305 vs 350?

[user64]

I have a 26 foot boat w/ volvo 1999 5.0 RWC 220hpHas always been marginal on power plus engine has seen better days Was thinking of upgrading to a 350 (5.71) but see so many variations i.e 350-260 hp, 350-300hp . I even see a 5.0 rated at 270hp. What is the best move here? Basically just fish etc with 1 or 2 others on the boat...no water skiing .

 

[Bondo]

Re: 305 vs 350?

What is the best move here?

Ayuh,... Buy a 350 Long Block,+ swap over all the acc. parts off your 305...
It's the same money or Cheaper,+ you get Free Horsepower...

 

[Gary H NC]

Re: 305 vs 350?

If you are replacing it anyway just go with a 5.7 block.All your tins will mount right over to it.Intake manifold and all.Being a 99 is it already a Vortec?

Dang Bond-O......fast one finger pecker you!....LOL!!!

 

[user64]

Re: 305 vs 350?

Not sure about the Vortec question. It has a 2 bbl Holley and a lot of the other items (alternator , power steering pump are extremely rusted) so I was looking at Doug Russell and Marine power service engines catalog figuring I would need a new manifold and 4 bbl carb anyway...but then saw all the different 5.71 configurations plus the 270hp 305 and am not sure what the best move would be.

 

[Bondo]

Re: 305 vs 350?

and am not sure what the best move would be.

Ayuh,... In that case,... A 350 dressed Any way you'd like it.....

 

[ryendube]

Re: 305 vs 350?

just toss a 350 crank in that 305, port her out and dial it in. have a sweet 327 stroker ...... oh crap this isnt the hotrod forums...


no replacment for displacement. bigger motor will give bigger power. go 5.7 if your complaining about lack of power. they are identical blocks just larger bore and larger valves in head.

 

[wca_tim]

Re: 305 vs 350?

any passable set of heads with an aluminum intake and 4 barrel combined with a 383 bottom end would make a good deal more power - especially torque - than a 305 or even a 350 for not a ton more money than a 350 longblock. Might be worth looking into...

 

[Mkos1980]

Re: 305 vs 350?

just toss a 350 crank in that 305, port her out and dial it in. have a sweet 327 stroker ...... QUOTE]


305 and 350 have the same crank but they are balanced differantly. You want a 3.75 Crank. That would equal a 334 SBC

 

[ryendube]

Re: 305 vs 350?

just toss a 350 crank in that 305, port her out and dial it in. have a sweet 327 stroker ...... QUOTE]


305 and 350 have the same crank but they are balanced differantly. You want a 3.75 Crank. That would equal a 334 SBC

amm i mixing up the 350 400 383 set up?

a true 327 is a 4" bore with a 3.25 crank im mixing the common bore size of a 350 and 327....307 crank in a 350 makes it...... my bad.

 

[fabrimacator21]

Re: 305 vs 350?

A 327 is a bored out 307. Only the 307 and 327 used the 3.25" crank. Nice little high revving motors. The 305 and 350 use a 3.480" stroke crank.

Theres no reason to start getting into strokers.... just get a 350. In a 26ft boat you want as much tq as you can get and unless you want a 383 then stick with the tree fitty. Cheap easy upgrade in power.

Only reason I'm hot rodding a 305 is to keep the tq to a minimum to save the I/O. If I had a beefier I/O I'd throw a 350 or 383 in there in a heartbeat. 305's get better mileage also... I know a guy who went from a 305 to a 350 and he said his gas mileage plummitted. However I'm talking 18ft boats. Yours is a 26ft so the 350 is a no brainer.

Like bondo said, just buy a 350 longblock and swap over your accessories. You'll be money ahead.

What I/O do you have? You might want to keep an eye on the "roof" for your I/O... I.E. how much power it can take.

 

[ryendube]

Re: 305 vs 350?

A 327 is a bored out 307. Only the 307 and 327 used the 3.25" crank. Nice little high revving motors. The 305 and 350 use a 3.480" stroke crank.

Theres no reason to start getting into strokers.... just get a 350. In a 26ft boat you want as much tq as you can get and unless you want a 383 then stick with the tree fitty. Cheap easy upgrade in power.

Only reason I'm hot rodding a 305 is to keep the tq to a minimum to save the I/O. If I had a beefier I/O I'd throw a 350 or 383 in there in a heartbeat. 305's get better mileage also... I know a guy who went from a 305 to a 350 and he said his gas mileage plummitted. However I'm talking 18ft boats. Yours is a 26ft so the 350 is a no brainer.

Like bondo said, just buy a 350 longblock and swap over your accessories. You'll be money ahead.

What I/O do you have? You might want to keep an eye on the "roof" for your I/O... I.E. how much power it can take.

i wasnt bein serious. I did say just get the 5.7

ya i did realize my error 307 with 4" bore ( 307 had the large journal crank for most as far as i can remember, production 327s used small journal. cept for a couple years)

 

[user64]

Re: 305 vs 350?

Thanks to all for the input. As far as the outdrive, its an SX (not duo prop)and has pretty much been bulletproof. I know they are ok to pair w/ a 350. Someone also mentioned that I might want to switch the lower gears, shaft etc and convert it to a duo prop. I can always do that at some point if I wanted more but would wait to see how it went with just the 350 swap

 

[gadget73]

Re: 305 vs 350?

I'd be looking at a later 350, the Vortec type. Those use a specific intake manifold, but the heads kick butt and make a lot more power. That really is the big difference between the 300 hp 350 and the 260 hp 350: the heads. Same deal on the 305, better heads and the 4bbl. 300 hp 350 with the correct intake and 4bbl sounds like a nice upgrade to me.

 

[jze1212]

Re: 305 vs 350?

The Vortec heads have an 8 bolt intake manifold, the bolts are vertical too. Good luck with whatever you decide to do

 

[Mkos1980]

Re: 305 vs 350?

Go vortec heads. you wont be sorry. I took my 260HP Merc, tossed on the vortec heads , 4bbl and a hot roller cam and I couldnt be happier. It accually idles smoother then stock, has more tq and of course more power. When I have the engine exhaust through the prop, you would never ever know something else is under the doghouse.

 

[fabrimacator21]

Re: 305 vs 350?

Another vote for the vortecs.

 

[mkast]

Re: 305 vs 350?

What is the best move here? Basically just fish etc with 1 or 2 others on the boat...no water skiing .

In a twenty-six footer, even an eighty horsepower increase, might net you seven or eight miles per hour, on a good day. Take the money for the refit, (more than you think) add your boat to it and get a boat more to your liking.
Or, go fishing and live with it. But I have to ask, when you acquired the boat, did you think two hundred twenty horsepower in that size hull would, "BE OK?"