The difference of a vortec

[sjarrett71]

These might seem like silly questions but I'm going to ask them anyway. What is the main difference between regular and vortec heads? Are the heads the only difference in a "vortec" engine? Can you use vortec heads on a regular block? If so, how? Will a regular intake manifold fit vortec heads? If not why? Is there already a thread that explains all of this? Sorry in advance.

[muscletrucks]

Thats a good question!!

[chevybill]

Vortec engines require a manifold specifically for vortec's, relating to how the intake bolts on to the heads. I think you can use vortec heads on an old style block, but not 100% sure. Vortec engines use electronic fuel pumps and have no provision in the block for a traditional fuel pump.

[Camper Power]

wat is the difference between a regular chevy engine and a vortech engine anyway?

[retselgerg]

The Vortec Head can be bolted on to any old school block however a special intake is required to allow a carb but also have the vortec bolt pattern GM offers one and so does summit but are offered in alum only....the Vortec head has a 64cc Combustion chamber and swirl ports which allows them to flow much better then the best old school chevy heads including the 202 heads, i have not used them but have friends that do and i can tell you this they are the best bang for your buck head on the market,

[cameeks]

Where the intake bolts to the heads it is at a wider pitch then the regular intakes

[muscletrucks]

Awesome info, thanks

[BP68]

I have a 89 Suburban long block I am using, and I swapped on Vortec heads, using GM head bolts for a Vortec motor, along with GM gaskets and an Edelbrock votec pattern intake with a 650 carb.

Vortec blocks also have a roller camshaft fyi. The roller cam and head design are the main diffs. Also have a 1 peice main seal. They also use a platic timming cover, but I believe a early style metal cover will also work.

[67_C-30]

Originally Posted by cameeks

Where the intake bolts to the heads it is at a wider pitch then the regular intakes

They are also drilled at different angle. One thing to keep if mind if building a hot engine with Vortec heads that if you use a camshaft with more than .480" lift, the stock springs will coil bind. .488" is actually the dimensional limit, but with variances in tolerances, .480" lift is really pushing it. Most street profiles are no where near that lift, but keep it in mind if you building a street/strip engine with a radical cam. Here is a flow test comparing the Vortecs to old double humps (462's)are some aftermarket performance heads. They flow better up to .500" lift than any head in the test. They are capable of some very good HP numbers.

[retselgerg]

good info!! considering them for a later 383 IROC-Z Project

[67_C-30]

Originally Posted by retselgerg

good info!! considering them for a later 383 IROC-Z Project

They work great on 383's. I ran a set for a while on my 82 Z28, before I stepped up to 230cc Dart Iron Eagles. I forget to mention that reason they bind is that the valve guide boss is high on these heads and it has to be machined to run a bigger cam cam than .480 which is an easy job for any automotive machine shop. I was running 12.40's @ 109 MPH with the Vortecs and a fairly mild hyd roller on a 9.3 : 1 CR 383 with a 650 Demon carb, TH350 with a 2400 stall and 3.73 gears in my '82 Z28 before I got more racdical with 383.

[kohler]

gm also made an intake for a tbi set up for the vortex engine,i put one on my truck works great

[TonyJohnson]

A good number of the vortec engines have roller cams, as well.

[MrGoodpliers]

Vortecs are a great value. I bought a new set from a dealer for $399, and another set at a salvage yard for $200. They have heart shaped combstion chambers and redesigned ports which make for a much better flowing head than the general's previous designs. If you use factory gaskets, be aware that they are only torqued to something like 15lb-ft and will fail if you overtorque them. I like the fel pro gaskets as the match the ports a little better. Self-aligning rocker arms are also required.

[FormerMember]

Originally Posted by BP68

They also use a platic timming cover, but I believe a early style metal cover will also work.

Yes, you have to pull the collar off to get it to fit.



That is a 99 5.7L Vortec. With an old school timing cover on it. You also lose two bolts in the cover, as the block's not tapped for it. It's also running a GM performance intake for TBI. They (GMPP and Edelbrock each), make an intake for TBI or Carb.

96-99 is the cross over years, where some parts will work. We happened to add a 400 crank to make this one a 383. Also got some head work to the Vortec heads.

The later model Vortecs get much different, with coil packs instead of distributors and a bunch of whole other fun items.

[Billla]

So let's make this a FAQ. There are 3 types of aftermarket Vortec heads as below. The Vortec design has increased "swirl" for improved combustion and flow that's equal to or better than entry-level aftermarket heads - especially in the mid-range which is so important for a street engine.

[EDIT based on 67_C-30's comments]

• Stock Vortec P/N 12558060; 170cc intake runner, 1.94/1.5 valves, requires Vortec intake, .475 max lift (upgraded heads available from SDPC and Summit). Springs are P/N 10212811 ("Z28"). Good for engines making up to about 1.2 HP/CID. Sell for about $300 each, assembled.
• Small-port Bowtie P/N 25534421; 185cc intake runner, 2.00/1.55 valves, uses either Vortec or GEN I intake, .530 max lift. Springs are P/N 12551483 (LT4). Good for street engines making above 1.2 HP/CID but less than 1.4. Sell for about $500 each, assembled.
• Large-port Bowtie P/N: 25534446; 225cc intake runner, 2.00/1.55 valves, uses either Vortec or GEN I intake, .530 max lift. Springs are P/N 12551483 (LT4) Good for engines making up to about 1.5 HP/CID or more. Sell for about $650 each, assembled.

[67_C-30]

Originally Posted by Billla

So let's make this a FAQ. There are 3 types of aftermarket Vortec heads as below. The Vortec design has increased "swirl" for improved combustion and flow that's equal to or better than entry-level aftermarket heads - especially in the mid-range which is so important for a street engine.

• Stock Vortec P/N 12558060; 170cc intake runner, 1.94/1.5 valves, requires Vortec intake, .475 max lift (upgraded heads available from SDPC and Summit). Springs are P/N 10212811 ("Z28"). Good for engines making up to about 1 HP/CID. Sell for about $300 each, assembled.
• Small-port Bowtie P/N 25534421; 185cc intake runner, 2.00/1.55 valves, uses either Vortec or GEN I intake, .530 max lift. Springs are P/N 12551483 (LT4). Good for street engines making up to about 1.2 HP/CID. Sell for about $500 each, assembled.
• Large-port Bowtie P/N: 25534446; 225cc intake runner, 2.00/1.55 valves, uses either Vortec or GEN I intake, .530 max lift. Springs are P/N 12551483 (LT4) Good for engines making 1.2 HP/CID or more. Sell for about $650 each, assembled.

Pretty good list except the HP/CID numbers are off. Stock Vortecs are capable of producing 420+ on 350CID engine which is exactly 1.2 HP/CID. This has been documented buy numerous magazine buildups, and I have done it myself on two different occasions.

[FormerMember]

Originally Posted by 67_C-30

Pretty good list except the HP/CID numbers are off. Stock Vortecs are capable of producing 420+ on 350CID engine which is exactly 1.2 HP/CID. This has been documented buy numerous magazine buildups, and I have done it myself on two different occasions.

Agreed. The motor in that Blazer dyno'd at 413 hp and 453t lbs of torque. We could've squeezed more out of it, but elected to keep it a bit tamer. Granted, it's a 383 with port and polish work, but stock GM castings, but does prove to be more than 1HP per CI.

[Billla]

Originally Posted by 67_C-30

Pretty good list except the HP/CID numbers are off. Stock Vortecs are capable of producing 420+ on 350CID engine which is exactly 1.2 HP/CID. This has been documented buy numerous magazine buildups, and I have done it myself on two different occasions.

I'm interested in the magazine builds and your dyno results showing this power level on STOCK Vortecs. The flow tops out around .500 lift at 225/149. which isn't consistent with that power level in my experience. Even if those power levels are seen, the stock Vortecs would definitely be holding the engine back.

Again, all IMHO. I've built 6 engines now with the stock Vortecs and love 'em - but I don't recommend them for power levels much over what I noted. Willing to edit my post with some add'l background

[67_C-30]

These are the only two I can find on online but I have several more here in mags from 5 -6 years ago that were in Super Chevy and Car Craft. Forget dyno bumbers, I had a set of STOCK Vortec heads on a .030" over 4 valve relief hypereutectic flattop 350, with COMP .474" lift 284/288 duration hyd roller with a Edelbrock Performer PRM intake, a 650 Demon carb with a TH350, 2400 B&M Holeshot stall and 3.73 gears in a 3360# (race weight) '82 Z28 and I ran 12.40's at 109. You do the math. According to NHRA's formula, it takes at 340 RWHP to push a 3360# car to 109 MPH trap speed. Figure the 20% drivetrain that is typical with an automatic transmisson, and the puts you at 425 HP at the crank. Either way you slice it, that is way above 1HP/CID.

The tests and literature I've seen show that the Vortecs flow around 240 cfm at .500". The chart above shows 239/147.



http://www.popularhotrodding.com/eng...ine/index.html

http://www.chevyhiperformance.com/te...ild/index.html

[BurnoutNova]

another common misconception ive seen often, alot of people mistake the 87- and up centerbolt style head for the vortech heads. ive seen this so many times i dont even try and correct people. the vortechs have the 3 little triangles on the front, and the older 80's centerbolt vc style head doesnt

[FormerMember]

Originally Posted by BurnoutNova

another common misconception ive seen often, alot of people mistake the 87- and up centerbolt style head for the vortech heads. ive seen this so many times i dont even try and correct people. the vortechs have the 3 little triangles on the front, and the older 80's centerbolt vc style head doesnt

96-99 only.

[67_C-30]

Originally Posted by BurnoutNova

another common misconception ive seen often, alot of people mistake the 87- and up centerbolt style head for the vortech heads. ive seen this so many times i dont even try and correct people. the vortechs have the 3 little triangles on the front, and the older 80's centerbolt vc style head doesnt

Yeah, and the ironic part is that they are even termed as a swirl port head as well, except its the intake port that is being referred to. They are almost half a port if shine a flashlight in there. There is a flow divertor cast in the center of the port in line with valve guide boss that directs the flow to create turbulance. As far as performance, they are truly the worst SBC you could use.

We used to joke around because the 305 TBI heads are casting number 187, which in police code Homicide/DOA!!

[Billla]

Our numbers might differ by a bit, but I'll buy the 1/4 mile numbers (the only real numbers, I agree) and I definitely trust the Popular Hot Rodding guys...CHP, not so much.

So I'll tweak my post - I still think that at these power levels you'd find more power with an aftermarket head than the stock Vortecs...which was the point of my comment - but it's a fair cop I have a tendency to go a bit mild on my cam choices, which is part of the difference. Comment on the tweak and I'll adjust a bit more if needed.

All the stock Vortec flow numbers I've seen have been around the numbers i noted - the small-port Bowtie number are closer to what you note. We might have to agree to disagree on that one

[67_C-30]

I think the revised numbers are basically the max capabilities of each head, and you and I both know not every builder is going to acheive those numbers. You're going to have those guys out there that going to run a flattop pistons in the 9.5 - 9.6 CR range, a camshaft that fits within the .480 lift max window, but he's going to put a single plane Strip Dominator or Victor Intake with 850 Demon or HP with 1 3/4 headers and chunk it in a car with a 3500 RPM convertor and 4.56 gears! Then he'll bash the Vortecs because he has a 1500 RPM power range with small cam and huge convertor. Then you also have the guy that will have the Vortecs machined, and put the biggest cam, intake, carb and headers he can afford and put it in a 3800# Chevelle with a stock or 2000 RPM convertor with 3.08 geared open diff rearend. The combination of parts is the most important (and often most overlooked) aspect of performance engine building.