ok i'm gonna be using a 96 yukon 350 block. 1pc rear main seal. 4bolt main.
power house 383 kit. 10.8:1 compression with a 68cc head
(i will be changing out the pistons to 15cc dishes 4 valve relife so i can use vortec heads)

rpm air gap intake with holley 4160 750cfm vac seconday

vortec heads with lt1/z28 springs and retainers
1.5 crane gold roller rocker

hyd. roller cam
.462 intake lift @.050 w/ 210 deg
.470 exhaust lift @ .050 w/ 215 deg
110 lsa

hooker shortie headers to cut outs


how's this sound?? any changes you would make to this??

 

Change the springs. Get a spring that matches the cam and/or from a major cam company. Comp, Crower, Isky, Lunati, etc. GM does not fall in that list. Get Comp 986 springs. Or, if you don't feel like having the spring seats cut, Isky makes a 235-D springs, which is very similar in specs to the 986, but it fits the factory seat.

 

Why VS?

 

cause i got it for cheap. you don't think the 750 is over doing it do you? and also i like vacum secondarys alot more for being a streetale car. scnince they don't just dump gas in at certine throtel it relies on vacum and that is created at rpm. so much nicer in my mind

 

It's not too big.

It is possible for a VS to open at less throttle than a DP will. That's because the VS opens based on primary flow (not RPMs). It's typically worse with an undersized or very close to minimum-sized VS carb, admittedly.

VS will take longer to close than DP. It can feel pretty weird if you're not used to it.

 

i had vac secondarys on my q-jet but should it feel diffren't then that. also any one have a gussetimation on what kinda hp / tq this think will make

 

The q-jet air valve and the Holley/Demon vacuum secondary operate on completely different principles. I went from q-jet to 750 Holley VS on the 396 - it was that transition that "surprised" me for the effect mentioned.

You should be in the 400+ range torque and HP wise.

 

so those lt1 springs aren't a good choice they fit my recomended lift and all. and i was told thier a dircert fit and the mechining for them is free cause i'm doing this in my shop class