600hp blue thunder build info (the large port vortec heads)

[grumpyvette]

http://www.chevyhiperformance.com/techa ... index.html
this at first seems like a killer combo untill you read deeper and understand the total build,details and the expence they went thru, but THERES NO DOUBT the large port vortec heads certainly have FAR more potential than the smaller versions and would be a decent choice on a high compression ratio 383-427 SBC COMBO with a decent roller cam for a street/STRIP APPLICATION combo

http://www.chevyhiperformance.com/techa ... index.html

http://www.crateenginedepot.com/store/B ... 857C0.aspx

http://www.chevyhiperformance.com/techa ... ewall.html

http://www.sdpc2000.com/product/2553437 ... rHead.aspx

read thru this, its basically an engine build where they use all the tricks to get a fairly stock set of mildly reworked large port vortec heads , with a much improved valve train to produce thier max power

now those heads, intake and a milder roller cam, would be more useful to most of us ,on a slightly less exotic 406 or 383 SBC combo

Vortec Bow-Tie Brief
There are two versions of the new GM Performance Parts Vortec Bow-Tie cylinder heads: This one, PN 25534371 (bare) and PN 25534431 (complete), with the larger ports, and another with smaller ports, PN 25534351 (bare) and PN 25534421 (complete) with 185 and 65cc volume, otherwise, the architecture and improvements over the L31 design are the same. We will test the smaller version very soon in a dynamometer exercise. We were able to get an exclusive look at the big-port heads just as they were used in a NASCAR-type application.

Out of the box, they feature revised intake and exhaust ports and are machined for a 2-inch intake and 1.55-inch exhaust valves. The deck surface is 0.045-inch thicker than the L31s, and it has 65cc combustion chambers, a 206cc intake, and 77cc exhaust ports (see Flow Chart). The head is also machined for 3/8-inch screw-in rocker studs and a large valvespring pocket, and it will accept up to a 0.530-inch lift camshaft without modification. These castings are identified by the Bow-Tie logo below the exhaust port and the Vortec logo on top of the intake port area. The GM logo is also cast into the bottom of the intake port runners.

All concerned will be delighted to hear that the head includes intake manifold mounting holes for both early-model six-bolt and late-model four-bolt Vortec design. Mandated GM intake manifolds include a raised runner-type PN 10051103 (six-bolt type) or Vortec design PNs 12366573, 12496820, 12496821, 12496822, and 12499371 (four-bolt type). Though production cylinder head and intake manifold gaskets are acceptable, the hot squeal is Fel-Pro (PN 1142 for the MLS and PN 1289 for the intake). As per Scoggin-Dickey, pricing is: small port 4421 complete, $499.95; small port 4351 bare, $269.25; large port 25534431 complete, $539.95; and large port 25534371 bare, $293.25.

http://www.superchevyperformance.com/Vo ... 534431.htm

http://paceperformance.com/index.asp?Pa ... dID=104477


SMALL PORT VORTEC INFO

http://www.2quicknovas.com/vortecheads.html

http://sallee-chevrolet.com/Cylinder_Heads/Vortec.cfm

http://purplesagetradingpost.com/sumner ... eads1.html

are you aware theres a far better 215cc vortec head available?

http://www.crateenginedepot.com/store/B ... 57C65.aspx

viewtopic.php?f=52&t=266&p=322&hilit=215cc+vortec#p322

viewtopic.php?f=52&t=731&p=1028&hilit=215cc+vortec#p1028

http://sdparts.com/details/gm-performan ... s/25534431

http://www.chevyhiperformance.com/techa ... index.html

casting numbers
10239906 and 12558062..96-up...350.........."Vortec 5700", "L31", 64cc chamber,
170cc intake port, 1.94"/1.5" valves

 

[grumpyvette]

Large-Port Vortec Cylinder Head Flow
INTAKE EXHAUST
Lift Volume Lift Volume
0.200 128.6 0.200 100.8
0.300 188.4 0.300 138.6
0.400 234.8 0.400 154.4
0.500 257.2 0.500 152.5
0.600 263.2 0.600 163.8
0.700 269.1 0.700 167.0


The 355 Numbers
RPM Torque (lb-ft) HP
4,500 457.8 392.2
4,600 468.7 410.5
4,700 474.9 425.0
4,800 484.3 442.6
4,900 489.6 456.8
5,000 494.4 470.6
5,100 497.6 483.2
5,200 498.6 493.8
5,300 501.3 505.9
5,400 499.9 514.0
5,500 503.2 527.0
5,600 500.8 534.0
5,700 500.9 543.6
5,800 500.2 552.6
5,900 502.5 564.5
6,000 501.8 573.3
6,100 500.5 581.3
6,200 498.6 588.5
6,300 497.2 596.4
6,400 493.8 601.7
6,500 492.5 609.5
6,600 487.7 612.9
6,700 482.7 615.8
6,800 475.8 616.0
6,900 470.3 617.9
7,000 464.4 618.9
7,100 462.1 624.7
7,200 458.2 628.2
7,300 452.8 629.3
7,400 445.9 628.2
7,500 443.1 632.7
7,600 435.5 630.2