How much HP would heads alone add?

Discussion in 'Engine Topic' started by Crowsville, May 24, 2013.

  1. Crowsville

    Crowsville Member

    87
    0
    Jan 13, 2013
    New York, New York
    I'll be honest and say that I'm a newbie. I was sitting down and thinking of this and I couldn't have thought of a better place to get an answer to this question. I have a 350 on my 81 camaro that I believe came off of an 83 Chevy Pick up. I've done some research and what I've found is that these 350s produce something around 160 HP.

    I continued to do some reading and found out that the main reason that these motors produce such little HP is because of the EGR heads(smogger heads). When I got the car along with this motor it had a quadrajet that was shot so I took the easy fix and put on an edelbrock 1406. It ran well after that, but still didn't produce much power.

    I am 21 and I use this Camaro as a daily driver. I love the car and I simply cannot see myself driving anything else. This is why I am not really trying to build the motor to produce a ridiculous amount of HP and further worsen the MPG it has. I actually find the MPG at the moment very doable, but the little power it produces is quite embarrassing so I started to think of this and please feel free to throw in all the two cents you guys. I always throw around the saying,"If you're new to it, I'm true to it" to my friends and in comparison to many people on here I'm new to it and you're true to it! lol

    If I changed my stock heads with some from Summit/Jegs, along with the intake manifold and distributor would this make my HP climb to somewhere around 300 with the stock camshaft? Those are all simple bolt ons. The camshaft that's currently in the car I believe is the main contributor to the MPG my vehicle is producing... being that it's a truck motor wouldn't it be a better camshaft than lets say a car that had a 350 in that same year range?

    Am I correct in this thinking and if I am, what is it you guys recommend that I use as a replacement in cylinder heads, the intake, and the distributor to go along with my stock motor and 1406 edelbrock carb. I am sure that at this point a lot of you guys are sighing and saying it would be better to do x y and z, but the key thing that I want you guys to remember is that this is my daily driver and I don't want to kill my pockets here.. I just want to enjoy the power of a "muscle car". My motor at this point is a joke. :(
     
  2. night rider

    night rider Veteran Member

    6,401
    3
    Aug 6, 2002
    Bremen, Ga
    The car and truck stock cams from the 80's are really close together and the truck cam is just a tad smaller IIRC.

    The best bang for the buck would be a set of stock used 1996-2000 vortec heads, edelbrock vortec performer intake, and a small 204/214*@.050" cam of what ever brand, along with a set of full lenght headers, and good aftermarket exhaust.

    If you shop wise, you can do all the above for $1,000 (or less).
     
  3. Thunderkyss

    Thunderkyss Veteran Member

    222
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    Sep 16, 2012
    Texas
    I feel your pain.

    But I guarantee you the biggest culprit to poor mpg is your transmission. Probably turning 2500 rpm @ 45mph. The faster that thing spins, the more gas you use.

    Then it's the carb. You're dumping gas into the intake at the farthest point possible from the combustion chamber. You've got fuel all over the plenum & runners that will never be turned into power.

    The biggest problem with smog heads, are the big combustion chambers, which kill your compression ratio, which also does no good for gas mileage.

    Heads are normally a big ticket item & most people perform the mods to support the heads first. It's all about getting air & fuel into & out of the engine. Upgrading the heads are going to help, but only as much as your intake, cam, rockers, & exhaust will allow.

    If you're making 160 hp out of a 350, you're looking at 45% efficeincy, lots of room to work with. A set of heads for your car will probably set you back $700. Your engine probably won't breath much better because of your cam, the smaller combustion chamber might bump your compression up a couple of points. You might get 20 hp or so.

    But, after that, you'll gain more power from future mods, intake, headers, cam than if you didn't.
     
  4. Crowsville

    Crowsville Member

    87
    0
    Jan 13, 2013
    New York, New York
    You just hit it on the nail, what I want to do to do is do a mod that I can continue to build on. Vortec Heads are a direct bolt on, as well as the intake manifold that goes along with it. I was all for it and ready to order a pair from summit for 300 each, but the problem is that apparently the rockers are not compatible. You need self aligning rocker arms and from I read that is not a walk in a park to do.

    I simply want something that I can bolt on for now and as I continue to grow with the car and develop into my career path continue to build on it seeing continual growth, you know? On paper I am a magician, but the more and more I talk about it it seems a lot more intricate than what I think. =|
     
  5. 76z28

    76z28 Veteran Member

    1,716
    3
    Jun 29, 2009
    bakersfield
    In all honesty I would find a set of corvette l98 aluminum 113 heads cheap, get a set of headers, intake manifold, and call it a day. While they aren't the BEST heads out there I've come to find they make a TON of down low torque and have extremely small combustion chambers so you would get a very good bump in compression.
    It wouldn't Kill your mpg, you would lighten up the car, and it would be a blast to drive!
    Votechs are good though and probably easier to find. My corvette actually had self aligning rockers stock so those are super easy to find. It also had guide plates which seemed redundant.
     
  6. hhott71

    hhott71 Veteran Member Lifetime Gold Member

    14,377
    7
    Mar 30, 2001
    Joplin Mo. 64801
    Heads alone, not much.
    Performance engines (cars) are a complimentary assembly of parts. Starting at the air filter and ending at the rear tires.
    You addressed the carb by putting on a simpler AFB. I assume a 4x3"drop base air filter too.
    Better heads with 65cc chanbers will add some flow, and badly needed compression.
    Use an intake that fits the heads. Vortecs, or 165cc Jegs/Summit, RHS, S/R Torquers ETC
    Dual exhaust, and headers will help.
    Better rearend gears are a big plus. 3.08, 3.23 or 3.42 will really help.
    An HEI that is truly adjustable on timing.
    The cam in an 81 and 83 are the same, truck or car. They suck.
    Get a cam with 204-210* Intake Duration. It can be a Mellings, Sealed Power, Elgin, Summit/Jegs ETC a name brand in that size is just a pretty box. Get new sealed power lifters and timing set.
    You will wake it up.
     
    Last edited: May 27, 2013
  7. 1sic80camaroz28

    1sic80camaroz28 Veteran Member

    183
    0
    Feb 9, 2013
    Kyle,TX
    About a year ago I went to the local junk yard and picked a set of vortec heads and a rockers and pushrods from a 97 silverado and paid less than a hundred dollars for everything. Granted I put the labor of removing all the parts to get the heads off. but was worth it in the end. If you do this make sure you get thevalve covers too as these are center bolt heads. Do this and a performer intake and compcam xe256 it should really make difference compared to what you have now and still give you some very decent MPG's.
     
  8. Crowsville

    Crowsville Member

    87
    0
    Jan 13, 2013
    New York, New York
    For the power I'm looking to obtain this is what I have gathered so far. Vortec Heads are the way to go. I really have to figure out how to install the rockers because I'm really short changing myself not installing these Vortec Heads for the amount I'm looking to spend. Add an intake manifold, a CAM!, an exhaust system and we're in business. lol You guys also mentioned the valve covers also don't interchange so I'd need to make sure I get those as well.

    As for everything else the reason I had this mindset was because back in 1970 the 350s then had so much more power. My 71 Buick had 230 HP with a 2 Barrel! I know Buick 350s are different and offer a ton more torque, but that's besides the point. When I sat down and thought about it what was a noticeable difference were the heads and intake.

    I figured that changing the heads, and intake alone would make it get to at least 250 HP with my 1406. Then I could do the exhaust system and maybe later down the road put in a cam and get mid 350 HP to 400 HP. I plan on going the whole 9 yards with it, but I want to portion the money I'm putting into it kind of you know.
     
  9. Damon

    Damon Veteran Member

    12,937
    21
    Nov 16, 2000
    Philly area
    Self-aligning rockers are no big deal. They were used on all 87-up "centerbolt valve cover" heads, including later Vortecs. You could get a set off just about anything in the junkyard if you're really bucks-down. They look just like earlier rockers except they have two "shoulders" in the pallet area to keep them centered on the valve stems.

    Since you plan on buying an intake anyway, an upgrade to Vortecs is a great idea, I think. You don't even need the "modified" ones for high lift and big cams. Just a set of stock ones along with the afore-mentioned self-aligning rockers and some gaskets is all you need (use factory Vortec-style gaskets to mount the intake to the heads- they work best, in my opinion).

    I don't think you're likely to hit 300HP with just the head upgrade on a stock (possibly high mileage) truck bottom end, but 250HP should be no problem even through stock manifolds if the exhaust is relatively free-flowing behind them. Headers and a good 2-1/4" dual exhaust and 275HP should come pretty easy. And remember you're going to get this with BETTER mileage (compression increase and the better Vortec chambers help with that) and BETTER drivability (ditto on the reasons). Plus an in-car head swap is pretty easy, an in-car cam swap not so much.
     
    Last edited: May 25, 2013
  10. SpeedAddict02

    SpeedAddict02 Veteran Member Lifetime Gold Member

    4,538
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    Dec 31, 2002
    Wallkill, N.Y.
    Jegs has a Vortec "kit" I plan on getting.. $890 plus the ride.. You get both heads, intake, gaskets & bolts.. Not a bad deal IMO for all new stuff.. Still limited on the cam size, but for a street motor should be fine. If you are looking for out-of-the-box, bolt on an go, this is a good deal, to me.

    Just need to check ebay, craigslist or find a junkyard for a pr of valve covers and the self-aligning rocker arms.. Can probably get all that in a junkyard (u-pull) for $20.. Tack on new valve cover gaskets.. New spark plugs, Carb base gasket, exhaust manifold gaskets, thermostat housing gasket, and you're done. I would figure you're into it for a grand, without touching the cam or anything else.

    You wanna do the cam, You can go with a Comp 268H ( .454" lift) or the XE256.. Cam, lifters, pushrods, cheapo "Z28" springs if you cant use what comes on the new vortecs( Someone else would have to chime in b/c I dunno), timing chain, and associated gaskets.. Tack on another $300.. And you can use your stock converter and gearing for the time being.

    Next upgrade I would look into is a new QuadraJet, tune your HEI's timing curve, then set of headers/exhaust. Then worry about converter/Gears..

    well on your way to a street screamer. Heads, intake, cam, exhaust, all gaskets, Should be doable with $1500 if you do the work yourself.

    That's the way I would do it. Hope this helps.
     

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