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Thread: New Heads: Vortec 2.02" / 1.6"
04-08-2009, 12:58 AM #1
New Heads: Vortec 2.02" / 1.6"
I've decided to retire my current set of worked over OE 906 Vortec heads. After the umpteenth time of re-adjusting my rockers and setting valve lash, not but just minutes after the fire up the valve train sounds like a diesel again! My assumption, something happened during the pinning of the press in rocker studs to weaken them or the COMP 26918 beehive springs with 774 retainers has created too much spring pressure and has wiped out the GM roller lifters. Either way, parts are going to need to get replaced.
I recently sold a few misc parts I had laying around my garage, via EBay. And in a short period of time aquired enough $$ in my paypal account to purchase a new set of heads. I found this pair of Vortecs from a company called J&C enterprises, and what had me sold was the fact they were new. (And the 2.02" / 1.6" valves didn't hurt either)
Fast forward a week, the UPS delivery arrives and I unbox my new pair of Vortec heads.
However, I couldn't find any kind of info about this casting #
After doing a bit more research on these heads, I discovered they are made by Patriot. I know alot of guys swear Patriot is junk (and I have seen the pictures too), but I've inspected these heads closely (without a tear down) and have seen nothing but nice clean machining and clean castings. I was curious as to what the advertised flow numbers were and how they compared to other Vortec SBC heads on the market. Here is what I found...
Stock Vortec 906: (according to chevymania.com)
Intake / exhaust
.100" 70 48
.200" 139 101
.300" 190 121
.400" 227 140
.500" 239 147
.600" 229 151
Patriot 2.02" / 1.6" - 185cc intake / 60cc exhaust (from patriots website)
(@ 28" water)
Intake / exhaust
.100" 74 50
.200" 140 99
.300" 202 145
.400" 235 175
.500" 241 183
.600" 246 190
Edelbrock E-tec 60979, 1.94"/1.5" - 170cc intake / 70cc exhaust (from edelbrocks website)
Intake / exhaust
.100" 64 54
.200" 122 96
.300" 177 124
.400" 217 147
.500" 229 166
.600" 232 175
Edelbrock E-Tec 60689, 2.02"/1.6" - 200cc intake / 80cc exhaust (from edelbrocks website)
.100" 67 57
.200" 122 110
.300" 175 153
.400" 223 182
.500" 252 196
.600" 259 204
Those are some pretty competitive numbers by patriot. Especially for the price, all they need is a little bit of exhaust port work and they could provide some very stiff competition to the more expensive big boys
Ok, so the heads are adressed. What about the valvetrain?
Everytime I've had the valve covers off my SBC I thuroughly inspect my Proform 1.6 ratio aluminum roller rockers for any wear/damage/problems, just from reading the horror stories. But I can not find anything wrong with them. So I will re-use my Proforms, Since the lifters are suspect of a problem I decided to replace them all with a set of COMP 875-16 roller lifters that will work with the OE lifter retainers & cage.
Since the intake manifold & heads will be off and the cooling system drained anyway I figured I'd take advantage of the oppurtunity and go one step further. I decided I was going to replace my LT4 hotcam with a bumpstick that would offer a bit more duration and since fuel injection is no longer a concern perhaps a tighter lobe seperation too. That and something I can take advantage of my 3200 stall converter, long tube headers & 4:10 gears. The cam I found that would meet my needs, the COMP XR276HR-10 coupled with my 1.6 rockers.
And from what I can see, the Patriot vortec heads are a good combo for this cam too. They can accomodate a max lift .575" and COMP recomends their 986 or 987 springs with this cam @ 322 & 344lbs/in, while the patriots come with closed pressure 115 lbs. @ 1.800" open pressure 310 lbs. @ 1.225" (.575" lift)... thats a pretty good match.
Right now, my SBC is:
4.040" bore x 3.48" stroke
4.1 x .039" head gasket
flat top pistons, four valve relief -5cc
.004" from deck
equals 10.34-1 compression. While I need to replace it anyways, I decided I would use a Mr.Gasket 1134 head gasket 4.13"x.028" to bump my compression up to 10.6-1 (probably a 10.5-1 with compression loss through the cam) wich would still be a 91 octane pump friendly street driver.
What's the estimated power output after all the new goodies?
Desktop Dyno puts the combo @ 449HP @ 6000 / 445TQ @ 4500.. and an amazing 406TQ @ 2500
Vortec 357ci Small Block Chevy: Big cam, high stall, long headers, rear gears. The typical formula.
04-08-2009, 11:13 AM #2
Wow sounds like that's going to be an awesome motor when you're done. Are those power numbers at the crank or is that rwhp?Dan
1999 GMC Sierra 2500 350 vortec
1967 Jeep M725 ambulance 230 tornado
1990 Cherokee Limited- 3 inch lift on 33's
...and every one of em has issues
If you have any questions or problems don't hesitate to send me or any other GMTC moderators a PM
04-18-2009, 09:39 AM #3
Tore her down last night. Or as my buddy put it "Rip & tear to no dispare"
LT4 hotcam is out
04-18-2009, 09:40 AM #4
New COMP XR276HR-10 camshaft is in
Even though these were new heads, I found some warpage in the gasket surface and ended up milling .008" off each head
Tonight after work I'll transfer over the COMP 26918 springs from the old heads to the new, using the new COMP 787 retainers.
Bolt down the heads, and put everything back together. And hopefully, if everything goes smooth I'll drive her home tonight
04-18-2009, 10:18 AM #5
- Join Date
- Jan 2007
- Yacolt, Washington
- Blog Entries
Nice job and great pictures as always Mykk! Can't wait to hear what She's like when you get done tonight.Darcy
2006 Silverado 2500HD LT3 4X4 CC SB Duramax LBZ
Tuff Country 6" lift, 35" Toyo M/T's on 20" Ultra Peacemaker wheels, Quadzilla Stealth2 programmer, Diamond Eye 5" cat-back exhaust, factory Special order color Yellow.
04-18-2009, 10:31 AM #6
that truck is one hell of a project. its is amazin what all you have done to it. keep us in the loop2000 silverado with a 5.3l v8, shorty headers, upgraded plugs, 10 mil wires, magnaflow high flow cats, flowmaster 80 series muffler(2 in 2 out) w/ 18 inch stainless silverline tips. i have a k&n CIA. its a 4x4 z71 offroad package. Ls model.
extended cab 160k miles, truxedo low profile bed cover, diablo sport predator tuner.
reman tranny @ 130k miles
04-19-2009, 05:05 AM #7
Didn't get as far as I would have liked, I stopped at about 1:30a while I was still thinking clear before I started making mistakes.
Heads assembled & torqued down with 26918 springs & 787 retainers.
valvetrain is adjusted per comps instructions using their 875 lifters
Those spectre "fabbed" aluminum valve covers do look pretty mean
04-19-2009, 05:05 AM #8
...here is to show the difference between the Comp 787 vs 774 retainers on the 26918 when installed on gen IE vortec heads
787 on the left.....774 on the right
The comp 26918 springs, 787 retainers & proform 1.6 ratio aluminum roller rockers
05-04-2009, 12:39 AM #9
A vid of the final product, after switching the edelbrock 1405 for a Speed Demon 650cfm
[ame="http://www.youtube.com/watch?v=D7vtulnfwPU"]YouTube - Chevy 350ci: Comp cam, Speed Demon carb[/ame]
05-04-2009, 07:42 AM #10
- Join Date
- Sep 2008
That truck sounds completely NASTY!!! I LOVE IT!!
Beautiful truck... thanks for posting the video.
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