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my idea of the "ultimate" SBC

Discussion in 'The Garage' started by SICNICK, Mar 2, 2006.

  1. SICNICK

    SICNICK Registered Member

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    Alright guys, my truck has a 305 in it now and im planning on building the "ultimate" 350 this coming summer, Ive got a shop and a buddy who has built a few small blocks willing to help me, He has already found me a solid rebuildable core, and ordered me a master rebuild kit off of ebay. What little variables, like cam, porting, carb etc. would you reccomend for...
    The MOST reliable and economical small block (I will be driving this truck in between CO and Socal atleast 4 times a year) Obviously im not worried about huge power maybe 200-250 hp would be enough. What would you guys think would be the hot setup. BTW im pretty set on buildin the SBC since he already has the block and rebuild kit. 15+ MPG would be awesome and the ability to get 100,000 solid miles, What do y'all think? I got an SM465 and will be runnin 35-36's. What ratio even Thanks for the info:thumbsup:
     
  2. beater_k20

    beater_k20 Banned

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    the cam and gears are really going depend on the compression ratio of the engine. personally, i would find a cam that makes good power at cruise RPM, adjust CR accordingly.

    just based on trans, tire size and the fact that you are going to be driving it long distances, i'd say something along the lines of a 3.73 gear would be good. that would put your RPMs at about 2250-2350 at 65 mph. any lower, and the truck will probably be really sluggish around town.

    the key to a good reliable engine, is in the details, and in good parts selection.

    while an el cheapo $200 "master rebuild kit" may be a "good buy", i would be VERY cautious in buying one. you have no idea what quality of parts you are getting, because you dont generally know what brand they are. good fasteners are cheap insurance. if it has stock bolts in it, pitch em! no telling how many times they've been apart and back together, and how many miles are really on them.

    details you want to look into... make sure bearing clearances are where they need to be, piston to bore clearance, proper quench distance, cam timing, and rotating assembly balance are all critical in an engine that is expected to live a long healthy life. also, make sure the main journals on the block are true, as well as the deck surfaces on both the block and the head.
     
  3. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    For fuel mileage you will be hard pressed to get 15mpg.

    I would put a mild cam in the engine along with an aluminum intake like an Edelbrock performer. Easy with compression, since you will be driving it a lot you probably want to be able to run regular gas. I would go with 8.5:1 really, California gas isn't very good. I have to run 91 octane in my K5 that has a 406 with 9.2:1, which is not that high. Granted, it is a 400 and usually is more picky with octane and compression than a 350 due to warmer cylinder temps, but they aren't that different. 8.5:1 should be safe with california regular.

    I wouldn't run headers unless you want to spend a lot of money. They are louder and only give a few extra HP on a very mild near stock engine like you have in mind. Manifolds are less prone to blowing gaskets too, as reliability is a big factor with this vehicle obviously from the long distances that will be traveled through desert, mountain, and other bare terrain from California to CO.

    Cam, intake, nice quiet but good flowing exhaust, and a good carb is my vote. Will be noticeably more peppy than a stock 350 and have the best potential for a fuel mileage gain.
     
  4. roadnotca

    roadnotca 3/4 ton status

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    GM Goodwrench 10067353 for $1360.00 delivered (Jeg's), arrives in a few days, does exactly what you're looking for.
    Oh Shnap!:haha:
     
  5. TrcksR4ME

    TrcksR4ME 1/2 ton status

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    I was thinking the same thing when he said 200-250hp...except the GM Goodwrench is rated at 260, might be too high for him :grin:

    Seriously though, that seems like the best route for a stock replacement 350.
     
  6. PhoenixZorn

    PhoenixZorn 1/2 ton status

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    If you want 200-250hp, you are best off with a stock 350 out of another truck. I think the ULTIMATE Small Block GM motor is an Olds Rocket 350 bored and stroked to 472cu in... which has been done only by John Ligenfelter or however it is spelled... Granted the motor will cost you a good 20-30 grand, but you'll have the biggest small block in the world.

    Imagine 1200hp supercharged with all custom parts, and up to 1700hp with the bottle, all in a SBC package...
     
  7. Chevy305

    Chevy305 6 Lug 14bsf Status Premium Member GMOTM Winner

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    I disagree, headers can give you better gas milage. The only thing is that you need ones with the thickest flanges available to be sure they don't leak and make sure they are coated to last 10 times longer than paint. This why I like Doug Thorleys. They have the Tri-Y design that is supposed to give you the power really where you need it in the mid range and they are supposed to be more efficinent than the normal full length headers.
     
  8. SICNICK

    SICNICK Registered Member

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    great replys guys, although I would like to have the satisfaction of building my own motor. As well as saving a few bones, thats why I'd skip the Goodwrench motor. I could use more than 250 hp but mileage is my main goal.
     
  9. CyberSniper

    CyberSniper 1/2 ton status Premium Member

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  10. dyeager535

    dyeager535 1 ton status Premium Member

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    If you go with a mild cam, I'd also suggest getting a set of Vortecs.

    As long as you stay within the power range you state you want, they would probably be a very good fit for your motor. Need to make sure the cam company agrees on the stock Vortec valve springs, but that would be your only issue.

    Carbed Vortec intake, centerbolt valve covers, some cheap GM rail rockers, it would be no less reliable than the stock GM Vortec upper end, and work a whole lot better than any of the used heads you'd likely come across. It would also allow you to be a bit more flexible with compression.

    This of course assuming you don't have visual emissions testing, as the Vortecs aren't real EGR friendly.
     
  11. u2slow

    u2slow 1/2 ton status

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    IMO, 'ultimate' SBCs have at least 400ci. ;)
     
  12. dyeager535

    dyeager535 1 ton status Premium Member

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    Once you've had large displacement, you can't go back! :)

    But with a stated goal of at least 15MPG, the smallest displacement you can get away with and still be happy is going to be the easiest way to reach that.

    350 really is about the ideal compromise between efficiency, reliability and power. Not as much power as the larger displacement engines obviously, but (theoretically) better economy. With 350 and 305 rigs netting almost identical mileage (from personal experience, as well as most here that have done that swap) the supposed penalty from the 45CI increase in size doesn't seem to matter.

    Making sure the truck is as light as possible also helps, but you can only lighten so much, depending on what you need on the truck.
     
  13. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    That is what I did... well going to put on hopefully sunday...

    I was going to go with a more than mild cam but found a few things.. I dont know much about motors.... however....

    I bought a set of vortec heads off of a 1996 chevy tahoe in great shape (50k miles) from a member over at njfourwheelers.com for $200. Went and picked them up :wink1:


    so then I was looking at intakes... did tons of searching and on jegs and summit the edlebrock performer (forget if that is the torque one or was it torquer ii???) anyway that intake was $245!!!!!!! some googleing and I found a weiland (sp?) dual plane vortec intake for $120 to my door :bow:

    so im up to $320

    so now a cam... my 1991 caprice police motor is a roller cam... frickers are $245 from summit or jeggs.... so I called them and they recommended the comp cams xtreme 4x4 cam....

    now the stock springs on vortecs are said to be good to .480" lift as per both jeggs and summit.... the guy i bought the heads from said they ran a .610" lift on stock vortecs and never had a problem (only blew the motor due to NOS :haha: )

    so I was looking at the .474" lift cam.... desktop dyno 2003 (not accurate but close) I put my motor together stock and came up almost on the nail.... 195hp/295lb-ft torque....

    then added my headers, carb, new intake, vortecs, cam and came up with
    355hp/485lb-ft torque....
    so I was going to do that, however I noticed the cam was a 1200-5500rpm.... which I like mud and trails so WOT is not uncommon.. however if I crawl into some goo then nail it.. I want power right off the start....
    so the comp cams cam I went with was .457" (i think)... the summit guy said that that cam will be nicer to my stock springs and also my rpm's are now idle-5000... Just where I want them!!!!!! :wink1:
    these put desktop dyno to
    325hp/455lb-ft torque which to me is still good.... I know it isnt accurate so will dyno this summer :D

    $570 roughly to add power to my motor... still need gaskets but going to pick them up this weekend...

    cheap rebuild = no
    more power = yes
    radical setup = no so hopefully will get me better gas mileage...
    right now my hp sucks and I have to floor it EVERYWHERE!!!! plus I cannot keep up with say a stock jeep grand cherokee from a red light....I know this isnt a race car but would be nice to have more power.... I am running 4.56's and dont need to go lower.... I can turn the hell out of my tires off road.... so that aint no biggie... however with the added hp I should be able to use less right foot to get the truck rolling.....
     
  14. darkshadow

    darkshadow 1 ton status

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    jay lenos show got a new not yet avalable 42(5?) twin torbo small block from GMM that was said to put out over 1000hp, sounds like some compation.
     
  15. dyeager535

    dyeager535 1 ton status Premium Member

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    My super mild crane roller cam exceeded the spring pressure that the Vortec springs are built for, but as long as the poster stays away from the aggressive ramp roller cams run, (so using a flat tappet hydraulic cam) and anything under about .450" valve lift, he should be fine.

    http://popularhotrodding.com/enginemasters/articles/hardcore/0511phr_vortec/

    4th caption down on the left side of the pictures states .460" max lift, I tend to believe that more than any other numbers I've seen quoted, since it matches my experience. I measured mine with the lift at just over .450", and if I were racing, I would have had to change the locks. There just isn't enough clearance for safe operation with more lift.
     
    Last edited: Mar 3, 2006
  16. 1985_K5_Silverado

    1985_K5_Silverado 1/2 ton status

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    That's definitely the biggest sign that you need more muscle. I'm not talking about the stoplight gran prix stuff or to beat the other guy to the 2-into-1, but things like having to smash the pedal into the floor just to smoothly merge into fast traffic or not being sure you have enough power to pull out and take a quick left into a gap in traffic. Or those "weave lanes" that are a combo on-off ramp kind of area, not being confident that you can get out there without making other drivers have to hit their brakes to adjust for you.

    That's a terrible feeling when you're behind the wheel. I've driven a few ~100hp low-end, no-power econoboxes like that, and it just sucks when you put your foot to the floor, and there's just nothing there, not even with a downshift to get the revs up. I feel unsafe when I wind up driving a vehicle that doesn't even have enough power to get out of the way of traffic. :(
     
  17. Blue85

    Blue85 Troll Premium Member

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  18. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    On a stock motor I don't think headers are worth much at all. We've had three GM vehicles with headers. A stock 350 K20, no mileage gain or power. A stock 454 C30 dually, no mileage or power gain that could be felt. The only motor was my mildly built 406. I did feel a SLIGHT gain in acceleration under normal throttle after headers. I mainly credit it to the large displacement in a small block design (more restriction with 400ci's with the same head of other smaller SBC's) and a Comp Cam and higher compression.

    On a stock motor I wouldn't put headers on, I just don't think it's worth 300-450 bucks for nearly no gain in anything.
     
  19. PhoenixZorn

    PhoenixZorn 1/2 ton status

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    I learned of a race block today that starts out at 502cu in... and it's a small block. =)
     
  20. DieselDan

    DieselDan 1/2 ton status

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    How 'bout the "ultimate 4X4 small block" :

    350 or 383 cu
    mild hydraulic roller cam (more for off idle response)
    as much compression as you can get away with on 89 octane
    Vortec heads
    TPI intake (SDPC to fit the Vortec)
    Tri Y headers

    I'ld be looking for BIG torque numbers, alot of throttle response and a pretty wide power band (to clean the tread :haha: ) Did I forget anything?
     

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