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Hot Rods Motorheads how to combo you SBC for HP?

Discussion in 'The Hokey Ass Message Board' started by porkchop4464, Jun 2, 2016.

  1. porkchop4464
    Joined: Jan 20, 2009
    Posts: 880



    I know there are many combinations; in fact, hundreds over the years when it comes to building a SBC; but what are some of the actual numbers and combos you all used /came up with in the end, and with what horse results?

    I ask because my Mouse is really tired and old, so after this summer's shows, I am finally pulling the engine for a long needed rebuild.

    In the Eigtiees in my Model A five-window, I put together a 2 bolt main with 10 to 1 pistons and a 292 duration cam. It had a too crazy idle and a lot of snot, but the valves were all over the place and it was just finicky and unreliable; I def want something a little tamer and more reliable for this Dodge.

    The heads on this engine are the shitty 70s, 74 cc 194s (nothing special)which I will have rebuilt at our local machinist. He can also punch the block for me, so I was thinking 10 over on mains and rods and 30 on the cylinders

    I don't want anything that won't run on the highest pump gas.

    A tad under or over three hundred horse is more than enough for my 1600 pound pickup.

    Examples/ actual numbers /do/don'ts and dyno specs with said combinations?
  2. Rex_A_Lott
    Joined: Feb 5, 2007
    Posts: 1,155


    You need some real expectations of what you want it to do, how you want it to look, and how much money you're willing to spend, otherwise this thread will be all over the map.
    There are much better heads to use than the ones you have.
    I mostly want to see how this rolls out, who gives you good advice and who just spouts off bullshit they heard at the ice cream stand.
    Good Luck!
  3. oj
    Joined: Jul 27, 2008
    Posts: 6,457


    10:1 hyper-euretic (however thats spelled) pistons to give it some authority in it's thump; dart Iron eagle heads to let it breath and reliability; about a 280H cam (about a .440 lift) with a good intake, carb & ignition.
    Personally, I use the 300HP GM crate motor. I get them delivered for $2050, with warrenty. Its worth that to not have to deal with a machinest.
    lothiandon1940, H380 and mad mikey like this.
  4. squirrel
    Joined: Sep 23, 2004
    Posts: 56,037


    Don't get too hung up on numbers....except for the cam, which you figure out what you want by the RPM range you want to use the engine. That depends on transmission (including the torque converter, if it's an automatic) and rear gearing. The overbore and crank grinding just need to be done to whatever the next size is, if they actually need to be machined, which you can't tell without inspecting and measuring them.

    Heads are where power is, spend money there if you really want more power. A very mild 350 in a 1600 lb car will scoot no matter what.

  5. greg32
    Joined: Jun 21, 2007
    Posts: 2,231

    from Indiana

    Buy one of Edelbrocks kits. Performer or Performer RPM. Proven combo, easy to build, and you can shop for deals. Hard to beat unless your an engine guy.
    Jerrybigbird and mad mikey like this.
  6. aaggie
    Joined: Nov 21, 2009
    Posts: 2,530


    For your purpose it would be cost effective to buy a complete ZZ crate motor and drop it in and go. More than enough reliable power with a warranty.
  7. Speed Gems
    Joined: Jul 17, 2012
    Posts: 6,433

    Speed Gems

    You didn't say what engine you started off with. 283,327,350,etc.
  8. The first thing I would do is get rid of those lazy open chamber heads.

    I am guessing that you are using a 350 block correct? If you are building a 355 a set of flat top pistons zero decked, keep your quench to .040 (this is a magic beaner number), a 300/330 horse stock cam or a 350 horse 327 cam, don't touch the crank unless it needs it, balance the rotating assembly, and a single holley 600 on Weiand Stealth or edlbrock performer, about any distributer of your choice except a stock HEI should put you in the 300-350 horse range.

    Oh and don't just bore it, make sure the bore you are choosing will clean it up, usually on a stock bore old mill they will clean up @ .030 but I have had them need more then that and have found others that would clean up by just switching from cast to forged pistons and a honing to size/clearance.
  9. It is pretty hard to beat the GM crate engines. By the time you do all the machine work and buy the parts for your current tired engine, it will be close to same cost. Depends on how much machining is required. Since you are not building a race engine, the crate route gives you warranty and hassle-free.

    If you do rebuild your engine, you can customize the machining to match the parts for best performance. Your heads will never be that good, consider the Vortec heads as alternative. This will also need new intake for the bolt pattern. I assume your engine is a 350, so the good thing is parts are cheap.
  10. LMFAO

    read my signature line and ask yourself, where are the bellybutton guys when you need 'em.

    Sorry I just could not resist. mean-devil-smiley-emoticon.gif

    Actually if someone wanted to build a 300 horse motor the formula is sim0ple, they had a 300 horse option for the '69 Chevelle, I know where there is a long block that could be had for 200 dollars (he's asking 250), fresh top end needs inserts. That would be the simplest formula just buy stock parts for a 300 horse Chevelle or that long block and throw some inserts in it.

    Or they made a 330 horse 350 for the '71 Nova, again use stock replacement parts and you are well on your way.
    Mark Hinds likes this.
  11. good book here that shows how to combo gm parts to make what you are looking for. lot's of info.
    the writer, Dave Lewis built the motor in my car 327 block with 283 crank. DSCF2630.JPG DSCF4269.JPG
    kidcampbell71, 30tudor and swade41 like this.
  12. tfeverfred
    Joined: Nov 11, 2006
    Posts: 15,791

    Member Emeritus

  13. porkchop4464
    Joined: Jan 20, 2009
    Posts: 880


    Some more details: The car has 488 rear gears (locked spool) and a 5 speed manual Trans. I am gonna stick with the same heads, as I just can afford more than a quick rebuild. I will prob keep the rods in it and reuse the pushrods as well. New oil pump and I already have a gear drive on the timing I am keeping. Budget is key, but I still want to get the most I can.
  14. porkchop4464
    Joined: Jan 20, 2009
    Posts: 880


    Sorry, it's a 74, 350 four bolt main
  15. porkchop4464
    Joined: Jan 20, 2009
    Posts: 880


    I have heard the crate engines are really a great deal. But 2300 is a lot more than 12 hundred with me picking all my own parts.
  16. squirrel
    Joined: Sep 23, 2004
    Posts: 56,037


    If you do a little clean up porting on the heads, just smooth out the bowl to seat transition, and put flat top pistons in it, and a cam around 235 degrees at .050" lift, it should run pretty good. You'll notice the idle, but it won't be crazy. Make sure the valve springs match the cam, etc.
  17. porkchop4464
    Joined: Jan 20, 2009
    Posts: 880


    10 to 1 flat tops will run on pump gas, correct? Is there anyone out there with a car running ten to ones s that can comment.
  18. squirrel
    Joined: Sep 23, 2004
    Posts: 56,037


    Flat tops with those smog heads will run on pump gas. I had a smilar engine in my 39 chevy years ago, a bit less cam, it worked well.
  19. I am running more then 10:1on pump gas but my quench is tight and I am running aluminum heads, and some other stuff.

    If keep your quench pretty tight ( which you would have to do to make 10:1 with open chamber heads and flat tops), keep your engine pretty cool yes you should be able to pull it off but it's going to be marginal. You would be safer dropping your compression by .5, but that's your call.
  20. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 5,256

    from illinois

    If you're going to run anymore than 9.5 :1 , i'd say look at aluminum heads , they're damn near as cheap as rebuilding those boat anchors you have , plus, they perform..
    Look at competition products , you can't beat thier prices..
  21. indyjps
    Joined: Feb 21, 2007
    Posts: 5,377


    Change the heads, anything you throw at it will make more power.

    Ive run that comp 292 cam, bunch of duration with not enough lift. Sure made a lot of noise and ran hard in the narrow powerband. Ditch it.

    A very basic short block and good heads will get better results than the 70's smoggers and a high end short block.

    That said I've seen some very strong circle track engines running 882 smoggers with 2.02 valves and port work in iron head restricted classes (before vortecs). Your cam with 4.88 gears will be close to a circle track cam.
  22. lippy
    Joined: Sep 27, 2006
    Posts: 6,825

    from Ks

    4.88's with that engine with a hydraulic cam? So what are we talking, 55-5800 rpm? You better rethink those gears. Lippy
    gimpyshotrods likes this.
  23. maybe he's running 12.50x44x16 Super Swampers.LOL

    The truth is that it doesn't take much to build a 300 horse 350. I wouldn't do anything other then a stock rebuild.
  24. indyjps
    Joined: Feb 21, 2007
    Posts: 5,377


    Comp 292 in a sbc with ported bowtie heads that I had, ran up to 6500 shift point, 6800 in a few occasions. I changed to a cam with similar duration and more lift and made better power. I don't care for that particular cam but it would rev.
  25. porkchop4464
    Joined: Jan 20, 2009
    Posts: 880


    Nope, just 15 inch wheels. I know the 488s are low, but they were my choice and I was smiling while I setting up the dial indicator. Since she will be a coffee getter, I just want to put the hammer down and hold the hell on. I could care less about anything over 75 miles and hour. For this car it really is all about getting to 60 as fast as I possibly can.

    My Chevelle in high school had 88s with a 402 BB, and I used to bet kids they couldn't touch the windshield the first 5 seconds off of any green light in town. Won a few fins that way, as people who have never really experienced speed, and I mean real speed, scare easily. Oddly, these same folks very quickly learn to love the speed as well. Lastly, I am running a tunnel ram with twin 4s, so the low gears will give me a little leeway.
  26. porkchop4464
    Joined: Jan 20, 2009
    Posts: 880


  27. porkchop4464
    Joined: Jan 20, 2009
    Posts: 880


    Okay, so here is the numbers for the 290 horse engine above. 290 is plenty for me, and I am sure these are the same heads I have on this engine.
    • 8.5:1 compression ratio
    • 87 Octane recommended fuel
    • 4-bolt main caps
    • Provisions for both RH and LH oil dipstick
    • Contain a 2-piece rear main seal
    • .450" intake / .460" exhaust - cam lift
    • Cam duration @ .050": 222° intake / 222° exhaust
    • 112° lobe separation
    • .194" intake / 1.50" exhaust valves
    • 1.5:1 ratio rocker arms
    • Add an intake manifold, carburetor, ignition system, starter, balancer, and water pump
    • The best value crate engine in the GM Performance Parts lineup
  28. indyjps
    Joined: Feb 21, 2007
    Posts: 5,377


    If youre looking at crate engines, compare to this one, Jegs price is $2850, uses vortec heads.

    350 HO Base TECH SPECS:
    • Engine Type: Chevy Small-Block V-8
    • Displacement: 350ci
    • Bore x Stroke: 4.000'' x 3.480''
    • Block: Cast-iron with four-bolt main caps
    • Crankshaft: Nodular iron
    • Connecting Rods: Powdered metal steel
    • Pistons: Cast-aluminum
    • Camshaft Type: Hydraulic flat tappet
    • Camshaft Lift: .435'' intake / .460'' exhaust
    • Cylinder Heads: Vortec Iron; 64cc combustion chambers
    • Valve Size: 1.94'' intake / 1.50'' exhaust
    • Compression Ratio: 9.0:1 nominal
    • Rocker Arms: Stamped steel
    • Rocker Arm Ratio: 1.5:1
    • Flexplate: 12.750''
    • Recommended Fuel: Premium pump
    • Ignition Timing: 34° Total @ 4000 rpm
    • Maximum Recommended rpm: 5100
    • Balanced: External

    Bolt on takes it 377hp.

    I guess I misread the initial post. If 300 hp or so is sufficient, just rering and bearing your existing engine, valve job on the heads you have with about a .470 lift cam. 600 carb of your choice, dual plane intake and headers. Ive built this combo many times, decent idle with a little lope. The 4.88 gear kinda throws the deal off.
  29. I looked at the GM crate engines and the 1500. one and the 2100. one had all the same parts except the cam. so I bought the 1500. one and the cam for the 2100. one and swapped the cam. Saved almost 500. Get a good cam bolt kit when you're buying the parts. The ones in my motor sheered off before the torque setting was met. YMMV
  30. Old TFFdriver
    Joined: Jan 14, 2016
    Posts: 191

    Old TFFdriver
    from California

    This is how I combo my SBC ( or any other motor for that matter) ..,,for HORSEPOWER ..,

    I open my wallet and ask how fast do I want to go ? .., If I hear a echo .,,,

    Well .,,,,

    If a big wad of green jumps out ... Possibilities are endless ...,or until you hear a echo ....

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