if they're not too big. Not really up on sbf stuff. Performer intake fine, Edelbrock 600 marine carb. is lots cheaper than Holley and would work good. Cubic inches and torque are what you're after, and the only thing that will guarantee more speed.(other than s/c). Cam company should be able to steer you in right direction once they know your particulars. DON'T go too big on cam or heads, build for max. rpm 5200. The 205 hp 4.3 V6 was good for 50mph as I recall. BTW, my old boat is now a 383, and is nudging an out of control 75mph according to owner :smile:
Actually had lots of fun in the old tub, easier to suck the lesser boats into a race :cool: Most stock big blocks run around 65mph in 22' v-hulls.
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On the trim thing, yes this is a wide hull and not very efficient. I found using a small diameter prop(in my case a 13.25X 25 5-blade) allowed me to trim the $hit out of it and it picked up speed. Of course it contributes to chine walk once above 65mph.
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just to touch base back on the the numbers i got this summer . the final setup i used was a comp cam 256 4x4 extreme with 351 fireing order , 1990 mustang heads milled .030 thousands, 600 holley and a performer manifold. after trying multiple props i ended up with a mirage 19p , cant say enuff about john at the prop shop in mukilteo. Anyways its by no means a screamer but i did get 56.8 on a gps after lots of trial and error with 2 people in the boat . The timeing seemed to be critical. hopefully ill be getting a mid 90's baja or checkmate with a 454 soon.
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just to touch base back on the the numbers i got this summer . the final setup i used was a comp cam 256 4x4 extreme with 351 fireing order , 1990 mustang heads milled .030 thousands, 600 holley and a performer manifold. after trying multiple props i ended up with a mirage 19p , cant say enuff about john at the prop shop in mukilteo. Anyways its by no means a screamer but i did get 56.8 on a gps after lots of trial and error with 2 people in the boat . The timeing seemed to be critical. hopefully ill be getting a mid 90's baja or checkmate with a 454 soon.
Those are respectable numbers from the 302, nice job.
I know of an incredible Baja 25 Outlaw for sale, it is mint and I mean MINT condition. EFI procharged 502 mag. bravo 1. Owners name is Tim, he organizes the Portland poker run. Let me know if you want more info.
http://www2.***boat.com/image_center...31DSC00165.jpg
