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-   -   suggestions on heads, cam, intake swap.. (https://www.offshoreonly.com/forums/general-q/302872-suggestions-heads-cam-intake-swap.html)

downforce137 09-12-2013 05:28 PM

suggestions on heads, cam, intake swap..
 
I have a '94 Rinker 236 with a carb'd 330hp 454, bravo 1 with a labbed 23p mirage+ that will run 60mph gps at about 4400rpms. I'd like to turn it closer to 5000rpms. I was thinking about swapping heads, cam, intake and exhaust over the winter and Im looking for some suggestions. Id like to keep the silent choice also..

http://i163.photobucket.com/albums/t...psd8494bae.jpg

ratman 09-12-2013 07:25 PM

what comp ratio is your eng now? and what cc are your heads, most perf cams want higher comp ratios to work well. you can get smaller chamber heads to bump it up using the oem pistons, run a roller cam, talk to a few of the engine builders that advertise on oso, have them spec you out parts that will work well together...rm

FIXX 09-12-2013 07:48 PM

fixx
 

Originally Posted by downforce137 (Post 3993690)
I have a '94 Rinker 236 with a carb'd 330hp 454, bravo 1 with a labbed 23p mirage+ that will run 60mph gps at about 4400rpms. I'd like to turn it closer to 5000rpms. I was thinking about swapping heads, cam, intake and exhaust over the winter and Im looking for some suggestions. Id like to keep the silent choice also..

http://i163.photobucket.com/albums/t...psd8494bae.jpg

your best bet would be is to just sell your engine as a complete runned and find a 502 mag efi ands go boating..your bottom ent wont last when you do any type of major mods to your engine..

Edit but because of the cast internals your limited to around 400 hp with the pee pee 3/8 rods..

now if your willing to do some modes to the bottom end then i would suggest to go with a 496 stroker kit with a forged crank and a nice set of forged pistone and i beam rods..you can get away with a set of 088 cast heads for now and with the rite cam and intake and carb you could get over 500 hp easily..

phragle 09-12-2013 08:06 PM

the 330 hast cast internals. there are many threads on building that motor up but you cant go far before you start picking up pieces of crank and spare rods out of the bilge.

downforce137 09-12-2013 10:23 PM

im surprised to hear the responses here. ive read many threads about 450-500hp 330hp 454's. the range on the sticker is 4600-4800rpms. i would think turning it 5500-6000rpms would blow it up, in no time, but thats not in my plan. I'd prefer not to go thru the bottom end at this time, as i only plan on keeping this boat for 2-3 more years before going to a 28ft.

phragle 09-12-2013 10:30 PM

Well if you plan on unloading it, keep it stock. If you start tweaking on a stock merc motor to increase performance you will decrease resale.

zeke 09-12-2013 11:38 PM

that hull was never meant to go fast, sell it buy a faster hull design.

Griff 09-13-2013 01:16 AM


Originally Posted by phragle (Post 3994996)
Well if you plan on unloading it, keep it stock. If you start tweaking on a stock merc motor to increase performance you will decrease resale.


Originally Posted by zeke (Post 3995013)
that hull was never meant to go fast, sell it buy a faster hull design.

I completely agree with them.

Heads cam, intake, carb and exhaust will run you more than 5k. It is simply not worth spending 50% of boats value to go 5 mph faster.

If you want more rpm, go to a 21" Mirage Plus or have BBlades lab the prop.

zeke 09-13-2013 06:17 PM

well I sure wish someone would of told be to buy a faster hull then try make my Baja 272 go fast LOL

MILD THUNDER 09-13-2013 06:39 PM

I'd like to see a true 500HP 454 CI that turns 4600-4800 RPM


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