What makes an engine a "Vortec" and what dif does it make?

[tmh]

Just curious....I recently bought a used Mercruiser 350 engine from someone who seemed to know engines a bit - he had pulled it from his boat because the boat was falling apart. It was not the original engine so he didn't know the exact age of the engine, estimated 1987-1992 based on serial #.

Anyhow, as we're loading it into my truck he says that it's a Vortec engine which he wasn't aware of (hadn't looked closely or had forgotten, i don't know). He pointed out some bolt pattern that meant nothing to me and I just nodded. It seemed to me by the way he said this that this was a good thing for me as the buyer. basically, he said something to the effect of, "darn, i could have got more for this knowing that" but wasn't trying to push me up on price or anything.

Anyhow, I didn't ask him, but what exactly does a Vortec engine mean and what is the difference from any other merc 350 engine? He originally said it was a 350 Mag....can it be a Mag and Vortec? Thanks.

 

[bishop1976]

Re: What makes an engine a "Vortec" and what dif does it make?

Vortecs didnt come out until 1996 I dont think. At least that is the first year they showed up in Chevy trucks.

 

[Mkos1980]

Re: What makes an engine a "Vortec" and what dif does it make?

Vortec heads and intake is the differance. Vortecs are a little more powerful due to the head design and taller intake ports.. The bolt battern is is talking about is on the intake. 2 bolts in each corner run straight down holding the intake to the heads vs the older SBC which use 6 bolts per side on an angle. You can have a 350 Magnum in the older style and vortec style.

 

[tmh]

Re: What makes an engine a "Vortec" and what dif does it make?

OK, thanks. i'll check the bolt pattern out myself when I'm at the mechanic's shop where the engine is.

Just to add background, this engine came off a 1985 boat. However, it is likely NOT the original engine. The boat was a performance type boat, had thru-hull exhaust (not sure if original or a mad) and was a "very fast boat". The guy I bought it from had only owned the boat for 5 years and he did not know the history of the engine. It may well have had mods or a re-power after 1992, we have no idea. The timing of when a vertec style was available for Mercruisers engines may shed some light on this.

 

[Bondo]

Re: What makes an engine a "Vortec" and what dif does it make?

Ayuh,.....

As noted above,... The Chevy Vortec heads were Intro'ed in 1996 on the SBCs,... Both the V8s,+ the V6s,....
They're a Fast Burn combustion chambered head with taller intake ports,....
They're good for a 20/ 30 hp increase over the old style heads,...

Merc started using them as they made their way down the pipeline to them.....
Some in 96,+ most all from 97 on....

 

[TilliamWe]

Re: What makes an engine a "Vortec" and what dif does it make?

Just to put all the Vortec specific things in one post:

1) Vortec heads
2) 8 vertical bolt intake manifold
3) Roller camshaft!

and yes 1996 introduction.

 

[wncrjb]

Re: What makes an engine a "Vortec" and what dif does it make?

Somewhere starting around 1992 the "vortec" name was being stamped into the valve covers with the introduction of the balance shaft engines.These engines still had the stamped steel valve covers and timing cover using 10 bolts. The intake manifold used 12 bolts to hold it to the head.

In the 1996 production year, the new style vortec head was introduced which uses 8 bolts on the intake. This engine also uses the composite timing cover that uses 6 bolts along with composite valve covers.

I have (2) 4.3 V-6 engines from 1992 that say "vortec" on the stamped steel valve covers.......

wncrjb

 

[TilliamWe]

Re: What makes an engine a "Vortec" and what dif does it make?

That's V-6 only stuff. The V-8s still get the steel valve covers and timing chain cover. But yep, I remember those first 4.3 Vortecs, some were rated at 200hp in S-10 Blazers. They later backed off of that and rated everything at 195.

 

[mrmushroomman]

Re: What makes an engine a "Vortec" and what dif does it make?

Mine is a 1995 and it is a Vortec and was proably manufactured in 1994 so there were some before 1996.

 

[Bondo]

Re: What makes an engine a "Vortec" and what dif does it make?

Mine is a 1995 and it is a Vortec and was proably manufactured in 1994 so there were some before 1996.

Ayuh,.....

Are you basing this on just having the word "Vortec" written on the Valve Covers,..??
Or,...
Do you have Only 8 bolts holding the intake to the heads......

Because, as noted by wncrjb,...
Chevy was using the Name "Vortec" for a few years Before the Fast-burn Heads were intro'ed.......
If your motor does in fact have an 8 bolt Intake,..... The motor is Newer than you think....

What We know today as Vortec Heads were introduced in 1996..........

 

[tmh]

Re: What makes an engine a "Vortec" and what dif does it make?

Good info guys, thanks. Maybe my engine is newer than i thought or mods were made since 1996, I'll check the serial numbers when i get a chance to see the engine.

What does the vortec DO differently than a non-vortec? Is it more fuel efficient or just a bit more power? Would the 350 vortec Mag put out about 270-280 hp?

 

[TilliamWe]

Re: What makes an engine a "Vortec" and what dif does it make?

It flows air better, due to the roller cam profile and the efficiency of the Vortec heads.
A 350MAG MPI is supposed to be 300hp.

 

[John_S]

Re: What makes an engine a "Vortec" and what dif does it make?

A 350 marine vortec w/4brl carb will put out about 280hp at the prop.

 

[Silverado6x6]

Re: What makes an engine a "Vortec" and what dif does it make?

I have an 8.1 Vortec in my Silverado, stock 340 HP. The block was designed as a marine engine and from what i know I could take it out of my truck and use it in a boat with adapted cooling systems.
http://www.airboats.com/pages/8100_stnd_specs.html

http://powerandmotoryacht.com/engines/0101vortec/

 

[tmh]

Re: What makes an engine a "Vortec" and what dif does it make?

A 350 marine vortec w/4brl carb will put out about 280hp at the prop.

OK, thanks John. That's what I have (I think, need to confirm when I see the engine next week).

 

[wncrjb]

Re: What makes an engine a "Vortec" and what dif does it make?

Mine is a 1995 and it is a Vortec and was proably manufactured in 1994 so there were some before 1996.

Is yours a v6 or v8 ?

how many bolts hold the intake to the heads?

wncrjb

 

[JCF350]

Re: What makes an engine a "Vortec" and what dif does it make?

Vortec actually refers to the style of intake assembly (variable intake) for the engine, other upgrades such as the heads came later.

 

[Rock Hall]

Re: What makes an engine a "Vortec" and what dif does it make?

For curiousity, I have a '94 Olds Bravada. Motor says Vortec. I also previously owned a 95 4.3 in a different vehicle. This intake on the Vortec looks higher. Does his 94 4.3 have the Vortec heads or just a different manifold?
Thanks for the info.
Mark

 

[Silvertip]

Re: What makes an engine a "Vortec" and what dif does it make?

As early as 1992 the 4.3 "W" series motors were Vortecs and had balance shafts. They were also CPI (central port injection) or better known as "spider" injectors because the entire assembly looked like a spider. These engines were most common in Safari/Astro Vans with All Wheel Drive.

This is what can be done with a 4.3 and enough money.

http://www.youtube.com/watch?v=Q5ej6SPKk3w&NR=1

 

[RCSConstruction]

Re: What makes an engine a "Vortec" and what dif does it make?

I don't think your getting 280 at the prop. More like flywheel.?
Unless the drive loss is really low?
I was told a stock carb'd vortec 5.7 is 260-275 hp (flywheel) and the FI motors put down 300-315hp.
Add a mild cam and roller rockers to the stock vortec and your into 300.

Also wanted to add it's quite popular to bolt on vortec heads to a non vortec "era" block but your not getting the full power that a vortec motor puts out. The vortec's have a more aggressive cam and it's a roller with roller lifters.