Engine rebuild questions..

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by fjleiter, May 23, 2004.

  1. fjleiter

    fjleiter 1/2 ton status

    Feb 13, 2004
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    Palmyra, NY
    Engine in my 90 K5 is on it's last legs, note that it's my DD so I'm nursing it along right now... In the meantime I have been picking up parts for a new motor to swap in. Engine is a 350 Vin code K.

    I want to build basically a direct swap motor, something that won't freak out the computer and will pass emissions sniffer test.

    So far I have a rebuilt set of heads (duplicates to what are on the truck now). Picking up a 30 over block, duplicate of whats in it now (87-95 one piece rear main, VIN K block). Now for the questions...

    1) What compression ration can I run and not freak the computer (ie: what's the stock compression for a 1990 Vin K 350)

    2) Like to upgrade/replace some of the stuff and do the following replace the TBI with an aftermarket Holley TBI, Edelbrock Performer TBI intake, Performer Cam, Headers into a 3" single exhaust through a 3" high flow cat.

    Is this feasible while maintaining the computer and passing emissions?
  2. dyeager535

    dyeager535 1 ton status Premium Member

    Dec 13, 2000
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    Roy WA
    First off, to make some better power (and to be better compatible with the aftermarket TB I'm sure) you need to get better heads.

    I know you've already got a set, but if you can find a way, a better set of heads will make a world of difference.

    As far as I know, you can run any compression ratio you want, as long as the engine isn't pre-igniting, which will retard timing through the knock sensor. That said, with good heads, 9-9.5:1 should be possible on 87 octane.

    Main thing on the cam is tight lobe seperation, 112* is a good number. Around 110* you start running into problems. A stock roller cam setup would be a real nice addition, better than another flat tappet. Your block should be setup for it, perhaps have to tap the 3 holes, but any '87-up car should have a cam you need, until they went to LT/LS motors. I believe even the Vortec cams will work, but they are pretty mild cams by any stretch of the imagination.

    Shouldn't have to much problem keeping what you have planned on the computer, but for optimum emissions and power, you will need to either start burning your own chips, or get ahold of someone that will burn you chips until they are right. Not cheap if you pay someone else, at least from what I've seen.

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