New Heads: Vortec 2.02" / 1.6"

Discussion in 'Performance & Fuel' started by 04SilveradoMykk, Apr 7, 2009.

  1. 04SilveradoMykk

    04SilveradoMykk New Member

    Hello Everyone,

    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

    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


    Cheers ~Mykk
  2. 95CTburb19

    95CTburb19 New Member

    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?
  3. 04SilveradoMykk

    04SilveradoMykk New Member

    Tore her down last night. Or as my buddy put it "Rip & tear to no dispare"


    LT4 hotcam is out


  4. 04SilveradoMykk

    04SilveradoMykk New Member

    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

    Cheers ~Mykk
  5. dwill3015

    dwill3015 New Member

    Nice job and great pictures as always Mykk! Can't wait to hear what She's like when you get done tonight.
  6. cascott325

    cascott325 New Member

    that truck is one hell of a project. its is amazin what all you have done to it. keep us in the loop
  7. 04SilveradoMykk

    04SilveradoMykk New Member

    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


  8. 04SilveradoMykk

    04SilveradoMykk New Member 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

  9. 04SilveradoMykk

    04SilveradoMykk New Member

    A vid of the final product, after switching the edelbrock 1405 for a Speed Demon 650cfm

    [ame=""]YouTube - Chevy 350ci: Comp cam, Speed Demon carb[/ame]
  10. Timberwolf

    Timberwolf New Member

    That truck sounds completely NASTY!!! I LOVE IT!!

    Beautiful truck... thanks for posting the video.
  11. 04SilveradoMykk

    04SilveradoMykk New Member

    A few pics from recently swapping the heads again. May as well update an old thread then create a new :)


    I was running into piston to valve clearance issues, the marks were caked under a layer of carbon from burnt oil. I suspect it was valve float.


    The replacement heads are a set of Pro-Comp, aluminum 210cc runner/58cc chambers, angle plugs. I opted to use head studs to help remove variables.


    The reason I chose budget castings were because I wanted to experiment with a few internet myths. Somender Singh grooves and chamber dimpling.


    Starting with the 58cc chambers and assuming going as large as 61-62cc's after groove and dimpling, with the .026" MLS head gasket the static compression should be around an even 11:1 with a .030" quench. Before bolting the heads down I checked piston to valve interference with playdough in the valve reliefs. Bolted the heads down without a gasket and then made a simulated "solid" lifter from an old hydraulic one and ran half a dozen cycles on the intake an exhaust. The valves barely made an impression in the play dough. PTV clearance checked good.

    Increased capacity oil pan:


    Proform 2 piece valve covers, new MSD cap/rotor & custom made wires to sneak under the headers.


    Painted the engine bay, cleaned up some unused wiring harnesses. Tucked away and hide the remaining wiring. Right now I have the heater hoses removed, I'd like to come up with a creative way to plumb and hide them.



    New MSD digital 6a, Mallory coil. Still trying to hide as much wiring as possible.


    The day I got it fired up and on the test drive it grenaded another 4L60E, the third one for this truck.


    The torque converter cracked at a weld on the snout too.


    Ordered a new converter. a 10" 2800-3200rpm stall, non-lockup & anti-ballooning plates:


    In the process of getting it back together and will hopefully be able to drive it, cruise it and hammer on it without any other major problems.

    I've got a few more toys to play with once it's up and going again. I have a few carb spacers to run through and even stack different ones. Also have an oil catch can to mount, I'm debating installing an electric vacuum pump to draw through the crankcase too.

    I plan to spend a very long time dialing in the carb tuning with use of a wideband O2 gauge.

    Cheers ~Mykk
  12. Pikey

    Pikey Moderator Staff Member

    Wow! Sweet truck.
  13. 08_rado_rocker

    08_rado_rocker New Member

    damn. Very nice truck man. Hope all goes well and you actually get to drive your toy lol! :rofl::great: big fan!

    - - - Updated - - -

    Kind of curious to know why you did away with EFI.. always see people putting EFI on rides that were Carb'd, but hardly ever the other way around. It seems as though you have lots of insight into the hot rodding portion of the site, so I'm interested in hearing your reasoning!

    - - - Updated - - -

    Another question. Did you go with solid mount? That thing didn't budge at all in the engine bay! If so, are your trans mounts solid as well??
  14. 04SilveradoMykk

    04SilveradoMykk New Member

    Rado Rocker, (Usually I get asked why did I install a genI SC and not an LSx) there is a looong answer and then a simple one to your EFI question. The simple answer is, cost. It would cost 3-4 times as much in EFI components to go this fast with the carburetor alternative.

    The looong answer. When I first built this engine in 2008. I didn't really have a purpose or a home for it. The block fell in my lap and I took it on as a project to build and maybe flip or perhaps drop it in a future rod project. Then I got this idea to replace the 4.3L V6 in my silverado with a mildly built vortec/L31 fuel injected engine:


    Afterall, I'd be keeping a similar style fuel injection and engine design but just two more cylinders right?


    It was a tuning nightmare. I even re-wired and re-pinned the wiring harness for an 0411 PCM. Still couldn't get it to run right. Months of dataloging, tweaking, adjusting the tune. Even with the fuel trims withing 2%error and what I considered an aggressive ignition timing table just below the threshold of knock. It was gutless, could barely keep up with traffic and was drinking 10-ish MPG. Admittedly the L31 vortec fuel injection isn't a known performer, but it's not nearly as bad as this engine was acting.

    I checked cam timing, fuel pressure, crank to cam correlation, to no avail. I finally decided to make the jump from EFI to carb. I picked up a chinese performance intake manifold, edel carb and inexpensive distributor. Bolted then down, dialed them in, fire it up. And peeled the tires off the rims on the test drive. From there I was carb hooked (on this engine).

    I installed better heads, a bigger bump stick, increased compression and bolted down a highly tunable Mighty Demon 750cfm.

    Going from EFI to carb shaved over 3 seconds off the 1/4 mile time.

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