Mercruiser repower with Vortec or non Vortec

[michael-tuttiett]

Hi folks, after some advice here... We 'put a leg out of bed' last weekend in out 1994 190hp 5.0 (2bbl) merc alpha1, g2.. 815hours.. Very sad indeed..She is completely dead. After much research, I have decided to repower with a remanufactured 5.7 long block -

I can buy either a non vortec or a vortec engine for the same price from the same supplier. The vortec will take my mechanical fuel pump but I will have to buy a new inlet manifold and carb. Not a worry there..

I have had varying advice about which way to go - one says go vortec - later technology, more power, more economical etc...
The actual supplier of the engines says keep it simple, that the power and economy gains are marginal between the two and that the pre vortec gives less trouble and may be more reliable.

I also don't want to run the risk of ruining my alpha 1 gen 2 out drive. Bearing in mind it also has 815 hours on it.

I need to make a decision and order the engine. Overall I want longevity. I want something that can last and I want to minimise the possibility of issues arising.

Can anyone offer some advice on which is better?

 

[michael-tuttiett]

No Title

 

[geneseo1911]

The actual supplier of the engines says keep it simple, that the power and economy gains are marginal between the two and that the pre vortec gives less trouble and may be more reliable.

Your engine builder is an idiot. I'd re-consider using him if I was in your shoes. The Vortec engine is simply a modern head that takes advantage of discoveries in airflow, mixing, and flame front propagation to make the old SBC design WAY more efficient. Consensus on this forum is 30-40 HP from the head swap alone. No reliability issues; the difference is in combustion chamber design, nothing else. Vortec heads will bolt to any SBC; only the intake manifold is different.

An otherwise stock Vortec 350 will be running in that 300HP neighborhood, which is the max safe level for the Alpha drive. Keep the oil changed and don't punch the throttle wide open every time (good advice for ANY outdrive) and it will be just fine.

I kinda wish my '82 350 would have a problem so I could drop a Vortec 383 in its place, but it runs so good I can't justify it.

 

[Bondo]

Hi folks, after some advice here... We 'put a leg out of bed' last weekend in out 1994 190hp 5.0 (2bbl) merc alpha1, g2.. 815hours.. Very sad indeed..She is completely dead. After much research, I have decided to repower with a remanufactured 5.7 long block -

I can buy either a non vortec or a vortec engine for the same price from the same supplier. The vortec will take my mechanical fuel pump but I will have to buy a new inlet manifold and carb. Not a worry there..

I have had varying advice about which way to go - one says go vortec - later technology, more power, more economical etc...
The actual supplier of the engines says keep it simple, that the power and economy gains are marginal between the two and that the pre vortec gives less trouble and may be more reliable.

I also don't want to run the risk of ruining my alpha 1 gen 2 out drive. Bearing in mind it also has 815 hours on it.

I need to make a decision and order the engine. Overall I want longevity. I want something that can last and I want to minimise the possibility of issues arising.

Can anyone offer some advice on which is better?

Ayuh,..... Welcome Aboard,.... You've answered yer own question,.....

No reason in the world, Not to go Vortec,....

Free horsepower, 'n much Better Efficiency,....

 

[michael-tuttiett]

My main concern then is my alpha 1 drive. Will this 20 year old 815 hrs gen 2 take the horsepower and torque of my new vortec? I'm not so worries about weather i have 270hp or 300. I just don;t want to be replacing my drive anytime. Would I be safer to keep away from the 300hp mark?

thanks for your comments geneseo1911... I also have a Cobalt and LOVE IT

 

[michael-tuttiett]

My main concern then is my alpha 1 drive. Will this 20 year old 815 hrs gen 2 take the horsepower and torque of my new vortec? I'm not so worries about weather i have 270hp or 300. I just don;t want to be replacing my drive anytime. Would I be safer to keep away from the 300hp mark?

thanks for your comments geneseo1911... I also have a Cobalt and LOVE IT

 

[geneseo1911]

I admit I don't have the experience of a lot of guys on here....but I've read of folks running 400 HP on an Alpha for years. A little bit of caution is all it takes. Mercruiser put a 330 HP big block in front of an Alpha drive for a few years, but there was some breakage, although from time to time someone will pop up still running one. I would bet most of the broken ones were due to abuse and/or lack of maintenance, which the big block was less forgiving of/ The generally accepted limit is 300 HP, but like I said, I wouldn't hesitate to put 350+ HP in front of one with a little driver care. At the 300HP level (which is where I THINK mine is), I wouldn't even think twice.

 

[michael-tuttiett]

further to the discussion, I have been to the shed tonight to see what the drive ratio is. it's a 1.65r. does this affect anything?

 

[geneseo1911]

How big is the boat? Usually the big V8's were 1.47:1. You might have to go clear up to a 23-25 pitch to keep the RPM's in range unless its a big/heavy boat, but you should be able to make it work.

 

[michael-tuttiett]

The boat is a 20 foot Cobalt, so quite a heavy unit... well heavier than a Bayliner...

I was doing dome digging around and discovered that only the baby of baby V8s (mine -the 190hp 5.0) had the 1.65 ratio which they shared with the 4.3. There are a lot of varying opinions as to weather changing a prop will compensate. Could this be another reason to keep away from the 5.7vortec with all it's horses? or maybe go for a 5.0vortec instead?

Can i buy a 1.47 gear set for my drive?

This project is becoming so complex... kind of fun finding out all there is to know but stressful too. I had always planned a re-power eventually but not so soon. Timing has affected my budget.

 

[geneseo1911]

I wish one of the more knowledgeable members would offer some opinions, as I'm always afraid of telling someone wrong, BUT if I was in your shoes, I'd drop in as much power as I could afford, and prop it to match. It seems to me like the prop will make up for the gearing and vice-verse, which is how a 140 HP 4 cyl. swings the same 21" prop as a 260HP V8. I THINK as long as you can get a prop to keep the RPM's in the right range, it doesn't matter what gears you have.

My 19' Cobalt with a slightly breathed on Mercruiser 260 runs a 21P stainless prop on the high end of rated speed at 55ish MPH. I suspect with your gear ratio and power in a similar sized boat you're going to need a 23 or 25 like I mentioned above and run a similar speed. This would be a good question for the prop recommendation forum. They might be better able to advise you on the gear ration issue as well.

190 to 300 or so will make a different boat out of her....

 

[Rick Stephens]

190 to 300 or so will make a different boat out of her....

Oh boy.

Understatement of the month.....

 

[Bondo]

The boat is a 20 foot Cobalt, so quite a heavy unit... well heavier than a Bayliner...

I was doing dome digging around and discovered that only the baby of baby V8s (mine -the 190hp 5.0) had the 1.65 ratio which they shared with the 4.3. There are a lot of varying opinions as to weather changing a prop will compensate. Could this be another reason to keep away from the 5.7vortec with all it's horses? or maybe go for a 5.0vortec instead?

Can i buy a 1.47 gear set for my drive?

This project is becoming so complex... kind of fun finding out all there is to know but stressful too. I had always planned a re-power eventually but not so soon. Timing has affected my budget.

Ayuh,.... The Alpha will handle the Vortec 350, with a 4bbl. carb, or Efi if ya really wanta spend some coins,....

You'll have to prop up to probably a 25", 'n add more cup to hold the rpms with the 1.65 gears, but it's doable,....
As for swappin' the gears, a New Sei upper unit is Cheaper,....