230-cfm
He took a set of Vortec right out of the box and clamped them down to his Superflow bench. With 230-cfm max flow, these heads are actually pretty good, except when you notice that peak flow is at .
How do I get more valve lifts?
Every little bit counts when it comes to performance and an excellent way to squeeze some extra power out of your engine is by increasing your rocker arm ratio. For example, moving from a 1.5 ratio rocker arm to a 1.6 would effectively increase the overall valve lift.
Are L31 Vortec heads good?
Chevrolet Performance Parts L31 Vortec Cylinder Cast Iron Heads have set the standard for proven performance and budget spending . The best out-of-the-box head for the money! Excellent flow produces broad torque and killer power. Stock springs are good up to 0.450″ lift.
Is it worth porting Vortec heads?
The Vortec heads offer great intake port flow despite the rather small 1.94-inch valves. This is often called pocket porting and the area just below the 45-degree valve seat is where you can gain the greatest airflow improvement for the least amount of effort.
How much horsepower do Vortec heads add?
Most of these small block Chevy heads offer a power increase of around 40 hp, and even the iron Vortec heads were worth 20 hp over stock. The two best small block Chevy heads in terms of peak horsepower were worth more than 60 hp.
How much lift can stock Vortec heads handle?
The factory Vortec heads use a light, single-wire valvespring with a damper that generates between 70 and 80 pounds of load on the seat. Because these heads are meant to work with a 1.5:1 rocker, their tall valve guides can only handle maximum valve lifts of around 0.420 inch.
How much lift do 1.6 Rockers add?
With a 1.6:1 rocker, this gives us 0.508-inch valve lift at max lift, an increase of 0.031 inch. It doesn’t sound like much, yet it was enough to show a sizeable gain, mainly because it increases the amount of time that the valves are open at higher lifts, allowing more air to flow through the heads.
Are Vortec heads aluminum?
Aluminum cylinder heads are standard on the ZZ4 and feature 58cc chambers, 1.94-inch intake valves, and 1.50-inch exhaust valves. The heads that were tested included the two versions of the Vortec Bow-Tie, as well as the GM’s Vortec truck head, Fast Burn aluminum head, and the stock aluminum ZZ4 production head.
Can I install a high-lift camshaft with a Vortec head?
Installing a high-lift camshaft in conjunction with the Vortec cylinder head requires several minor modifications. Increased valve lifts require stronger springs. Comp Cams recommends that its PN 986 double valvespring be used with its XE 282HR camshaft.
What’s the difference between undercut and Vortec heads?
Vortec heads (and most others) like straight stemmed valves. Undercut valves create unwanted turbulence and a decrease in intake charge velocity (they add volume (slowing the gases) to the overall “port” volume just behind the valve where max velocity is required.) Generally speaking, Vortec’s stall at between .500” and .550” valve lift.
Are vortec heads good for performance?
The cast-iron Vortec heads offer a 170cc LT1-derived port, making them great performance pieces for street engines when tons of torque is key. As the displacement of the engine increases, the torque numbers go through the roof and the horsepower figures follow.
How much power does a Vortec head add to a 383?
CHP recently bolted a pair of Vortec heads on a 383ci (see “Twister, Part III” on page 96) and made 486 lb-ft of torque at 4,600 rpm and 449 hp at 5,300 rpm. These power levels were achieved using a stock iron Vortec cylinder head featuring 64cc combustion chambers and 1.94-/1.50-inch intake/exhaust valves.
