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350 rebuild ideas..

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by ftn96, Jan 3, 2001.

  1. ftn96

    ftn96 1/2 ton status

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    I need some help with planning for my 350 rebuild. I want to get the most power for the buck. While keeping it smog legal and run on regular gas. And keeping it close to $1000. What all can I do or buy that will do this and keep me below 9.5:1??

    P.S. I dont know jack about all the heads and piston sizes, intake,exhaust chambers yada yada yada....

    Need help.

    Will work for parts, beer and sex.
    90 Jimi,350/700R4/241/10bolts/3.73's/33's/4"
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  2. kumma

    kumma 1/2 ton status

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    Well all i can offer is that you should look for torque instead of top horsepower. Check out issues of hot rod, car craft etc they have stuff like this all the time. There was an article in January 2001 hot rod for a stroked 350 - brought it out to 383ci i think they spent $1300 or so. Good luck.

    [​IMG]
     
  3. LittlePig

    LittlePig 1/2 ton status

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    Doing a 383 comes immediately to mind. It should stil be smog-legal, and will produce a decent horsepower/torque boost. The parts are easy: Crank from a Chevy 400 including balancer and tranny flexplate, .030 overbore pistons, some minor machining of the block, and VOILA! Instant stronger engine using all-GM parts. Get a decent rv or 4x4 cam for $100 and leave the carb stock. Headers can be had cheaply that do not affect smog-legality either. Good luck.

    Email: xiaozhu@my-deja.com
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  4. Andreas

    Andreas 1/2 ton status

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    In addition to Little pigs answer you have to grind the 400 crank to 350 specs. A 400 crank is 2.65" while a 350 crank is 2.45" if I remember correctly. Next up is connectingrods. You wanna keep the short 400 rods or do you wanna use 350 rods? New pistons either way. Not to mention rebalance costs.
    I don´t know if your engine is carbed of fuel injected? A new cam is defenitly most bang for the buck. Comp cams has good grinds. Check out the Xtreme 4x4 series. The smaller grinds should keep it smog-legal.
    Then there´s the usual bolt-ons like headers, 1.6 ratio roller tip rockerarms etc.
    Please give some more specs on your current setup.

    /Andreas

    406cui of pure sh*t[​IMG]
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  5. Butch

    Butch 1/2 ton status

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    My motor runs about 9.5to 1and runs on mid-grade alot better than on regular. I have a 350 bored .030 over, flat top 4 valve releaf pistons 76CC heads and mellings MTC1 cam shaft made for torque. It has awesome low end power, but the cam runs out of juice at about 4200 RPM's. If you run around town and play in the woods I would recommend this type of set up if you are a high speed interstate guy you might want a different cam shaft. I passed emissions in CO no problem. Good luck

    I thought I was wrong once,
    but I was mistaken
     
  6. LittlePig

    LittlePig 1/2 ton status

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    Andreas, I forgot about having the crank reground. However, that is not terribly expensive, since many reuilds have the crank reground anyway. The difference, as you say, is having the main bearing surfaces ground down 2 tenths of an inch. I do not recall any need for rebalancing costs, as the whole assembly is balanced by the shop anyway when they assemble it, whether it is a 350 or a 383 build (or anything else). The gross balancing is handled by the harmonic balancer anyway, as the 400 small blocks were all externally balanced. If you are a little more flush with cash, you can get custom cranks that are essentially 350 cranks with longer throws, so you don't lose any of the bearing surface (some people complain about the amount milled off because you supposedly lose some of the hardening of the crank this way) and you don't have to deal with the external balancer. Anyway, just a thought.

    Email: xiaozhu@my-deja.com
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  7. Not to throw a monkey into the wrench but its (very) very hard to find a 400 crank or a complete 400 in the nashvile area where he lives.The best bet would be buy a new one from summit.Hes got a good set of heads for his application.
    I'ld call comp-cams and ask them what the best cam for your app would be,I've talked to them several times in the past building motors and they have always had good advice.If you go the 383 route you mite want to consider having another chip burnt for your app.
     
  8. Chili 87 K5

    Chili 87 K5 Registered Member

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    I had this same debate with myself about 6 months ago... but I needed more than just an upgrade! My crankshaft had broken, and I needed all new internal stuff anyway (162K miles)... and I had a definite cash-flow issue.
    So, I opted for a .030" cylinder overbore (costs the same as any other cylinder boring), an RV camshaft, new pistons, etc. I kept my old rods, but basically, the rods, block, heads, valves, and exterior fittings are all that's original. The whole mess cost me about $700. This is my daily driver, and I did all the work myself. It's great if you can borrow the cherry-picker and engine stand from a chum who's not using them.
    I also added a 1" thick spacer under the fuel-injection unit. I made this critter out of $5 worth of aluminum stock from a local recycle place. This thing costs about $80 in catalogs, and is supposed to increase low-end HP and response (I believe that it basically increases the volume of the intake manifold. So, if you want to run a bigger engine (like a 350 overbored, like mine, or a 383 stroker), you can maintain aggressive intake vaccuum.
    Bang-for-the-buck, go for a new camshaft (get new lifters, too!). The cam is basically a solid-state "program" of how your engine performs, and is the key to making the most of what you've got.
    If you want to go with bigger displacement, I think the 383 stroker is the hot tip.

    Chenk out the kits (esp. the Budget 383!) at: http://www.speedomotive.com/

    Good luck!
    Chili
     
  9. Andreas

    Andreas 1/2 ton status

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    Little pig, the balance-thing came to mind when I thought of new pistons, which will be needed if he change stroke and/or change conrods.
    I´m by no means any expert on this but I´m rebuilding an engine myself. I have a sb400 bored .030 shortblock and a stock 350, complete but needs to be rebuilt too. So I´m toying of building a 377 or just instal the 350 rods in the 400 and keep it a 406 (wow, lot´s of numbers here[​IMG])

    /Andreas

    406cui of pure sh*t[​IMG]
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  10. ftn96

    ftn96 1/2 ton status

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    Im basically looking at the 383 with and rv cam and flat top pistons and some mild heads like I have, I think they are 194 202 heads. Im just worried about the computer. Like how much is it going to cost to get a new chip made? I have talked to summit, and they recommended a cam for my application. I cant remember which one it was, I have it written down at work. By the way Im running the stock Throttle body. I have heard about using the spacers, but my dad was telling me thatI would have to do some tinkering with the timing advance or something like that to get it to work. My only other question is that I have a block sitting in my garage now, thats already 30 over, but needs to be machined, so I have 40, but the only thing is that it is a 2 bolt main, and the one in the truck now is a 4 bolt. And I'd like to use the 4 bolt for obvious reasons, but it would be much easier for me to rebuild the 2 bolt one and just swap them out when the new one is ready. For torque daily driving weekend applications, do you all think the 2 bolt should be addicuate?

    Will work for parts, beer and sex.
    90 Jimi,350/700R4/241/10bolts/3.73's/33's/4"
    <A target="_blank" HREF=http://mccordhouse.freeservers.com>http://mccordhouse.freeservers.com</A>
     
  11. TX Mudder

    TX Mudder 1/2 ton status

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    I have the same problem. I have a 2bolt block in the bed of my truck and a 4 bolt that's currently in the truck.
    I asked around and I'm told it will work fine for a 383 buildup, cast crank.
    -- Mike
     
  12. Andreas

    Andreas 1/2 ton status

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    Yessir! A 2-bolt block will hold together just fine up to 450-500 hp, then you might wanna consider a 4-bolt. Even BDS, the company who makes blowers, thinks 2 bolt blocks are OK if you´re not charging that much. So, for a mild performance engine a 2 bolt should be just fine, the stock crank too.

    About advancing the timing. IF you buy a spacer to put under that TBI you´re making it a bit easier for the cylinders to draw their share of air/fuel in the plenum. You will get better cylinderfill i.e a "bigger" charge. This is all good! Now, to burn this bigger charge the spark from the plug must be allowed to ignite a little earlier. Makes sense, doesn´t it?[​IMG].

    /Andreas

    406cui of pure sh*t[​IMG]
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  13. ftn96

    ftn96 1/2 ton status

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    Amen Brothern'!!!!!!!! Thatnks for helping me twist my own arm.
    I'd still like to know an average cost for getting a new computer chip burned.

    Will work for parts, beer and sex.
    90 Jimi,350/700R4/241/10bolts/3.73's/33's/4"
    <A target="_blank" HREF=http://mccordhouse.freeservers.com>http://mccordhouse.freeservers.com</A>
     
  14. Andreas

    Andreas 1/2 ton status

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    Sorry, can´t help you with that one, I like ordinary carbs......well....errr...[​IMG].

    /Andreas

    406cui of pure sh*t[​IMG]
    <A target="_blank" HREF=http://hem.passagen.se/znus/>http://hem.passagen.se/znus/</A>
     
  15. ftn96

    ftn96 1/2 ton status

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    So, do I need to get flat top pistons, or what? If so What brand? I've seen some for 79 each and some for 19.99 each.
    And when you by a new cam, can you get the retainers, spings. lifters, rockers and all that jazz to go with the cam? The heads I have are some old little better than stock heads that need to be cleaned up and reworked. So I'll need to replace all the guts. Need some guidance here. My uncle says they have 194 intake valves and 202 exhuast valves. Or visa versa. Will I need to get new valves too.?

    Will work for parts, beer and sex.
    90 Jimi,350/700R4/241/10bolts/3.73's/33's/4"
    <A target="_blank" HREF=http://mccordhouse.freeservers.com>http://mccordhouse.freeservers.com</A>
     
  16. JimmyDie6.2

    JimmyDie6.2 1/2 ton status

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    2.02 intake or 1.94 intake and 1.50 or 1.60 exhaust. If they are stock truck heads, your probably 1.94 1.50, which is fine. There are other small sizes. you only need big valves like the 2.02s for high rpms like 6000 or more. Your building a truck motor, not a race motor, so keep the valves small and the lift in the cam high, and the cam duration short. Go with the 383 kit, and have it balanced, just because flywheels and dampers balance an engine dosen't mean the rotating assembly is balanced. you will get tens of thousands of miles more with a balanced motor as opposed to an engine that just has the crank pistons and rods jammed in there. A balancing job should cost, between $100 and $150. or just tell them to balance the kit when you buy it. Avoid a 377 in your truck, they are high revving motors that don't make proper power until 4000 and higher rpms, and a properly built one can withstand 9000 rpm shifts. A 377 is a good motor for a vega with a 4speed and 5:13 gears. you want the stroke of the 400 crank not the bore of a 400 block...............js
     
  17. ftn96

    ftn96 1/2 ton status

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    Yeah, these heads came off the same 2 bolt block, and at the time it was built for a fast car. I'm just hoping that they can be re-used for my application. What are the best pistons for my application? I am assuming that the domed ones will create more compression, so Im guessing that I'd need flat tops.

    Will work for parts, beer and sex.
    90 Jimi,350/700R4/241/10bolts/3.73's/33's/4"
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  18. Cmoe

    Cmoe 1/2 ton status

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    Besides having the 400 crank ground you'll also have to do some mill on the Block to get clearence for the rotation of the crank.... the piston rod bolts hit the block inner wall..... Remember that you may need to spend more money for quality work and parts, but you want the motor to last and produce the power over years of use...Make sure the your block is flat and true befor you spend a lot of money putting togather the motor.... Also have the block boild to clean the water jets......Rework the heads at this time is good also.... I would also recommend replacing your radiator or having it rodded since your engine is beening redone....

    C'moe

    <font color=black>the blazer is "Back in Black"
     

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