Vortec Heads... Is the Torque Curve That Much Better??

[Guest Mike]

I'm working on my Gen1 SBC 350 and, since I'll be pulling the heads anyway, I may swap them. The existing heads are unmodified aluminum Edelbrock Performer RPMs. I'd like to increase and broaden the torque curve. I want this engine to pull hard all the way to 6K RPM.

 

I realize there are other discussions regarding Vortec heads, but I want a straightforward answer with facts. Anyone who has experience designing and building Gen1 SBCs with both styles of heads please chime in.

 

QUESTIONS: Are the Vortec heads really that much better in that regard? I'll probably go with iron due to cost. This increases my engine weight approximately 40 pounds. Is the weight gain completely offseting my power gain? Regarding added weight... I realize handling will be affected a bit, but that's of secondary concern.

 

THANKS!!

[280zwitha383]

I'm a pretty big advocate of vortec heads and not so much on the edelbrock performer heads. However, I wouldn't ditch the aluminum aftermarket heads for stock production iron heads. I don't think you will come out on top.

[Guest Mike]

I'm a pretty big advocate of vortec heads and not so much on the edelbrock performer heads. However, I wouldn't ditch the aluminum aftermarket heads for stock production iron heads. I don't think you will come out on top.

 

I was thinking about some nice aftermarket iron Vortec heads. Some supposedly very good ones are available for a few hundred bucks... $600 or so per pair assemble.

[grumpyvette]

the originasl vortec haeds are designed for max TORQUE in the 3500rpm area on a 350 displacement, they flow much better than a few stock, cast heads but there NOT PERFORMANCE HEADS

 

http://www.chevyhiperformance.com/techarticles/148_0506_gm_bow_tie_vortec_small_block_engine/photos.html

 

 

chevy has just announced NEW versions of the vortec heads which are designed for increased flow and are similar to the FASTBURN heads but the new vortec 206cc heads are CAST IRON with a 64cc chamber

PART # 25534371 bare# 25534431 assembled

theres also a slightly improved 175cc version part# 25534351

 

read this

 

http://chevyhiperformance.com/techarticles/148_0506_thunder/

 

these new heads are drilled and tapped for both old and new valve cover and both old and vortec style intakes, they have 2.00 intake and 1.55 exhaust valves and 65cc chambers

GM has also released a new 383 425hp crate engine part # `12498772

 

 

25534431 Vortec Bow-Tie Large Port Cylinder Head, Complete

GM Performance Parts' latest and most powerful iron cylinder head with "Large Port" for Street or Racing. This Vortec design Special Performance cast iron cylinder head features revised intake and exhaust ports and includes 2.00" hollow stem intake valve P/N 12555331 and 1.55" sodium filled exhaust valves P/N 12551313. The deck surface is .450" with 65 cc combustion chambers, 206 cc intake and 77 cc exhaust ports. All Vortec intake ports are taller and narrower than early model Chevrolet heads. The valve cover mounting holes are for both early model flange and late model center. This head also includes intake manifold mounting holes for both early model 6 bolt main and late model 4 bolt Vortec design. The head has screw in rocker studs P/N 12552126, large valve spring pocket machining, and will accept up to .530" lift camshafts without modifications. Heads are identified with the Bow-Tie logo on the exterior of the head below exhaust flange and Vortec logo on top of intake port area. They also feature GM logo cast into bottom of intake ports. Includes valve spring P/N 12551483, valve seal P/N 10212810, and spring cap P/N 10212808.

Technical Note: You must use a raised runner design intake mainifold P/N 10051103 (6 bolt mounting), or Vortec design 12366573, 12496820, 12496821, 12496822, and 12499371 (4 bolt mounting) with this head. You can use production Vortec intake gaskets P/N 12529094 (torque spec. 11 ft-lb/ 15Nm) for mounting Vortec design heads or use P/N 12497760 (torque spec. 30 ft-lb) with conventional material when using on early model raised runner or Vortec design intake manifolds, this gasket has both 6 bolt and 4 bolt Vortec attaching holes. Head casting P/N 25534371C.

[grumpyvette]

http://www.rustpuppy.org (goodwrench quest)

 

might also help you get a good grasp on the diffferance in potential

[Guest Mike]

www.rustpuppy.org (goodwrench quest)

 

might also help you get a good grasp on the diffferance in potential

 

 

Thanks for the info, Grumpy. I'll have to keep this within my budget so custom machining is not in the equation. I need to find really good aftermarket heads for $1K or so... and only then if there is a significant difference between them and my current Performer RPM heads. Smoothing out and extending the torque curve is important to me.

 

You mentioned GM's new 206cc iron Vortec heads... will these show me a marked improvement below 6K RPM or am I better off waiting until I can build a better motor capable of 7-8K RPM redline? I really want this motor to pull hard from 1.5-6K RPM but I'm afraid to push it further... I'm assuming the existng lower-end is fairly stock on this engine.

[dr_hunt]

I think the trick flow heads are in the 1K price range. I managed to pick up a used set of AFR 227 fully cnc competition heads for 1K. But IMO, buying new ones for about 1350 is a good deal too! Nothing like good head, I mean heads.

[grumpyvette]

http://www.kendrick-auto.com/edelbrock_performer_rpm_cs.htm

 

http://www.kendrick-auto.com/vortec_cs_gm_head.htm

 

you won,t gain a thing going to standard vortecs over the rpm heads, thats wasted money,but Id need to know more about your current combo to know where your best areas are and where the worst potential lies, or to know where your restricted, those heads may not be great but they are certainly adequate for a mild build, the compression,cam timing, rear gear,converter and exhaust, ETC.,ETC, are all suspect at this point, please post your combo

 

"I'd like to increase and broaden the torque curve. I want this engine to pull hard all the way to 6K RPM."

 

doing thats not hard, and making good power doing its not too hard, but youll need to carefully match components, now I don,t know what your drive train consists of, but if your going to rebuild that 350, Id strongly suggest you start looking into a 383 10.5:1 cpr stroker assembly and a good solid lifter cam, as you can make a very impressive engine that way, provided you think things thru before jumping in with both feet

[grumpyvette]

http://www.ryanscarpage.50megs.com/combos1.html

 

notice that it takes BOTH good heads and a decent cam to pull decent hp/tq numbers and that its far easier with a larger displacement and higher cpr

[Guest Mike]

I think the trick flow heads are in the 1K price range. I managed to pick up a used set of AFR 227 fully cnc competition heads for 1K. But IMO, buying new ones for about 1350 is a good deal too! Nothing like good head, I mean heads.

 

Yup... I know the engine must pump air to make power. The dynamics are beyond my current understanding though. I guess I could swing $1350 to score some good head(s) but it would be hard-on my budget.

[Guest Mike]

http://www.ryanscarpage.50megs.com/combos1.html

 

notice that it takes BOTH good heads and a decent cam to pull decent hp/tq numbers and that its far easier with a larger displacement and higher cpr

 

Thanks for the link, Grumpy. I'll study those combos carefully. A roller cam with LS1 firing order is another upgrade. A new induction system with either dual 4bbl (small ones) or triple 2bbl is another. Of course new headers and exhaust with X-pipe follow. I'll match everything the best I can.

 

I've considered a BB Chevy too... but I'd like to get the SBC running well instead. Hopefully this will be cheaper and satisfy my need for speed. I'd really like a bored and stroked LS6 but that's just not in my near future... too much $$$. If the SBC is a lost cause, I may just go for a mild 454 with forged internals and throw a little nitrous at it. I hate to add that much weight to the car, especially up front, but I really need to keep my costs down.

[grumpyvette]

I can give you a realitively cheap and simple combo, but if you don,t follow it almost exactly (which some guys don,t) it won,t work correctly...and youll need to be truthful about what your looking for and be willing to put up with a few facts, and one is that it ALWAYS COSTS MORE THAN YOU THINK,and IF it runs great at 6000rpm and can scare the hell out of you, accelleration wise,chances are excellent that it runs like crap at 1000-1500rpm in traffic

and getting the rear gear ratio and stall speed correct is almost as important as the cam,cpr and heads used...you CAN,T just swap parts you got at a good DEAL price, parts must match,sure you can get a smokin deal on some parts, but they are almost worthless if they don,t match the intended application

[jt1]

I think the heads you've got are better than the vortecs, and a switch would be a mistake. Use the rpm's with a performer rpm or rpm air gap intake, a Holley 600 double pumper, good ignition, a cam in the 220-225@50 range, 1 5/8 headers with a Xpipe or hpipe, and get the DCR to about 8.5.

 

Most importantly, spend a day on a dyno with a wideband to get the combo tuned for power and throttle response. Proper tuning will pay huge dividends.

 

John

[COZY Z COLE]

I can give you a realitively cheap and simple combo' date=' but if you don,t follow it almost exactly (which some guys don,t) it won,t work correctly...and youll need to be truthful about what your looking for and be willing to put up with a few facts, and one is that it ALWAYS COSTS MORE THAN YOU THINK,and IF it runs great at 6000rpm and can scare the hell out of you, accelleration wise,chances are excellent that it runs like crap at 1000-1500rpm in traffic

and getting the rear gear ratio and stall speed correct is almost as important as the cam,cpr and heads used...you CAN,T just swap parts you got at a good DEAL price, parts must match,sure you can get a smokin deal on some parts, but they are almost worthless if they don,t match the intended application[/quote']

 

I agree 100 per cent with this statement...

 

 

LARRY

[Guest Mike]

I can give you a realitively cheap and simple combo' date=' but if you don,t follow it almost exactly (which some guys don,t) it won,t work correctly...and youll need to be truthful about what your looking for and be willing to put up with a few facts, and one is that it ALWAYS COSTS MORE THAN YOU THINK,and IF it runs great at 6000rpm and can scare the hell out of you, accelleration wise,chances are excellent that it runs like crap at 1000-1500rpm in traffic

and getting the rear gear ratio and stall speed correct is almost as important as the cam,cpr and heads used...you CAN,T just swap parts you got at a good DEAL price, parts must match,sure you can get a smokin deal on some parts, but they are almost worthless if they don,t match the intended application[/quote']

 

I'm all ears, Grumpy!! If you're willing to help, I'm definitely happy to listen. I'm not afraid to put some $$$ into this, but I must be very careful on my budget.

 

I suspect my definition of "fast" is much tamer than yours. I bought this Alpha 1 GTO for the looks and straight speed potential. This isn't a track car so high-speed cornering is a far 4th to straight speed, looks... and "reasonable" fuel mileage.

 

GOALS:

drivable in stop-&-go traffic

cruise easily downtown & on the highway

skunk most other performance cars on the road...

(...especially modified Mustangs)

"reasonable" fuel mileage

11's in the quarter mile

160+ top speed

 

UPGRADES WANTED:

2x4 or 3x2 (preferred) carbs

roller cam (LS1 firing order)

roller rockers

roller timing chain (or belt)

better headers (SS/ceramic)

better exhaust & X-pipe (all SS preferred)

better heads (Vortec?)

new dizzy and ignition (MSD, Crane, Mallory, Holley???)

progressive nitrous (50HP in 2nd, 100HP in 3/4)

hi-po electric fuel pump and regulator

suspension lowering springs (adjustable?)

frame mods (front-to-rear rails, tower cross-braces, roll bar, other?)

update from Scarab to JTR kit

200R4 transmission with 2K stall converter

wider rear tires (GTO style) for traction and authentic looks

other...???

 

THANKS!!!

[grumpyvette]

I'm all ears' date=' Grumpy!! If you're willing to help, I'm definitely happy to listen. I'm not afraid to put some $$$ into this, but I must be very careful on my budget.

 

 

 

 

[b']GOALS:[/b]

drivable in stop-&-go traffic

cruise easily downtown & on the highway

skunk most other performance cars on the road...

(...especially modified Mustangs)

"reasonable" fuel mileage

11's in the quarter mile

160+ top speed

 

UPGRADES WANTED:

2x4 or 3x2 (preferred) carbs

roller cam (LS1 firing order)

roller rockers

roller timing chain (or belt)

better headers (SS/ceramic)

better exhaust & X-pipe (all SS preferred)

better heads (Vortec?)

new dizzy and ignition (MSD, Crane, Mallory, Holley???)

progressive nitrous (50HP in 2nd, 100HP in 3/4)

hi-po electric fuel pump and regulator

suspension lowering springs (adjustable?)

frame mods (front-to-rear rails, tower cross-braces, roll bar, other?)

update from Scarab to JTR kit

200R4 transmission with 2K stall converter

wider rear tires (GTO style) for traction and authentic looks

other...???

 

THANKS!!!

 

ok heres where REALITY steps on your dream world...many of your stated requirements are somewhat contradictory, like your very unlikely to get these goals without very expensive parts(turbo,supercharger,dirrect port nitrous injection,etc)

and you need the higher stall converter and better heads, larger displacement, etc, if your serious about reaching deep in the 11 second range and reaching 160mph, both goals require power levels your unlikely to reach with a 2000rpm stall speed and a truely traffic friendly engine combo. you could build that 383 and build it with good quality parts for about $6000-$7000 starting from scratch. (less if your willing to shop hard and do your own assembly), but the other combo would EASILY run TWICE as much, and youve still got the suspension,brakes,coolant,roll cage,tires,ETC after thats done....

GOALS:

drivable in stop-&-go traffic

cruise easily downtown & on the highway

skunk most other performance cars on the road...

(...especially modified Mustangs)

"reasonable" fuel mileage

11's in the quarter mile

160+ top speed

yes all those goals COULD be met...but it would require a VERY EXPENSIVE combo of parts and since your very obviously on a fairly limited budget (LIKE MOST OF US ARE!) Id strongly suggest just building a responsive 383 that makes good power, in the 450-500hp plus range, like I posted on the other thread

 

 

http://airflowresearch.com/eliminator.php[/url]

Engine Specs:

 

 

383 CID

9.6 : 1 CR ...boost to 10.5:1

Edelbrock RPM Air Gap Intake

Comp 236/242 Hydrolic Roller Cam swap to the crane 114681 solid flat tappet cam/lifters

Holley 750 Carb

1.75 Long Tube Headers

MSD Ignition

38° advance with original 195's

37° advance with Eliminator 195's

Penzoil 15w-40

93 octane Amoco pump fuel

 

http://www.newcovenant.com/speedcrafter/calculators/intake.htm

 

http://www.bgsoflex.com/intakeln.html

 

http://www.newcovenant.com/speedcrafter/calculators/runnerarea.htm

 

http://www.engr.colostate.edu/~allan/fluids/page7/PipeLength/pipe.html

 

to cut cost significantly, swap to a 10.5:1 cpr and a crane 114681 flat tappet cam

 

http://www.cranecams.com/?show=browseParts&action=partSpec&partNumber=114681&lvl=2&prt=5

 

and use 1.6 roller rockers, CHECK ALL CLEARANCES TWICE...MAKE THAT FOUR TIMES ..CAREFULLY

 

 

youll want a 3.73:1-4.11:1 rear gear and a MANUAL trans or a 3000rpm stall converter....yeah your correct if your thinking the engine will lope and lack some power under about 2500rpm, but hold on tight after that rpm till well in excess of 6000rpm

if you want slightly more lope and are willing to accept a roughter idle and want more low rpm torque, you can have almost the same cam on a tighter LCA

http://www.cranecams.com/?show=browseParts&action=partSpec&partNumber=110921&lvl=2&prt=5

 

either cam choice will make close too/more than 500 hp easily, depending on how the engines built

 

you could also go the cheap route, install a set of 10.5:1 pistons AND A 3.75" STROKE CRANK in your current 350 block, BUILD A 383 WITH A STROKER CRANK ASSEMBLY and install a slightly milder cam, LIKE A crower #00320

 

http://www.crower.com/misc/cam_spec/cam_finder.php?part_num=00320&x=14&y=12

 

 

 

AND YOUR CURRENT HEADS youll spend far less than $2000-$2500 ON THE ENGINE AND GET TO ABOUT 380-400HP, BUT A 3.73:1 REAR GEAR AND A 3000 STALL CONVERTER IS ADVISED STRONGLY AS IS A GOOD LOW RESTRICTION EXHAUST

YOULL PROBABLY RUN 12S BUT AT 1/4-1/2 THE COST AND FAR LESS WORK TAN THE OTHER OPTIONS

[Guest Mike]

ok heres where REALITY steps on your dream world...

 

All great info, Grumpy. Thank you!!

 

I'm trying to keep this 355 shortblock and work around it... to save $$$. What if I give you a couple of more realistic figures... 140MPH top speed and mid 12's in the quarter mile? I still want the 3x2 or 2x4 carbs... if that's feasible. I just want the best performance I can afford and it must be streetable.

[grumpyvette]

DUAL 4 BARREL CARBS LOOK GOOD, SOUND GOOD AND WILL PERFORM WELL, BUT THIER PERFORMANCE ADVANTAGE IS SLIGHT TO zip or NON,EXISTANT, compared to a well set up 4 barrel/intake , they won,t get as good gas mileage and they are far harder to tune correctly,personally I love dual quads, but they are far from ideal at $3 a gallon for gas

 

http://store.summitracing.com/partdetail.asp?part=SUM%2DCEDL300&N=700+4294845683+115&autoview=sku

 

(BTW the picture at summits generic not a chevy intake)

think it thru, dual quads are neat looking but will cost more and if your not into tunning they can be a bitch to get correctly set up,(I personally love them, but most guys can,t tune/adjust for $%^^&

 

if your going to get good performance rom that 350 youll need higher compression pistons,and a matched cam, by the time you reballance, re-ring, and put new bearings into that 350 the cost differance, upgrading to a longer stroke crank to build a 383, (ESPECIALLY ONCE THE ADDVANTAGE OF LARGER DISPLACEMENT) is figgured in is only going to be a few hundred at MOST MORE,ID sure build a 383

[jt1]

posted by Mike

 

I just want the best performance I can afford

 

You probably need to define your budget and what parts you've got on hand, and go from there.

 

Your goals require a high strung street engine, close to a race engine, and it ain't gonna be cheap. It's also probably out of the range of vortecs, and I don't think anybody makes multi carb intakes for vortecs.

 

John

[Guest Mike]

DUAL 4 BARREL CARBS LOOK GOOD' date=' SOUND GOOD AND WILL PERFORM WELL, BUT THIER PERFORMANCE ADVANTAGE IS SLIGHT TO zip or NON,EXISTANT, compared to a well set up 4 barrel/intake , they won,t get as good gas mileage and they are far harder to tune correctly,personally I love dual quads, but they are far from ideal at $3 a gallon for gas

 

http://store.summitracing.com/partdetail.asp?part=SUM%2DCEDL300&N=700+4294845683+115&autoview=sku

 

Yeah, that's true about 2x4 setups. But I want a more agressive look to this car. My preference is really a 3x2 setup. I hear that a well-designed triple deuce with progressive linkage makes for very good gas mileage and performance. The original 250 GTO had three dual-throat Webers and a long oval breather. I can't afford Webers, but three Holleys would look/perform well, I think:D Could a 3x2 setup be worked into your design? Maybe something similar to the SBC setup at VintageSpeed dot com?