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05-13-2009, 05:35 PM
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#1
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Mongo the Meet Coordinator
Join Date: May 2008
Posts: 16,938
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305 question
Worth it? 
In all seriousness, my family's boat has a wimpy 305 in it. My Dad wants to just drop a 350 shortblock in it but eh, theres gotta be stuff you can do to a 305 right?
I was thinking a nice heads/cam package, but I dunno how in the world you would pick that out, being as its a boat so it needs to idle and then get to WOT fast.
Ideas?
And it can't be more than like 380 hp or something, outdrive won't handle more than that.... which killed my nitrous idea... 
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Quote:
Originally Posted by KirkEvil
repo bigals turd gen and part it out to a loving home
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05-13-2009, 09:11 PM
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#2
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Join Date: Jun 2007
Location: Arm pit of the world... NJ
Posts: 2,677
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Here's what you do with a 305. Pull the crank out and throw away the rest. Put said crank in a 350 block with everything else from a 350 and go like hell.
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John
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05-13-2009, 09:17 PM
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#3
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Join Date: Dec 2008
Location: NNJ
Posts: 1,489
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i vote 350 or bigger 
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1997 Camaro Z28 - 355 LT1, T56, CC503, LTs, ORY, Bald Eagle-back exhaust, !emissions, Lingenfelter CAI, EWP, !CAGS, BMR LCAs, UMI PHB, Koni Str.t/Koni SA, C5 Z06 front / LS1 F-body rear brake swap, factory hurst with short stick 
2014 2LT Cruze 2.0 Turbo Diesel
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05-13-2009, 10:40 PM
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#4
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Mongo the Meet Coordinator
Join Date: May 2008
Posts: 16,938
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What would a 305 crank in a 350 do me?
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Quote:
Originally Posted by KirkEvil
repo bigals turd gen and part it out to a loving home
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05-13-2009, 10:51 PM
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#5
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Join Date: Aug 2007
Location: Long Branch NJ
Posts: 706
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Quote:
Originally Posted by Shownomercy
What would a 305 crank in a 350 do me?
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I think the journal size is different anyways. For a boat im sure you have to match peak power with the max prop speed. But yeah if the bottom end is good there really is no reason for a 350. 305 with heads and cam will make 300hp easily. But do you want to modfify a boat motor? They need to be reliable lol
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Formerly known as REED!
JSFBOA
Draino?
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05-13-2009, 10:52 PM
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#6
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Join Date: Aug 2004
Location: North Jersey
Posts: 3,047
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On the 1-piece rear-main blocks ('86-up) the 305 and 350 cranks are the same, just weighted differently. My guess is he's telling you to save the crank for the new motor. 
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Seeya,
Steve R. in North Jersey
'16 Go-Mango Dodge Charger R/T. It's so good to be back in a V8-powered, RWD car!
Former Toy - '88 Monte SS - had lots of mods...
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05-13-2009, 10:53 PM
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#7
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Mongo the Meet Coordinator
Join Date: May 2008
Posts: 16,938
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Ahh ok. Yea, idk, my Dad likes the warrenty of getting a new shortblock, but eh, I would rather not spend a lot of money on something I could do...
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Quote:
Originally Posted by KirkEvil
repo bigals turd gen and part it out to a loving home
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05-13-2009, 10:55 PM
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#8
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Join Date: Feb 2009
Location: bridgewater
Posts: 868
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put a snail on it
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05-13-2009, 11:01 PM
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#9
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Join Date: Aug 2007
Location: Long Branch NJ
Posts: 706
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a turbo wont help if the outdrive is the limiting factor. Thats the trans, rear, tires, and gear ratio all rolled into one. Just get a basic rebuild kit and rebuild the 305. Who cares about a warranty! Does the boat use a carb and HEI ignition? or some sort of fuel injection? It would prob benefit a lot from some fine tuning of the carb for constant throttle use. You dont really need throttle repsone or low end out of a boat motor. I would say go for used vortec heads, decent cam, and a single plane intake manifold. high 200hp at operating rpms, prob 320 at peak. Find a way to port the water jacket exhaust manifold things, or replace them. What kind of boat is it? I want to put a 50hp outboard on our boat. Its a 12ft aluminum 4 seater. Flies now with a 25hp....just imagine
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Formerly known as REED!
JSFBOA
Draino?
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05-13-2009, 11:01 PM
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#10
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Mongo the Meet Coordinator
Join Date: May 2008
Posts: 16,938
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Prob cost more than the shortblock, and then when the stock pistons blow up... yea... not a good idea. Marine gas = not so nice.
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Quote:
Originally Posted by KirkEvil
repo bigals turd gen and part it out to a loving home
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05-13-2009, 11:02 PM
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#11
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Mongo the Meet Coordinator
Join Date: May 2008
Posts: 16,938
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Its a 23ish foot formula.
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Quote:
Originally Posted by KirkEvil
repo bigals turd gen and part it out to a loving home
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05-14-2009, 08:43 AM
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#12
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Join Date: Jun 2007
Location: Arm pit of the world... NJ
Posts: 2,677
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305 and 350 crank are the same size.
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John
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05-14-2009, 08:47 AM
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#13
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Mongo the Meet Coordinator
Join Date: May 2008
Posts: 16,938
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Oh ok, cool.
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Quote:
Originally Posted by KirkEvil
repo bigals turd gen and part it out to a loving home
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05-14-2009, 09:22 AM
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#14
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Ayatollah of Rock N Rolla / Admin
Join Date: Mar 2006
Location: Parts Unknown
Posts: 12,573
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Quote:
Originally Posted by Featherburner
Here's what you do with a 305. Pull the crank out and throw away the rest. Put said crank in a 350 block with everything else from a 350 and go like hell.
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QFT.
Don't build a 305.
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05-14-2009, 09:24 AM
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#15
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Mongo the Meet Coordinator
Join Date: May 2008
Posts: 16,938
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Ok, well I guess I tried... lol..
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Quote:
Originally Posted by KirkEvil
repo bigals turd gen and part it out to a loving home
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05-14-2009, 12:30 PM
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#16
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Sliderule / Moderator
Join Date: Oct 2004
Location: Catawissa PA
Posts: 2,294
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You can't really do much with a 305, even getting to 350 HP is a bit tuff. The 305 is such a small bore that there is no room for big valves so it just can't move air and breath.
The 305 HO/TPI heads (or something simular) have slightly larger values and thus flow a bit more, adding a mild cam will put you in the 210-235HP range. Also remember that 305s aren't designed to be spun high, keep it under 6K or you run the risk of cracking the mains.
So as others have said, unless you are running some type of class where you would be restricted to a 305 a 350, even a mild 350 would be cost effective and able to be spun higher. And don't waste the money on strocking a 305, we played with them (334 CI ) back in the 80's and a mild 250 will still pull better numbers at 1/2 the cost.
Not really a boat person, but can't you change props?
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93Z M6 Black: The 385 Lives! Supercharged, 3-core front mount intercooler, GTP heads, 3:73's, Street twin clutch, Jethot Longtubes, Mufflex 4" catback/spintech, S+W cage, Spohn Suspenion, Yada Yada Yada
1) Build it
2) Race it
3) Break it
4) Repeat!!!
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05-14-2009, 12:42 PM
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#17
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Mongo the Meet Coordinator
Join Date: May 2008
Posts: 16,938
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Yup, same as a car pretty much, new gears in the outdrive, and at the moment we run a four blade prop for get out of the hole oomph, versus a three blade for top end speed.
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Quote:
Originally Posted by KirkEvil
repo bigals turd gen and part it out to a loving home
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05-14-2009, 01:07 PM
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#18
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Join Date: May 2005
Location: under a roof
Posts: 2,034
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1973 Chevy Nova - best e.t.-10.04 - currently disassembled
1989 Pontiac Trans Am GTA
2016 Dodge Durango R/T
2015 Ram 3500 Dually Cummins
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05-14-2009, 01:09 PM
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#19
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Mongo the Meet Coordinator
Join Date: May 2008
Posts: 16,938
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Expensive.
But yea, my Dad has a ton of engines he likes picked out... and lucky me, I get to play swap this winter/late summer. Woot.
__________________
Quote:
Originally Posted by KirkEvil
repo bigals turd gen and part it out to a loving home
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05-14-2009, 02:32 PM
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#20
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8 Second Club
Join Date: Jun 2006
Posts: 4,315
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Quote:
Originally Posted by Pampered-Z
You can't really do much with a 305,
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not true. i had a 305 and in all seriousness it was faster then some of these LT1's LS1's. 13.1 on motor 11.47 on a 150 shot.
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05-14-2009, 02:34 PM
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#21
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Mongo the Meet Coordinator
Join Date: May 2008
Posts: 16,938
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See heres the thing Bill.... as much as I would love to spray the snot out of my Dad's boat, I think I would fail a few safety things and or, cost a lot every re fill.... lol
__________________
Quote:
Originally Posted by KirkEvil
repo bigals turd gen and part it out to a loving home
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