well for starters, you either do NOT have the Victor jr that u stated, or 2, you do NOT have Vortec heads....There is NO vic jr for the vortec heads!

 

http://store.summitracing.com/partde...9&autoview=sku my bad its just a victor manifold

 

That intake is still not for the 96' & later Vortec cylinder heads. It would fit the 88-95 Vortec heads with a little work making the center 4 bolts of the manifold bigger for the different angle. If the intake only has a total of 8 bolts holding it down then it is for the 96 & later heads. If you have 12 bolts holding the intake down then you have one of GM's worst flowing heads ever produced for the 350 motor.

 

it has 8 bolts

 

88-95 is TBI swirl port, not vortec in any way, just center bolt valve covers.

 

Sorry but the link that you posted is for a older SBC.

 

Yes, well GM still called them Vortec motors and alot of people think that they have the "Vortec heads". In the link from Summit Racing that the OP posted, it has a Super Victor intake for an older SBC, which lead me to believe that he had the TBI heads.

 

One question or bit of info, I didn't what type of cam.. hyd.. hyd roller or solid ?.. (to lazy to look it up).

Might have a bit of a problem with any Hyd getting above the 6.5k mark.. so.. more info on the valve train ! Spring pressure at open/close, etc..

 

I just bought a rev kit off Ebay for 17$, it is great for that extra RPM, supposed to help get 1000 RPM is some cases.

 

Mechanical Flat Tappet, Advertised Duration 290/304, Lift .540/.534

 

I wonder why people say 7k can't be done in a hydraulic roller SBC? LS1s do it all the time with factory lifters without rev kits.

If you go with the AFR Eliminator heads (and thus lightweight LS1 springs - especially the 8019s with 155lbs seat pressure), Morel lifters (much better with high seat pressure, high lift, and valvetrain stability at high rpms), any good aluminum rockers (or to be safe, Jesel shaft mount rockers), stiff pushrods (7.200" on a 87+ SBC helps, but a 3/8" Manton pushrod = teh shizzle), and a Comp XE or Lunati Voodoo lobe cam, you can see 7k with the right carb/intake/exhaust.

?!

 

Ever compared valvetrain in a GEN I and a GEN III? The SBC valves are SERIOUSLY heavier. Valvetrain weight is really the secret to LSx technology for higher revving, the difference in heads helps but without the lighter hardware it wouldnt be too much different.

 

There are more important differences than the valvetrain weight. The Dart LS1 heads use 11/32" valves just like Gen 1's and they keep up with the CNC ported heads, as cast. The 15* valve angle heads are a major key to the better performance. Then there is the equal valve spacing on the cylinder heads. I would say the next thing would be the shape of the runners and then the valvetrain weight.

 

Mostly b/c of mis-matched parts selection!

 

Well, the AFR Eliminators have LS1 valves too.

 

The springs also help on the Dart heads too. The 15 degree heads healp but i have seen a comparison of 406 to 408, the LSx platform made only 25 more HP. That is not much really, considering the 406 had 23* heads still.

 

Lets do a comparison between a pump gas 406 23* hyd roller motor vs. my cousin's DD LS2 403. https://ls1tech.com/forums/showthrea...ght=latest+403 Let me know when you get these kind of results.

 

One other thing that really helps LS1... 55mm cam core. Bigger, badder lobes can be used with more lift without killing valvetrain stability.

 

Thats not stock degree heads....

 

I bet if they were changed out to AFR 225's there would be next to no change in the HP & TQ.