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best engine mods

Discussion in 'The Garage' started by ross'blazer, Feb 14, 2005.

  1. ross'blazer

    ross'blazer Newbie

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    can anyone tell me what mods i could do to get some more horsepower, and such for my 91 blazer. i have a 5.7 L 350 V8.
    i dont want anything that costs tons of money, any suggestions on the cheaper mods. i want to get lots of power, but not spend thousands of dollars.
     
    Last edited: Feb 14, 2005
  2. riggz

    riggz Registered Member

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    bore it, new cam, aftermarket fuel injection kit
     
  3. dirtwarrior17

    dirtwarrior17 Banned

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    Your options go as deep as your wallet with a 350... If its completly stock IMO you should start with a tbi and manifold upgrade along with a chip and see how you like the power. It should jump from 210 to around 250 with those three mods. A holley 670 cfm is a good choice for the tbi and it has large enough injectors to feed 400 hp (if you get the fuel pressure and chip right). You could also get a wilder cam, add some headers, exhaust, intake, adjustable fuel pressure regulator, bigger fuel pump.... the list goes on. What do you want to do with it? HOw much are you looking to spend? We could help you out alot more if you gave us some sort of spending limit and what you want to do to it.

    If you are willing to spend some serious $$ you could get a smaller cc, higher flowing head that will up your compression ratio and give you some serious hp and tq gains if the stock heads have farely big cc so you can go smaller. I think stock comp ratio is 8 or 8.5:1 and if it has something like 74cc or 76cc heads you could go to a 64cc or a 68cc head and bring it up to around 9- 10:1 although i don't know what the stock 91 heads are cc wise.
     
  4. sled_dog

    sled_dog 1 ton status

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    boring out your cylinders really does jack to add power. If you need to do it, do it, but if you just WANT to do it, its a waste. heads and camshaft will be quick ways to the best power out of the stock fuel injection system
     
  5. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Good thought . Boring really is only neccessary to clean up the bores , not boring gives you an extra rebuild later , and those 5 extra cubes aren't really missed :D
     
  6. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    I bet me going .030 on my 400 gained me about 3.5 HP....big whoop. :)
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    You aren't going to get "lots" of power without spending 1000's of dollars, thats just reality.

    You can swap to a big block, which won't cost THAT much, (still around $1000 depending on how lucky you get) but "lots" of power is a subjective term.

    Heads, cam, exhaust, chip work will net you some gains, and that will easily set you back $1000 after all is said and done. It's not likely to even be a 100HP difference though.

    Going with a larger motor is going to be your "cheapest" upgrade in power, but then again, with TBI, thats even more expense and complications.

    Edit: Yes, completely forgot about nitrous Thunder. No way you can get that much power for that cost with any other mods. Some inherent danger (to the engine), and not a "constant" source of power, but power to $$ spent ratio is unbeatable if it works for your application.
     
    Last edited: Feb 16, 2005
  8. Thunder

    Thunder 3/4 ton status

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    Lots of power for cheap. One word..... Nitrous! Works great till the bottle runs out. Or a piston melts.
    Other than nitrous there aint no way "to get lots of power, but not spend thousands of dollars."

    Now if you want to be more realistic in your expectations You can bolt on about 30- 40 HP for $300- $700 Depending on your exhaust system.
    The first thing you should do is Good exhaust. Performance mods are worthless without headers and good exhaust. It will also give the most bang for the buck performance wise.
    Then you have to mod the TB to get more flow out of it
    Go here:cfm-tech.com
    Lots of stuff there to modify your TB to get more power out of it.
    If that aint enough power you will have to spend more money becuz. Its Head$, Cam, Intake, and Chip time.
    Speed costs money. How fast do you want to go?
     
  9. dirtwarrior17

    dirtwarrior17 Banned

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    i spent roughly 1000 extra(high pressure pump, efi manifold, tbi, headers, k and n, adapters, higher stall converter, etc) on a motor that costed $1535 as a reman longblock, but had a cam, manifold, 10:1, camel humps, good rods, moly rings, and was bored. all that should get 130+ hp over the stock motor. Deals are everywhere.yeah, I took a chance and got lucky from buying off ebay but if you do your homework on the seller and try to get a hold of some people he has sold motors to you can get a good idea of what kind of seller he is. I am not condoning buying motors off ebay but it worked for me... I'm not even close to done with spending because of the tbi issues. Still need to burn a chip for another 400 bones.... performance= expensive and always will.

    i got away with a 340 hp smog legal efi motor for around 3 grand. I plan to put some vortecs on as soon as possible becuase of the no egr valve camels and they are old as f***. That would make another 35-40 hp . im planning on getting some cheap bare vortecs then having them ported and polished. I don't know the exact numbers but when the vortecs go on i should be somewhere around 370-380hp. for 3500 bucks, thats not bad...

    I'm not trying to convince yall that my rig will stomp on all of yours because i know it won't:surepal: :rotfl: :shame: :thumb:

    Just trying to help him get some cheap reliable hp.
     
  10. Z3PR

    Z3PR Banned

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    If you're on a bugjet like alot of us, a good set of headers and exhaust is a starting point. Or if it's a carb engine, a aftermarket intake manifold is a nice starting point too.
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    I'm not going to argue the old part, but you can't run EGR through the Vortecs either...still have to run external EGR.

    I hate shifting thread topics like this, but working Vortecs for power and abuse, you might as well get some better heads off the bat. Yes, $1000-1200 for a set of heads sounds expensive, but Vortec's will nickel and dime you to death. And the $300 TBI Vortec intake isn't even figured in with the nickels and dimes.
     
  12. sandawgk5

    sandawgk5 3/4 ton status

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    get a set of world torquers they have bigger valves, flow better accept centerbolt and regular valve covers, 50 state smog legal, screw in studs, and only about $100 more per set than crappy vortecs. Just my .02
     
  13. dyeager535

    dyeager535 1 ton status Premium Member

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    My problem with heads is that everyone seems to be fixated on flow.

    Vortecs have a lot more going for them than flow. (the fastburn chambers)

    I guess smog legal is smog legal, but an aftermarket head with screw in studs, guideplates (if you want, vs. the rail rockers vortecs take), exhaust crossover, "standard" intake pattern/intake ports, and a fast burn chamber would be exactly what I would be looking for.

    No exorbitant cost intake, less prone to detonation (more compression on same octane) no press in studs to worry about, no reason to change the springs, no COST to change the springs over since Vortec springs are special, no hassle with EGR, and so on.

    Not sure if such a head exists, but you can probably eliminate more than 50% of aftermarket heads based on the chamber design alone.
     
  14. dirtwarrior17

    dirtwarrior17 Banned

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    good point...I've never heard of anything besides external egr valves. I meant the camels were old and they don't have an egr port in the heads(at least from what i saw). I don't really know how the whole egr works when it comes to heads. I just noticed it when i glanced at a bored out stock manifold sitting on my floor.

    I wanted to get some vortecs becuase they make good power and i thought i could do it for cheap but it looks like i should go ahead and spend the big bucks(gonna be a while then) Is there any other head I could find in a junkyard that has fastburns and will increase hp and tq?

    If i end up spending a grand on good new heads its gonna be the aluminum darts or the world sportsman 2's
     
  15. dyeager535

    dyeager535 1 ton status Premium Member

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    Best junkyard head short of the Vortecs I'm going to suspect is the L98, at least for certain applications. Still missing out on the good chamber, but they can be worked good, flow ok as stock, and I believe aren't limited in valve size.

    You can get pro-built (pro-action? Can't keep track anymore) vortec replacement heads for the same cost as Vortecs (new) if you look. There are a lot of choices out there, but not much in the way of stock heads outside of the Vortecs and L98's that have much going for them in todays world, compared to aftermarket offerings. GM performance products has some heads out that are just killer looking, but I can't recall the name. I think they are a fairly new offering, but I'm sure they aren't cheap.

    External EGR doesn't mean the valve is hidden, just that the exhaust gas to operate the system comes from the exhaust manifold. Older heads (I thought all up to a point) had a passage that ran through the intake from head to head to warm up the carb/TBI, which was also used to feed EGR...so there were no EGR pipes or anything, you just bolted the EGR valve to the intake and that was it. Since Vortec heads don't have that "crossover", it has to be run from the exhaust through a seperate pipe.
     
  16. dirtwarrior17

    dirtwarrior17 Banned

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    sorry for the hijack but how can i do that now with the camels and headers?
     
  17. camok5

    camok5 1/2 ton status Premium Member

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    Has anyone done the 330hp gm engine with the cfm-tech kit, that sounds like a good deal to me and fairly simple, cheap too?
     
  18. dyeager535

    dyeager535 1 ton status Premium Member

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    Short answer is that you probably can't. The Vortec intakes, and the retrofit TPI/TBI intakes are set up with a port where the exhaust gas is fed in. A stock manifold that has the crossover won't have that feed port.

    Could probably work something out on an AL intake, drill into the crossover, then feed the EGR into the crossover from the exhaust, but thats my only idea.
     
  19. dirtwarrior17

    dirtwarrior17 Banned

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    Sounds like a deal but be prepared to spend 300 bucks on a manifold and another 800 or so on a chip and cfm tech stuff.

    still is a good deal when you compare it to others tho.
     
  20. dirtwarrior17

    dirtwarrior17 Banned

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    I am not completly sure whats on my holley projection manifold but looking at the stock one I have on my floor it needs an egr head. Since the holley is made for something like 64-86 heads it should be able to run egr off the exhaust right? where is the crossover supposed to be? the holley on my truck is an egr manifold but i forgot to look at it to see it the egr runs throught the heads or not.
     

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