Vortec Head Modifications : 89 Pontiac Transam GTA - Vortec 350 TPI / All the parts are included and they sell for about $680 a pair.. Tbi to vortec head conversion gmc truck forum / vortec heads also use a different intake bolt angle than traditional sbc heads and, as mentioned previously, camshaft lift needs to be kept on the low side, unless other modifications are made. Are you looking to get almost 100 more horsepower from your gm 350 crate engine? Valve spring seat diameter is 1.280. Rocker arm studs can be pinned or drilled and tapped to 3/8. Starting in 1996, on several gm trucks and vans, the l31 vortec heads came on the scene.
So you can see, the oem tune really chokes the potential vs carb. The deck surface is.450 and features 65 cc combustion chambers, 175 cc intake and 65 cc exhaust ports. Camshafts with more than 0.475 lift require machining valve guide bosses and checking valve seal to valve spring retainer clearance. This vortec design special performance cast iron cylinder head features revised intake and exhaust ports and is machined for 2.00 intake valve and 1.55 exhaust valves. My cams gross lift is.559.
89 Pontiac Transam GTA - Vortec 350 TPI from members.optushome.com.au Truck pulls ok but lacking on long grades and really. The vortec 350 came in hundreds of thousands of chevrolet and gmc pickups, suvs, and vans from 1996 to about 1998, so they are easy to find and relatively inexpensive to build. The cam is based on the maximum lift for stock vortec heads and is a single pattern 215d/470l on a 112 center. Tony, just remember that total lift is the cam lobe lift and the rocker arm ratio for total lift. Two years ago we undertook an exhaustive (no pun intended) study of the vortec head in numerous modified states with different valve sizes, throat cuts, valve jobs, port mods, guide mods, etc. The real weakness of the vortec head is the exhaust port, a fact that is readily apparent when you get into porting these heads. 454 gen v vortec swap. Camshafts with more than 0.475 lift require machining valve guide bosses and checking valve seal to valve spring retainer clearance.
My cams gross lift is.559.
Can be machined for 2.020/1.600 valves. The l76 is a gen. Starting in 1996, on several gm trucks and vans, the l31 vortec heads came on the scene. Increased valve lifts require stronger springs. All the parts are included and they sell for about $680 a pair. Camshafts with more than 0.475 lift require machining valve guide bosses and checking valve seal to valve spring retainer clearance. I ported mine and fully worked the exhaust port (bowl work and contouring the runner). This is the speed secrets episode for you! Comp cams recommends that its pn. Truck pulls ok but lacking on long grades and really. Gm also sells vortec pattern intakes for tbi and 4bbl's. By changing the springs, the distance between the retainers and the valve seals hasn't changed. I will need to cut (reduce the height) of the valve guide boss.this is the curse (or part of the curse) of the vortec heads.
The vortec 350 came in hundreds of thousands of chevrolet and gmc pickups, suvs, and vans from 1996 to about 1998, so they are easy to find and relatively inexpensive to build. These heads are good for a minimum 50hp gain. My vortec heads are good to.500 in/.530 ex (with 'forgiveness' in mind) with common components used and absolutely no machining done to the heads valve guides/spring pockets. The cam is based on the maximum lift for stock vortec heads and is a single pattern 215d/470l on a 112 center. Starting in 1996, on several gm trucks and vans, the l31 vortec heads came on the scene.
Vortec head valve geometry....rocker stud issue ... from i617.photobucket.com Vortec head modifications hi everyone, im looking to modify a set of vortec heads for oval track racing application. + up to.550 lift on vortec heads w/ no mods! My vortec heads are good to.500 in/.530 ex (with 'forgiveness' in mind) with common components used and absolutely no machining done to the heads valve guides/spring pockets. Can be machined for 2.020/1.600 valves. The stock valve job can be improved on vortec heads. Tony, just remember that total lift is the cam lobe lift and the rocker arm ratio for total lift. The l76 is a gen. I am not going to install lash caps.
Tbi to vortec head conversion gmc truck forum / vortec heads also use a different intake bolt angle than traditional sbc heads and, as mentioned previously, camshaft lift needs to be kept on the low side, unless other modifications are made.
I ported mine and fully worked the exhaust port (bowl work and contouring the runner). Im trying to make them suitable for my selected camshaft. Valve spring seat diameter is 1.280. This is the speed secrets episode for you! Starting in 1996, on several gm trucks and vans, the l31 vortec heads came on the scene. The cam is based on the maximum lift for stock vortec heads and is a single pattern 215d/470l on a 112 center. Tony, just remember that total lift is the cam lobe lift and the rocker arm ratio for total lift. Discussion starter · #1 · jun 15, 2005. The l76 is a gen. Rocker arm studs can be pinned or drilled and tapped to 3/8. Camshafts with more than 0.475 lift require machining valve guide bosses and checking valve seal to valve spring retainer clearance. This vortec design special performance cast iron cylinder head features revised intake and exhaust ports and is machined for 2.00 intake valve and 1.55 exhaust valves. Modifications thus far consist of cam swap /edlebrock 2162 500/500 112 degree ls, edlebrock tube headers running into stock single exhaust, tbi harris towmaster chip.
Featuring the comp cams xm270h ca. Iv engine based off the ls2, which was also produced both as a car engine and a truck engine. There are other, smaller points that are important to know because they affect cam selection. We used up about 10 heads, numerous valves, and about $50,000 worth of labor. By changing the springs, the distance between the retainers and the valve seals hasn't changed.
Edelbrock 60989 Performer Series RPM E-TEC 200 Cylinder ... from www.catalograck.com Tony, just remember that total lift is the cam lobe lift and the rocker arm ratio for total lift. So the best bang for the buck is gm vortec head but does require a special intake and lots of egr work if you need egr to remain emission legal. The stock valve job can be improved on vortec heads. I will need to cut (reduce the height) of the valve guide boss.this is the curse (or part of the curse) of the vortec heads. Rocker arm studs can be pinned or drilled and tapped to 3/8. Im trying to make them suitable for my selected camshaft. Gm also sells vortec pattern intakes for tbi and 4bbl's. Camshafts with more than 0.475 lift require machining valve guide bosses and checking valve seal to valve spring retainer clearance.
Joined jun 15, 2005 · 2 posts.
For stock cam, heads and cr that's very good. Valve spring seat diameter is 1.280. As illustrated in the pics in post #60; We used up about 10 heads, numerous valves, and about $50,000 worth of labor. Featuring the comp cams xm270h ca. Iv engine based off the ls2, which was also produced both as a car engine and a truck engine. Starting in 1996, on several gm trucks and vans, the l31 vortec heads came on the scene. I have a set of 1998 5.7 vortec heads # 10239906 and replaced the stock cam with marine cam about.470 lift. All the parts are included and they sell for about $680 a pair. These heads are good for a minimum 50hp gain. Can be machined for 2.020/1.600 valves. The worst piece on the whole tpi system is the cold start injector or referred to as the 9th injector. The real weakness of the vortec head is the exhaust port, a fact that is readily apparent when you get into porting these heads.
