Building the Vortec 357ci
You've been such great help here while building my S.B.C. Every hurdle I've had to jump has been with great help & support from HotRodders.com
So here this is what I have been up to:
Started with a 86-95 4 bolt main block, one piece rear, roller cam block
Honed it out to new H345NCP-40 pistons.
Balanced a take-out forged ZZ4 crank & rods with a new balancer & dampener
Stabbed in a LT4 Hot Cam
cleaned up a pair of Vortec 906 heads. Drilled out the pushrod holes to 1/2", Bowl Hawged the intake & exhaust, gasket matched the intake ports & intake manifold, pinned all 16 press in studs and cleaned up the rough castings in the exhaust ports.
Sneaked a Summit quiet geardrive and the crank position sensor reluctor wheel behind the plastic vortec timing cover.
Assembled the heads with new 1.94" / 1.5" swirl polished valves. Comp Beehive springs & Proform 1.6 ratio roller rockers
Droping in the new Updated Vortec fuel injection spider
bored the vortec upper plenum from 72mm to 74.4mm to match the larger CFM-Tech throttlebody
Welded a pair of O2 sensor bungs to the Hooker Headers 2462 long tubes
Put on the rear main seal retainer & oil pan and there she is... my S.B.C.
She's not 100%, as soon as it's off the stand I can tap in the remaining two expansion plugs & cam plug.
This pic was a mock up before the final assembly, but gives an idea of what she'd look like. Thus the lack of bolts.
Best of all, it rotates freely... no binding up, no PTV issues,no coil bind, no retainer to valve seal interferance, no geardrive & CKPS reluctor interferance.
357ci: 4.040" bore x 3.480" stroke, 5.7" rods
Hypereutectic Aluminum flat top ( 4 valve relief) pistons sit .004" in the hole, with Felpro 7733pt head gasket (.039" compressed) will have a .043" quench height.
Estimated 10.2-1 static compression ratio.
Valvetrain: LT4 Hot Cam, 1.6 rockers
Lift @ .050":.525" I / .525" E
Dur @ .050" 218 I / 228 E
112* lobe seperation, 108* intake centerline
To help this valvetrain function in a 4380lb pickup here is a 3000 stall locking torque converter for the 4L60E
Desktop Dyno puts this motor @
421ft-lbs TQ @ 4000rpm
..but I also have my single fogger 75 shot of wet nitrous.
Carcraft did a build using the same block, heads & valvetrain and came to:
401HP @ 5600rpm
428ft-lbs TQ @ 4200rpm
The only differences were they were carburated & stock bore & less compression than mine. So we'll see what happens.
Last edited by 04SilveradoMykk; 08-20-2008 at 09:20 AM.
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