Old style 4.3L V-6 vs. Vortec 4.3L V-6

[TheHole]

I have a 1987 ArrowGlass 21' bowrider with a 175 hp 2bbl 4.3L V-6. Launch is good but wide open top speed is only 34 mph and cruises 24 mph @ 3000 rpm. I can get hold of a 225 hp Vortec 4.3L engine. My questions that I need knowledgeable opinions on are 1.) If I up-power will I truly notice 50 hp, someone told me that a 4 bbl carb and bumping the timing could even get more. 2.) Can I change my 14p prop to a larger prop and gain cruise and wide open MPH? 3.) Would keeping the engine weight the same with more HP be as good as going to a heavier V-8 with more HP?

 

[hall832]

Re: Old style 4.3L V-6 vs. Vortec 4.3L V-6

Start with your prop, It can make a huge difference. You have a good hole shot? Want more top end.

 

[TheHole]

Re: Old style 4.3L V-6 vs. Vortec 4.3L V-6

Start with your prop, It can make a huge difference. You have a good hole shot? Want more top end.

I have a good hole shot, it had the wrong prop when I got it and would not achieve full RPM. I got it dialed in and I was told because it is a heavy boat that was it for top speed.

 

[Bt Doctur]

Re: Old style 4.3L V-6 vs. Vortec 4.3L V-6

we need to know the max rpm ,thats what tells you about props.

 

[TheHole]

Re: Old style 4.3L V-6 vs. Vortec 4.3L V-6

4600 rpm

 

[Fun Times]

Re: Old style 4.3L V-6 vs. Vortec 4.3L V-6

I have a 1987 ArrowGlass 21' bowrider with a 175 hp 2bbl 4.3L V-6. my 14p prop to a larger prop and gain cruise and wide open MPH?

4600 rpm

Hi there, Welcome to iboats! Your question would seem more like a prop thread vs an engine thread. So for now due to the nature of the question, we're going to need to move this thread up one forum section to the Non-Repair I/O and Inboards Discussions not involving troubles or repair as it's more of a question of what will work better vs an how to "fix" something.

One important question though would be what is the gear ratio of your stern drive as a 14 pitch prop is not all that common to be using on a properly geared drive.

Looks like your boat is around 3500 lbs?
1987 Arrow Glass Boat & Mfg Corp Prices & Values - NADAguides

 

[jkust]

Re: Old style 4.3L V-6 vs. Vortec 4.3L V-6

Yes, you will notice it and in addition back in the day, HP was measured at the flywheel and now it is measured at the prop....meaning more prop hp than the comparison would indicate on its face.
4bbl on a v6 isn't going to get you there without a cam, etc.
I don't think so because the torque curve is flatter and higher on the V8. While for example a 5.0 v8 can have the same hp as a 4.3 v6, the torque curves tell a different story. We generally don't discuss torque in Marine applications however, but the curves are published.

 

[Bondo]

Re: Old style 4.3L V-6 vs. Vortec 4.3L V-6

I have a 1987 ArrowGlass 21' bowrider with a 175 hp 2bbl 4.3L V-6. Launch is good but wide open top speed is only 34 mph and cruises 24 mph @ 3000 rpm. I can get hold of a 225 hp Vortec 4.3L engine. My questions that I need knowledgeable opinions on are 1.) If I up-power will I truly notice 50 hp, someone told me that a 4 bbl carb and bumping the timing could even get more. 2.) Can I change my 14p prop to a larger prop and gain cruise and wide open MPH? 3.) Would keeping the engine weight the same with more HP be as good as going to a heavier V-8 with more HP?

Ayuh,.... Welcome Aboard,.... Is this a bare Long block motor, or Fully Dressed Bobtail motor,..??

If fully dressed, with What, 'n by Whom,..??

I'm with Fun Times, it sounds like ya got a V8 geared drive behind yer V6,....

 

[TheHole]

Re: Old style 4.3L V-6 vs. Vortec 4.3L V-6

It is a complete block with heads. Low hours but I will go through it and get an intake before I drop it in. I will verify the drive ratio tonight.

 

[Bondo]

Re: Old style 4.3L V-6 vs. Vortec 4.3L V-6

It is a complete block with heads. Low hours but I will go through it and get an intake before I drop it in. I will verify the drive ratio tonight.

Ayuh,.... That's called a Long Block,...

A Complete motor is a Bobtail, which Has the Dressin's on it, induction, ignition, 'n manifolds,...

It's Alot newer than yer '87, 'n many of the Dressin' off yer '87, won't fit the newer motor, besides the intake ya already know 'bout,...

 

[TheHole]

Re: Old style 4.3L V-6 vs. Vortec 4.3L V-6

It's a 4.3L 175 hp engine, 1.81:1 ratio drive, 14"x14p prop, pushing 34 mph @ 4600 rpm.

 

[TheHole]

Re: Old style 4.3L V-6 vs. Vortec 4.3L V-6

It's a 4.3L 175 hp engine, 1.81:1 ratio drive, 14"x14p prop, pushing 34 mph @ 4600 rpm.