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1990 Chevy Caprice 79 K10?

Discussion in 'Chevy Trucks' started by jrm123180, Nov 22, 2004.

  1. jrm123180

    jrm123180 Senior Member
    Messages: 156

    Plowing: 1990 Chevy Caprice to 79 K10?

    Would I be able to put a 305 from a 1990 chevy caprice into a 79 Chevy pickup? I know that the 305 should bolt right in. The 305 is a fuel injected engine, would there be a place to put a fuel pump, or can I get a fuel pump for this? Also, would the intake from a 350 carbureted engine fit on that engine?


    This is going into a 79 Chevy Truck K10
    Last edited: Nov 22, 2004
  2. Tarkus

    Tarkus PlowSite.com Addict
    Messages: 1,113

    It will bolt up but I would suggest you transfer TBI hardware as well because the 305 has a lot higher compression than a 79 350 and a knock sensor too and if you switched to a carb (350 manifold will fit) you may have to ****** the timing a good bit to keep knock out (you will have to use distributor out of 350 too if you go to a carb). TBI unit have fuel pump in tank and a 87 K10 had TBI so you could find the correct tank and other stuff in a bone yard to make this work. Also 88 thru 91 blazers and burbs have TBI and were same body style ad 87 and prior K10's so there is another source for everything except fuel tank itself to convert your truck to TBI.
  3. derekbroerse

    derekbroerse 2000 Club Member
    Messages: 2,377

    Having just done that (TBI motor in carbed truck) let me say this: Yes it works nicely (other than teething probs setting up for my stroker motor) but it is definately not a job for the weak at heart! You will need to swap the entire wiring harness under the dash and engine compartment (from the '87 donor) as well as figure out a way to mount the computer since the bracketry is spotwelded in from the factory (we did some fancy torch work but we had the whole truck gutted). Being that I used a 1991 Suburban nose, I can also tell you that the headlight connector on the bulkhead is a completely different shape so that needs to be changed as well if you use one of them for a donor.

    Have a look in the photos section to see just what you would be in for in my unfinished post:


    There is a photo of all the dash cluster wiring disassembled, not even including the computer wiring and such. Label-makers are our friends!

    ps. If you are planning on plowing with the truck this season, DON'T start on this kind of a swap NOW!

    The 305 will physically bolt into your truck with no problems. The 350 manifold will NOT directly bolt on to the TBI heads, as the center mounting holes are drilled on a different angle. You can butcher it to fit with a grinder (slot the hole) but the head of the bolt will never sit flat unless you cut a relief in the bolt hole but that makes the casting very thin and prone to cracking. Aftermarket intakes are available. Factory carb'd intakes for these are few and far between. Check late 80's boats with the Chevy motor as they came with the QJet on a cast iron manifold with the TBI heads. I did one in the summer for someone's boat. You could also swap heads to a set of carb'd heads to avoid the problem and you can set the compression ratio where you desire it... all carb'd parts will fit (once the heads are changed)

    As for the fuel pump, YOU will need to CHECK! In the late 80's, the motors had the mounting boss, but NOT ALL OF THEM HAD THE HOLE FOR THE PUSHROD MACHINED! ie: you could physically mount a pump but there would be no actuation. Not sure why this difference was (ie where it was cast etc.) but we never found the pattern--didn't really look that hard honestly.

    Also on that same note: MOST TBI CAMSHAFTS DO NOT HAVE THE LOBE FOR THE PUMP EITHER! Some of the earlier ones still do (I am speaking specifically of the hydraulic roller cam, don't know if they changed the flat-tappet cam or not never looked) but they are rather rare as we found when using them as regrind cores.
  4. Tarkus

    Tarkus PlowSite.com Addict
    Messages: 1,113

    I know intake will not bolt to vortec heads but I would have though that they would have bolted up to TBI heads. Strange!
  5. derekbroerse

    derekbroerse 2000 Club Member
    Messages: 2,377

    GM raised the plenum height to built more volume for under the TBI. As a result, there was no longer any room to fit tools on the bolts, so the angle was changed so sockets and such would clear again. It is the same pattern, just the middle two bolts on each side, when assembled, are pretty well vertical.

    As you know, the Vortec pattern is totally different... however, with an intake gasket 'template' and some very very careful drilling, they can be used with the old intake. The aftermarket versions of the heads (non-GM castings) sometimes have both patterns automatically.