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What can I do to a 305...

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Hathaway, Jun 3, 2001.

  1. Hathaway

    Hathaway 1/2 ton status

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    I've got the 305 in my '86 and its been running a tad rough lately. i'll be doing a tune up but while I'm at it I was trying to figure out just what all I can do to this engine to make it a bit better. I can't afford a 350, as much as I'd love one I just can't do it (heck can't really afford to do anything to the 305 just yet but like most of you I'm sure I like to plan stuff out way ahead of time [​IMG]). So what I was thinking was I could pull the 305, do a rebuild and have it bored and stroked. I could throw headers on it and probably do a dual straight pipe 2.5" exhaust.

    So if I get the 305 bored/stroked how big would it be? I've been told its can go as big as 347 but I've got no clue really about this stuff. And what would be involved with this? Would I need a new water pump/fuel pump/anything along those lines for the large cube engine? Thanks in advance for any advice.



    Dan, '86 K5, 5.0L v8, NP208, TH700R4, open 10bolts front and rear, 3.43gearing, K&N filter, 31x10.50R15 Trailhandlers
     
  2. Sparky87k5

    Sparky87k5 1/2 ton status

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    For what a "bored & stroked" 305 would cost you, a 350 would be cheaper. You already have the stroke of a 350 (3.48") but need to find a 350 block to drop your crank & rods into. Add new pistons & you are home, much less money then boring & stroking your 305. With a little work & a 400 block, you could have a 377!

    87 K5, D60 & 14FF, 5 sp & NP208 & 383 stroker. Build it Bulletproof and take it fishing!
     
  3. arq

    arq 1/2 ton status

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    You could postpone your exhaust for now. for the price of the headers you could pick up a rebuildable short block 350. price of taking it to the machine shop will almost be the same. Some of the SB350 kits are actually cheaper than the SB305, so you'll save some money in the long run and have a big smile on your face when you are done. Then you can slap in your 350 and sell/trade your complete rebuildable 305 for some headers.

    you really don't have to do much to a 350 to get a sh*tload of power out of it.

    ARQ.

    1-72 4x4 CST Blazer
    2-71 4x4 CST Blazer
     
  4. 1bad82k5

    1bad82k5 1/2 ton status

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    I would suggest building a 350. It would be cheaper, and you will never do enough mods on a 305 to make it equal to a 350 without spending a ton of cash. Just my thoughts.
    eric

    Hell, it don't really matter....it's just for my race car.
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    Yeah its really not worth "building up" the 305. I think maybe its PAW that is selling a 334 kit, (stroked 305) but the 305 is a pretty pathetic motor, only thing it has going for it is the 350 crank : )





    Dorian
    My tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
    No anti-theft measures on your truck? No pity when its stolen
     
  6. beater74

    beater74 1/2 ton status

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    fill it with concrete and sell as a boat anchor. 305's were one of the worst V8's ever made by chevy. I know this is not much help but keep it running as long as you can and save every penny so you can purchase a 350. GM sells a stock crate 350 for right around $1000. You end up spending more than $1000 but it's worth it.
     
  7. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Actually in my opinion the 307 was a crappier small block than the 305...but they're both anchor material.[​IMG]

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
     
  8. '73 K5

    '73 K5 1/2 ton status

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    Don't waste the money on a crap motor. Do things that would help now, but also help a 350 later. Like if you upgrade the ignition or exhaust. But DO NOT spend money on the actual 305 block or heads.

    '73 K5
    Chevy good...Ford bad
     
  9. Thunder

    Thunder 3/4 ton status

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    The best place for that 305 is the bone yard. 305s only have 2 bolt mains. They are a very weak engine espically in a truck. Get a 4 BOLT MAIN 350. you can get a rebuilt one from:<A target="_blank" HREF=http://www.rebuiltengines.com/>http://www.rebuiltengines.com/</A> for around $1500. or try Checker, Napa, Auto zone, ect.
    Check the want adds you can usually pick up a good running 350 out of a wrecked truck for around $500 or less.
     
  10. Hathaway

    Hathaway 1/2 ton status

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    Ok so the 305 is a waste of money.

    Some one was saying I could pick up a short block 350 and add the crank and rods and I'd be in business? So all I do is swap the parts from the 305 to the 350? Buy new pistons and its all good or what? Little more detail on that as the short blocks are around a grand around here.

    Dan, '86 K5, 5.0L v8, NP208, TH700R4, open 10bolts front and rear, 3.43gearing, K&N filter, 31x10.50R15 Trailhandlers
     
  11. ftn96

    ftn96 1/2 ton status

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    Use it as an anchor for your boat!!!!

    Steve Fox for President, 2004.
    Jimi Hendrix was re-incarnated in 1990 as my....JIMI
     
  12. Pugsley

    Pugsley 1/2 ton status

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    There's no point in keeping the 305. Checker/Shucks/Kragen advertises reman. 350 4 bolts for $795. I've seen short blocks in the range of $495. Jim Pace http://pugsley.coloradok5.com
     
  13. dyeager535

    dyeager535 1 ton status Premium Member

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    Actually, at least in some cases, the 305 and 350 used the same crank (at least they were always the same throw, some casting numbers were used in both 350's and 305's) so you could probably re-use that. Save you SOME money, not a whle lot though, a new crank is $200, having a machine shop fix a worn crank is about $100-150. (basically not worth buying new crank for a motor you aren't going to be extremely hard on)

    Not exactly sure why the 305 gets such a bad rap, only thing it doesn't have going for it is that there were no 4 bolt mains, the heads typically suck, and not enough cubic inches for a lot of people.

    Other than those points, there are plenty of trucks with 2 bolt main blocks in them, heads can be swapped, same crank throw as the 350, and basically the same design as other Chev Small Blocks. Plenty of people get 100K miles + out of them, myself included, so besides the cubic inch deficiency, everything else can be changed/corrected to make it a perfectly decent motor.

    However, I'd still say 350. More cubic inches will always win in the end, all else being equal.

    Dorian
    My tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
    No anti-theft measures on your truck? No pity when its stolen
     

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