I am rebuilding my 327 for my 68. I was thinking about getting a set of new 2.02 heads? I am going to have 10-1 compression and a good cam also having the engine balanced. Looking for 400 horsepower.

HP tip. Take the intake valve max lift, say, .500 at the valve, and check the flow of the head (intake side) at that lift and double that number and thats the max hp that head will make.
Looks like this .500 lift and 210cfm@.500 lift equals 420 max hp from that head. Airflow equals hp which is why head porting is part black art and part science.
George

Probably won't make too much difference. If you were building a maximum effort racing engine with higher compression and a cam that makes power at 5500 rpm plus then the 2.02 heads would be essential. More important than valve size is how good does the head flow. Vortec heads will outflow every early factory performance head with 2.02 intake valves but they all have 1.94 valves.

I was told that the new Vortec heads would be the way to go. Thanks guys, going to get some Vorec heads.

I was told that the new Vortec heads would be the way to go. Thanks guys, going to get some Vorec heads. I'd get a set of World Product Dart 2 Sportsman heads befor Vortec !!!!!!

Can you tell us why?

Can you tell us why? Dyno tests have shown better HP and torque with the Dart 2 Sportsman heads then with Vortecs.

Ok.

How much money do the Dart 2 Sportsman heads cost. How much horsepower would I be looking at. 327 with Comp cams Xtreme Energy, 10 to one compression and headers. I was lookin for 325 hp or more.

http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=2442&prmenbr=361955-011250-2 64cc, Straight Plug-Complete (Each) Applications: World has tested Sportsman-II heads in many applications including 375Hp 9:1 street engines; 450HP 9.8:1 street /strip engines; all the way to 940HP blown alcohol drag race engines.
Typical Application Street: 274 Cam: 230/236° .487''/.490'', Dart II Sportsman #955-061010 dual plane intake; 750 cfm carb, 1-3/4'' header. 430HP on 9.8:1 355; 480HP on 383 10.5:1 (varies with displacement and compression ratio).
Typical Application Drag Race: Modified 750 cfm carb, 276/284° roller cam, single plane plenum intake, 1-3/4''-plus header. MUST Upgrade to 1.550'' roller valve springs and 10° hardware. Up to 650HP normally aspirated depending on displacement and CR and porting.

TECHNICAL SPECIFICATIONS

Material: High density cast iron
Valve Seats: Integral intake,hardened steel exhaust
Valve Guides: Integral cast iron
Valve Spring Seats: Machined for 1.250'' springs
Valve Size: 2.020'' x 1.600''
Rocker Arm Studs: 3/8'' shank, screw-in style with hex shoulder furnished with assembly
Exhaust Flange: Stock locations, 7-bolt universal pattern

Included In Assembly: Manley Street Flo stainless steel valves (1-piece forged, with undercut stems and swirl-polished heads), ring & band style valve seals, 1.250'' valve springs, Manley 7° chrome moly retainers, keepersand pushrod guide plates.

Recommended Installation Items:

Head Gaskets: Fel-Pro #1003 ( 265-350 ) or equivalent
Puhshrods: Requires heat-treated pushrods. Use of 1.6 ratio rocker arms require elongation of pushrod holes.
Spark Plugs: Accepts 14mm .460'' reach tapered seat 5/8'' hex (Champion #670 or #802) or equivalent
Intake Gasket: Fel-Pro #1205 or equivalent
Exhaust Gasket: Fel-Pro #1404 or equivalent

Machine Shop Specifications:
Maximum Valve Diameter: 2.100'' x 1.600'' or 2.080'' x 1.625''
Maximum Spring Seat Depth (from inside step): .030''
Maximum Spring Diameter: 1.550''
Approximate Milling Guidelines(varies with depth): .0065'' per cc
Maximum Flat Mill Depth (up to intake seats): .040''
Maximum Angle Mill ( approx. 50-52cc volume): .175'' depth

NOTE:These specifications are for reference only. ALWAYS measure before machining.

Look, there's no doubt that those World heads are a great high performance piece and no doubt they would outperform Vortec heads but you could buy a pair of Vortec heads for the price of one World head and still have left over change. For a 100% effort the World heads are an excellent choice but for less than a 100% effort the Vortec heads are one heck of a deal.

Look, there's no doubt that those World heads are a great high performance piece and no doubt they would outperform Vortec heads but you could buy a pair of Vortec heads for the price of one World head and still have left over change. For a 100% effort the World heads are an excellent choice but for less than a 100% effort the Vortec heads are one heck of a deal. I agree they are spendy, but in my honest opinion, they're worth it. I've ran them on meny street vehicles, and have always been happy. Correct me if I'm wrong, but don't Vortecs have a different bolt pattern for the intake manifold ??? And I thought I heard that you're limited on cams because of valve springs. I'm no expert, so I could be wrong.

There are specific Vortec head intake manifolds and they are not pricey. The Vortec intake manifold is more efficient than the standard SB Chevy intake manifold. If you need a camshaft with a lift in excess of .480" the heads have to be modified. But the point remains that not everyone needs those World heads and you can easily get 350--400hp out of box stock Vortec heads. From PACE (http://www.paceparts.com/store.asp) you can get a complete kit with a new intake manifold, new rocker arms, all the gaskets, and two new assembled heads for less than $800. You got the whole top half of the engine (less carb) for less than the cost of two World heads. On a cost effective basis that's impossible to beat.

There are specific Vortec head intake manifolds and they are not pricey. The Vortec intake manifold is more efficient than the standard SB Chevy intake manifold. If you need a camshaft with a lift in excess of .480" the heads have to be modified. But the point remains that not everyone needs those World heads and you can easily get 350--400hp out of box stock Vortec heads. From PACE (http://www.paceparts.com/store.asp) you can get a complete kit with a new intake manifold, new rocker arms, all the gaskets, and two new assembled heads for less than $800. You got the whole top half of the engine (less carb) for less than the cost of two World heads. On a cost effective basis that's impossible to beat. So Vortec heads would need to be modified to run the Comp Cams 292-H Magnum cam ??? 292 dur. and 501 lift and 110 lobe sep. . I also plan on running the Dart "Kool can" intake manifold. http://www.ryanandmolly.com/ebay/koolcan.jpg But I do agree Vortec are cheaper. I myself tend to spend a little more then most people on parts, but I'm not no big rush to get a project done. I'll take alittle longer saving up for my parts so I can build it just the way I want it. It's pretty awsum hearing a monster cam like that at idel.

If you are going with such a large cam than you are leaving the realm of a usual street perrformance smallblock and you could use the extra breathing of the World heads. My comments on the Vortec heads applied to engines of less than 350-400hp potential.

If you are going with such a large cam than you are leaving the realm of a usual street perrformance smallblock. I've used that cam in quite a few street driven small block chevys. Some people think I'm nuts for running a cam that big on the streets, but I like it alot.

Vortec heads are awesome for what they're meant for, but not much beyond.

Their flow characteristics make them killer street heads, especially considering their cost.

You can make the 400 HP streetable with the Vortecs, but if you want more, you'll need to upgrade to Dart heads or something else. The Darts will be about half again the cost of the Vortec heads.

Another head you may want to consider if you're power hungry and have a little coin is the Brodix Track 1. This is an aluminum head which flows great and can be had for around $1500 for the pair, although I have seen them cheaper. I have seen dirt racers make upwards of 600 horses with these heads using pretty high compression and solid cams.

Regardless of what you get, having the heads milled and installing the 2.02/1.60 valves will give you more performance. However, I have heard that Vortecs don't respond to modification (i.e. bigger valves, porting) very much at all.