Vortec Cylinder Heads: The Definitive Guide

Discussion in 'Engine Topic' started by MikeM79, Jul 4, 2006.

  1. upcwhiting

    upcwhiting New Member

    Nov 26, 2006
    Hi. I saw this post here concerning the Vortec heads on your car but you didn't give any vehicle specs; type of car, race weight, trans type, rear gear, induction. It would help to know this. I have a new 355 Vortec motor I just installed in my '72 Camaro but I don't have it hooked up yet or running. Thanks.

    Richard Whiting
    Palominas, AZ

    Attached Files:

  2. Urban Samurai

    Urban Samurai Veteran Member

    May 3, 2006
    Sorry about that. I have a 72 Camaro. It has a fiberglass hood & doors, rest is glass & steel. Not sure on weight, was 3300 with big block. I'm running a TH350 trans @ 3:90 gears.
  3. MikeN

    MikeN New Member

    Jul 20, 2017
    Forgive me if this has been asked and answered, I didn't see anything via the search engine...

    I have a set of the EQ CH350H heads, which have the 55-86 intake bolt pattern. The top of the intake port on these heads is really high. It doesn't look like my Edelbrock Performer RPM Q-Jet intake will work. Is there an off-the-shelf intake I can use?
  4. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

    Nov 4, 2004
    Ringgold, GA
    I don't have any experience with that head but Competition Products description says; 69-86 Intake Manifold Bolt Pattern, so just a plain sbc intake should fit. You might want to contact who you bought these from and see if there's anything special you should know. You can also use a cheap set of intake gaskets, set the manifold on and check clearances.
  5. larrylarry

    larrylarry Veteran Member

    Dec 22, 2011
    San Antonio Tx
    Like how high? If you have a dial caliper you can measure the difference. Thing is the height is should match up, you can have the bottom not match up to a certain degree & not hurt flow but height is important.
    FYI intake port matching to the head ports really doesn't have as much of an effect as you think but I still do it.
    Last edited: Jul 21, 2017
  6. Joshua Coomes

    Joshua Coomes New Member

    Sep 3, 2017
    Ok,. I joined this page because you guys put together an amazing thread. I made it to page 23 and a have long way to go. I am asking a question on camshaft.

    I have a stock early HFT TBI 350 with the summit cam below. It's a 218/218 with .458 lift on 110 LSA. I am putting on a set of EQ Vortecs that the person I got them from does not know the specs on the valve train. He knows it has comp steel rockers. I am planning on my CR to be about 9.75:1 or so. I am unsure of my piston to deck, and I am planning on running a .015 shim head gasket.

    I was planning on upgrading to a dual pattern cam, but I am not sure if I am going to see a big difference. I need to check for allowable lift, coil bind, and spring pressure. If I get a new cam, I don't want to wipe out a lobe during break in. This 350 will be fuel injected with a Holley TBI with a custom computer using speed density, so I believe I should stay away from anything lower than 108 or 110 LSA. My truck has 13-15" of vacuum right now.

    So, I am wanting a hot street setup, hoping for 13-15mpg at minimum. I will be running 3.42 gears with a 28" tire through a lock up 350. I have a 2400 stall converter. I have a summit rpm air gap copy manifold and cheap 1 5/8" long tubes and a 2.5" dual exhaust with x-pipe in a 85 c10 Longbed.

    What do you guys think?

    Attached Files:

    Last edited: Sep 3, 2017
  7. SERacer

    SERacer New Member

    Oct 23, 2017
    Circle Boat

    Here are some class rules:

    4.060 max bore
    3.5 Stroke
    Flat Tappet Cam
    1.5 Rockers Any Type
    .450” Max Valve Lift
    As Cast 170cc Factory Intake Port Volume Max
    1.945 Max Intake Diameter (Steel or SS)
    1.55 Exhaust Diameter
    1.25 Max Spring Diameter
    As Cast Aftermarket Intake (Cast)
    .5”-2” Carb Spacer
    4776 Holley 600DP Carb
    No Step Headers
    Flat Top Pistons with Valve Reliefs
    HEI Ignition

    These are the rules, boats are pretty much full throttle for 5-10 laps.

    Spec out your engine. How you build this engine to achieve maximum horsepower? What engine temps do these Heads like to see to keep them together and for HP?
  8. TheMadDoctor

    TheMadDoctor New Member

    Apr 21, 2010
    Orlando, Fl
    Wow, I just read the whole 99 pages of this sticky, and still have questions.

    I am planning to rebuild the 400 sbc that's in my car, and I have a chance to buy some really nice rebuilt vortec. 062 heads with beehive springs and guideplates already installed. Im worried that my compression will be too high with 64cc chambers.

    Assuming that I keep the stock bottom end, with new bearings and rings, I would be looking at a 10:1 CR. Would that work with pump gas and still be good for a daily driver?

    I know cams have alot to do with it, and Im worried that I will need a cam too big for my stock converter and 2.41 rear gear. I would really like to use the smallest cam that I can to boost low end torque and enhance gas mileage. The engine will never see over 4000rpm.

    Currently I have 339x heads, I don't know the cam specs, the guy I bought the engine from said it was a 3/4 race cam, a th350 , 2.41 posi gears and an eddy 600 carb. The car runs great except for the oil leaks, and low oil pressure. I've been driving it for 17 years, so she needs freshened up. Any help you could give me would be appreciated!
  9. larrylarry

    larrylarry Veteran Member

    Dec 22, 2011
    San Antonio Tx
    I thinking your compression will be higher than 10:1 if you use the Vortec Heads because you have a larger piston. Standard 400 pistons are 4.125, standard 350 pistons are 4.00. A slightly wider piston will raise compression. Those 339 heads have a 76cc chamber, Vortecs 64cc but actually their 62cc if they haven’t been messed with. Plus you’d have to drill steam holes in the Vortecs also. I’d scrap the idea.
  10. 79RedZ

    79RedZ Veteran Member

    Mar 24, 2009
    What pistons do you have in that 400? Flat top or dish?

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