How much diff. would a set of vortechs make on my setup I have in my sig.? Would I be able to use my existing intake, or an RPM? Any idea of power difference if I use Vortechs over the TBI's

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'87 Camaro Iroc-Z
'92 350 .040-over
Mild Cam
700R-4 w/shiftkit only.
Edelbrock Perf. manifold and Carb(600cfm#1406)
GM HEI upgraded with Accel parts
TBI truck Heads

 

it will give a great increse over the stock tbi smog crap heads,...but the intake thats another question ..just buy the special intake for the vortecs and save yourself the trouble. unless your good at african american rigging!!

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89 firebird formula

356 10.5:1compression CURRENTLY DEAD!!! BEARING FAILURE!!
comp cams xe262 cam
performer rpm intake
#1405 edlebrock 600
sportsman 2 heads 64cc 2.02/1.60 valves 200cc intake runner
msd 6al
h.e.i. proform 50,000 volt vac. advance ditributor
700r-4 with 3.08 first gear and 3.23 posi 7 5/8 rear end.
b trans shift kit(will kill shifts...suck dong!!)
shorty heddman hedders with custom 3" pipe y-pipe back(no damn cat!) with 40 series flowmaster!


future mods: 406 roller REALLY REALLY REALLY RADICAL!!!!!

 

PPont,

You didn't define the meaning of "mild cam", so it's difficult to say if the heads will just bolt on. The intake bolt pattern of the Vortec heads is slightly different (more like the LT4 design) but many intakes can be altered to match with a little dilligent machining.

The problem with the Vortec heads in stock trim is the limit to valve lift. The valve guide bosses are taller than the "standard" SBC heads,so there can be interference between the spring retainer and upper end of the guide at lifts approaching 0.480". To avoid crunching the camshaft, lifters, and push rods, you'll need to machine the guides lower. You might as well machine for teflon stem seals while you're there, as well as screwed rocker studs and larger valve springs. And as long as the heads are under the mill, enlarging the valve bowls can improve mid-lift flows, and some short-side radius recontouring would help on the exhaust side, since the Vortecs are a little restrictive in that area. If you're going that far, the wimpy little 1.94/1.50" valves on the Vortecs should be opened to at least 2.02/1.60" with the appropriate seat hardening.

For all you'll spend at the machine shop to get the Vortecs in good trim, you might be better off getting some Edelbrock Performer heads, since they already arrive with the larger valves, screwed studs, springs rated to 0.575" lifts, and ports machined to flow more like what you expect. They also fit the OEM-design manifolds without changing the bolt patterns. Unless you are getting the heads for free and can do a lot of the machining yourself, they might be more costly than good aftermarket heads.

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Later,
Vader
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