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Can an 88 350 be rebuilt to over 300 hp on the cheap?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by bigk, Feb 10, 2002.

  1. bigk

    bigk 1/2 ton status

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    Got a 160k 350 and was wondering how much it would cost to rebuild it and beef it to over 300 hp and close to 400 ft lb of torque? I've seen magazine articles on rebuild kits from Powerhouse that say you can do it for under a grand. Any experiences to share? How much more would it be to make it into a 383? We have a really good machine shop in the area that I've used in the past and was pleased. I'd like to save money anywhere I can, D60's and 42's ain't cheap. I do think I wouldn't mind splurging on a set of Vortec heads, though. Thanks.

    Karl
    Temporarily Unemployed Underwear Model
    87 3/4 ton
     
  2. RedDwarf

    RedDwarf 1/2 ton status

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    You can pick up a good bit of power just by ditching the smog crap and adding headers/exhaust.

    Then go with a performer manifold and good carb and flattops. A good camshaft will finnish getting you close to 300HP. Your torque will be more like 350 though.

    If you could snag some Vortec Heads for cheap, that will make the biggest difference. You need the right manifold to fit them though, so plan ahead.

    Good machine work is worth the extra $$$ as there is a lot of power to be had just by squaring everything up there.
     
  3. rockink5

    rockink5 1/2 ton status

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    should be no problem. I've got one in the works for a 79 2wheel project. works out to be about 375 and it should be mostly legal. definetly vortech heads. good bang for the buck
     
  4. wayne

    wayne 3/4 ton status

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    If you are building an 88 and planning to keep the FI you will need to get a chip burned for the puter for those kind of numbers most likely. Plus you will be limited on cam choise with the FI. The head swap would be a big gain but the drawback is the TBI intake for the Vortec heads is over $300.

    See <a target="_blank" href=http://coloradok5.com/gallery/Waynes-Toy>Project Mighty Mouse</a> here.
    <font color=blue>Wayne<font color=blue>
    <font color=blue>Happy Trails<font color=blue>
     
  5. 89GMCSuburban

    89GMCSuburban 1/2 ton status

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    This one place I saw has 350 crate motors, and on a TBI 350, with only a cam change, it went from 210 hp to 270 hp. Website is www.goautocenter.com Also, wayne, GM Performance parts offers a pair of Vortec heads drilled for the old style manifold bolt pattern for about $50 more so you can reuse your manifold.

    Red 1989 GMC Suburban SLE V1500 - TBI 350, 700R4 w/ shift kit, Quad-shock front, 31/10.50/15 Pro Comp MT, 4.10 gears, Duals off cat
     
  6. bigk

    bigk 1/2 ton status

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    That's nice to know about the new manifold. I guess you could use the Edelbrock Performer replacement then.

    Karl
    Temporarily Unemployed Underwear Model
    87 3/4 ton
     
  7. 89GMCSuburban

    89GMCSuburban 1/2 ton status

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    Yep, any manifold with the old 8 bolt pattern

    Red 1989 GMC Suburban SLE V1500 - TBI 350, 700R4 w/ shift kit, Quad-shock front, 31/10.50/15 Pro Comp MT, 4.10 gears, Duals off cat
     
  8. Thunder

    Thunder 3/4 ton status

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    If you want to keep your TBI. here's a couple of engines built for a TBI:<a target="_blank" href=http://www.sdpc2000.com/cart.asp?action=catalog_start&amp;catid=1577>SDPC TBI engines</a>
    judging from the cam specs a stock or aftermarket stage 1or 2 chip should run these.

    I dont think you will ever get close to 400 Ft lbs of torque out of a stock TBI.because of the limitations on how big of cam you can use
    You will have to go with a carb, good cam, vortec heads, ect. To get that kind of power/torque.

    <a target="_blank" href=http://coloradok5.com/gallery/Thunders-Blaze> Blazer pics</a>

    <font color=blue>Nevada... Where the pavement ends and the west begins
     
  9. Blazer_Boy

    Blazer_Boy 1/2 ton status

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    No 383 for you if you want to keep things on the cheap.

    The 383 kit from Northern Auto Parts is $370 without the crank. The crank for you would cost $260. That kit is ment for a pre '85 motor so the cost would be even higher for your late model. You also have to factor in the cost of getting bigger injectors and possible computer conflicts. If you keep it under 330hp, then it may be feasable. I got the 330 number from 4-wheel and off-road. They had a 383 with a big block Throttle Body and injectors that had some custom chip and bigger injectors would have been needed past 330hp. I'm just saying forget because its a confusing and expensive mess that requires a different damper and flexplate, and clearancing inside. Its a good motor, just not for your situation.

    Keep your 350 and get the comp cams model 12-249-4, its designed for work with the TBI engine. Then get the northern kit with fel-pro gaskets, clevite bearings, and comp cam upgrades. I'd skip on the hypereutectic pistons. A time bomb in my opnion. <a target="_blank" href=http://www.taperformance.com/hyperteu.htm>TA Parts </a> won't even sell the damn things. Some how I don't like pistons with extra sand added in my motor. All they are are pistons with extra silicon added which increases the hardness, and brittleness. When they go, they are more likely to shatter and destroy your motor. They push them as some modern miracle when in fact they've been around for some twenty years. They push them so much because the are so much easier to make. The hypereutectic pours easier and gives less of a reject rate, meaning more profit. They most more than straight cast because performance stuff is always supposed to cost a little more. A $1 or $2 more would look funny so they jack the pirice up. I didn't believe it myself because I listened to the hype. Try taking a cast piston and a hyper and hit them with a hammer, the hyper will shatter. Inside you'll see all the little holes in that is created when the extra silicon cools. I'm not saying the cast will hold up to more, but its nice to know it won't explode when it does go. Talk those who race, instead of read magazines and ads and you'll hear some interesting stuff. Go forged if you're going to be a real speed demon, which would be expensive and not necessary for your 300hp. Cast is good for low to mid performance.

    Anyways $360 for the kit. $450 for new vortec heads and $200 for the intake. The machining will vary I guess, maybe $200 to get everything ground and bored and to hot tank everything. Then a $100 for crap like engine paint, oil, plugs, ant-freeze, etc.

    $1,310 for that setup there. If you drop the heads and intake you'll save $650 but will have to add $100 more to the machine work because you're heads will need to be done. I'd go with $1,300 setup, 300hp easy and better componets.

    According to Engine Analyzer, that very motor I described would make 384 lb/ft of tq. and 332hp. Thats using tube headers, no accessories, and Big Block Throttle Body. In reality I'd probably say just barely over 300hp and around 360 lb/ft of tq.


    <a target="_blank" href=http://www.geocities.com/bigkern76>The Blazer Boy Page</a>
     
  10. bigk

    bigk 1/2 ton status

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    Thanks for the info, Jon. The heck of it is all that work gets me awfully close to a decent crate motor with a warranty. Maybe I should just think in that direction. Someday I'll have a toy to build a motor for, I'm dyin to do it just for the fun of it.

    Karl
    Temporarily Unemployed Underwear Model
    87 3/4 ton
     
  11. Blazer_Boy

    Blazer_Boy 1/2 ton status

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    You'll have to forgive my rant on the hypereutectic pistons. My machinist was pretty firm on that point and now I have to justfy my purchashing cast pistons, hehe. Actually I think you'd still be ahead of the game if you built it yourself. If you buy a GM Vortec crate, you're looking at $2,000 + $200 for the intake+ $100 core + shipping + computer compatible cam. I know that new motors aren't supposed to have cores but GM decided that this is the way its going to be now , unless you fork over your old motor. Sucks, huh? Just hang until your old 350 dies and you can easily justify a rebuild. It will mean more power at a cost less than a crate engine. If you get along with your machinist well enough, they may let you assemble it at there shop with a little a guidance. This way you can save a few dollars and learn something new.

    <a target="_blank" href=http://www.geocities.com/bigkern76>The Blazer Boy Page</a>
     
  12. CaptCrunch

    CaptCrunch 1/2 ton status

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    Well I guess since I have been researching this for about 8 month now I will voice my two cents. First off the SD motors. I question whether you can get those hp numbers using a stock chip and TBI unit. I just have a real hard time seeing stock FI stuff doing that. When I talked to their tech guys they basically ditched the question and wouldn't answer what rpm the numbers came at. Also notice the 9'6 compression ratio... a tad high if you want to run 87 on that setup IMO.

    I plan to run a holley TBI unit. These have 80 lb injectors and will flow about 700 cfm. Not sure on what heads I will run, but one thing is for sure, porting rules.No such thing as a drop on out of the box head IMO. cleaning them up will easily increase the 30 hp gain of the vortecs (Only difference netween those two SD motors) up to 40 or 45 hp. Also keep in mind how much rpm you want for the engine.

    I plan to do overkill to get my power. Holley TBI unit on top of a 400. 383's are nice, but I would only go with one if I could find a short block cheap or had no way to get a 400. I'm thinking some 882's ported up would give me the power or maybe a larger valved Camel hump or aftermarket head cast head down the road. I guess we will see.

    -Mikey
    1987 Chevy K5 Blazer- 350 TBI
    <a target="_blank" href=http://coloradok5.com/gallery/captcrunch>http://coloradok5.com/gallery/captcrunch</a>
     

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