more POWER!? 302

Discussion in 'Ranchero Tech Help' started by Johnnycoast, Apr 24, 2019.

  1. Johnnycoast

    Johnnycoast In Second Gear

    Im in the market for new aluminum heads, because I want higher compression and more power. Basically Id like to get the max power you can out of this without stroking it. I kick myself for not making it a stroker when I had the chance. I had the motor rebuilt, AAANNND that would have been the time to stroke it......
    The mechanics who rebuilt it urged me to put a 351 mild cam in it. I didnt know too much about it then and just wanted to get the car running. (I dont think it made much of a HP gain, Im chalking that up to folklore)But now I want to mess with it more of course, because cars r fun, ha.
    So its rebuilt,
    351 "mild" cam
    bored .030" over
    new edlebrock 600 cfm carb
    edelbrock manifold.
    There is a really great article on line by Hot rod mag that tests 3 or 4 different heads, edelbrock e street series came in second, the first required some mods to the heads to make them go...
    It does note, that the high horse power was helped out a lot by the larger valves, that require more clearance on the piston head, not the stock ones... which they prob put in mine when rebuilt, another kick in the ass.
    Im seriously looking at the top end kits jegs offers as a package.

    Edlelbrock E street heads.
    Edelbrock RPM power package...
    Im realizing there are a number of way and combos you can do here.
    Any tips? anybody have advise on the subject?
    If I buy the kit, it comes all in one package, but is there a silver bullet here? Can I swap the cam out with a lumpier cam for more power? Is it really a HP killer to go with the heads with the smaller valves? The larger ones are 2.02"/1.60" but require more clearance than on stock pistons. The smaller ones suggested for stock are just under that really...
    Or is there a combo of heads, intake and cam I should get?
  2. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

    Seguin, TX
    If there is anything you learn about engines, it should be this: all internal combustion engines are an exercise in compromise. Simply put, as soon as you change one thing to increase it, you decrease another. A good example is removing the exhaust pipes from the manifolds. Sure, you get a big HP increase, but now the car's very slow off the line, even when you race the engine to peak the torque. Why? Because the big increase in HP gutted the torque. So engine builds often have to be worked out on paper, and on a dyno, to try to gain in both HP and torque to give the buyer a usable engine. So the only 'magic bullet' is to work with a machinist, to show what you want to do with your car, and what he can do to get you near those goals. Using new-tech heads, lightweight rotating assemblies and better fuel, ignition, intake and exhaust all more or less matched to each other, will get you the closest to what you need, let alone what you want.
  3. russosborne

    russosborne In Fourth Gear

    Glendale Arizona
    what is a 351 mild cam? You need to know what the specs are so you can have an idea of what to do.
  4. Johnnycoast

    Johnnycoast In Second Gear

    Good sage advise. True in most things engineering or mechanical, that when you make advances in one direction you move away from another advantage.
    Also good advice to work with a machine shop/mechanic. I called the shop who rebuilt my motor to find out what they ment bout "351mild cam". And he said he can look it up as they keep all the records, let's see what they say when he calls back. His quick advise was to caution against too low cc chambers (like 52 cc) as the motor may exhibit per-ignition or detonation and burn piston, as the pistons that are on there are flat top replacements, ie stock replacements...
    I do have some good mechanics (professional mechanics) who are friends in my corner. so I feel like if I can put new heads on myself, or swap the cam, I can call them for advise instead of watching a bunch of you tube videos.
  5. colnago

    colnago In Maximum Overdrive

    I agree with the above. On my truck group, I asked about input manifolds once, and basically learned that you can't just look at the intake manifold as if it works alone. Everything works together. Yes, you can see a difference if you change one component, but you need to look at all of the components and how they complement each other. You said that you want higher compression. Static or dynamic? If dynamic, you need to look at the cam profile as well. When does the intake valve close? What kind of overlap do the intake-exhaust valves have? Are you using the stock 1.6 ratio rocker arms, or are you using 1.7? Have you done any porting work? Are you using the stock exhaust manifolds, or headers? The engine has to breathe, too, not just compress.

    I'm at the beginning of a rebuild. My machinist set me up with a set of '66 heads from a 289, so I will have smaller combustion chambers as well. He said that I might want to go with dished pistons to lower the compression ratio. But along with those smaller chambers, I also have smaller ports and smaller valves. I'll be getting the block, crank, and connecting rods back from him next week, then I can start running some numbers. I'm not looking for burning rubber at the stoplight. I'm more interested in longevity and reliability. But we all want something different from our rides. Look at the whole, not just a part of it. Just my two cents.

    cbolt likes this.
  6. RancheroRandy

    RancheroRandy In Overdrive

    I have done a ton of research and the heads I plan on purchasing for the next step in HP/useable torque (heads, cam, tri-Ys instead of my shorties) are these: but I may go whole hog and stroke it out to a 347 esp. if I have to fly cut the pistons for the valve size. If you have an automatic with a stock converter you will, most likely, be needing a higher stall converter depending on the cam profile and/or change in rear end ratio...yes, costs pile-up fast! From talking with some engine builders these heads work the best "out of the box" because they have been in-house machined. Others not so much...

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