pre '87 motor or post '87

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Blazer_Boy, Jul 31, 2001.

  1. Blazer_Boy

    Blazer_Boy 1/2 ton status

    Dec 16, 2000
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    Sioux City, IA, USA
    pre \'87 motor or post \'87

    The subject is pretty much the meat of the question but I suppose I can give one of my long and drawn out stories for your reading enjoyment. We have one 1982 K5 blazer with a dead stock crate motor with about 30,000 on it (mine). And a rotten, no good, stickin pain in the butt 1989 Jimmy (dads). Well actually it has a 6" lift w/33's and a clean body. The problem was that it blew a head gasket and my mom drove it back home from the grocery store a mile away that way. I laid my dads options out and told him we might get lucky and the bearings are still good and could just rebuild the top half. So he wanted to go cheap and rebuild the top half. I took a few days off doing the body work on mine and redid his motor. We had the heads planed and valves ground. I got it going and it was just running like a scalded dog. The exhaust sounded alot better because the valve job, had more power, and i was rather pleased with myself. Well about 40 miles after that it started to knock and had low pressure, bye bye rod bearings.

    I have to finish the body work on mine before college and can't get around to his. So he is hiring out to be done (real sharp mechanic, has his own shop, does all the work, and has been at it since 1957). To make things more interesting the guy that runs the place where the heads were machined scored a new vortec 350 and is selling for $600 (It was a dealer goof, a newer vehicle had a wierd noise so they pulled the motor for a new one and it turned out to be the transmission).

    Which brings me too my question, I could score my dads old motor for nothing. I'm looking for a motor to rebuild with some big mods. I like it because has a roller cam, the edelbrock port injection kit $1,000 less than the one for the pre '87 motor, and the vortec heads just drop right on with no drilling. I wanted to do my '82's crate motor with some ported heads and a big top end upgrade but I don't know if the bottom would be up to it and I don't feel like tearing into a low mile motor when I could sell it and score some cash.

    What do you think?

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  2. CaptCrunch

    CaptCrunch 1/2 ton status

    Feb 2, 2001
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    Re: pre \'87 motor or post \'87

    So is the motor in the 82 dead or what? Kinda confused but I'll assume you ment it is slow as a dawg and not DOA.

    The stock bottom end is gonna be up to about 400 horse... what exactly are your plans for this motor to be? If you go the Edelbrock MPI conversion route for $1200 or so then you will need to wire in the 87 and up computer, so all in all even if you went w/ the 87 up conversion it would still run you more for the wiring harness and computer. Also note that w/ this setup you would have a pretty limited head selection. You have the TBI heads... the new GM performance TBI HP heads, A few different TPI heads and the Edelbrock TBI style heads... If you run stock GM heads you will probably be looking at 300 hp tops unless you get them ported... maybe begger valves, etc. All in all both kits will cost about the same unless you can gut the computer and wiring from the Jimmy... which I would guess no.

    Ok enough of the FYI stuff... Here is my $.02 on this... if you have a crate bottom end w/ 30k us it! Most people way over estimate the power their engine is gonna make or does make, plus I am gonna ssume you aren't gonna be beating this engine up past 5,000 rpm, so you should be fine. Put the money into the cylinder heads and valvetrain. That is where your power is gonna be made... just watch the combustion chamber size... one too small will raise the compression and one too big will send it through the floor and make it a dog. Best bet is to find out your compression ratio and CC size on the crate head, then take it from there. Also you'll need to decide what you want to do induction wise. The Edelbrock conversion is nice, but for a pre 87 rig it is one expensive upgrade... I also really don't think converting to a TBI over a carb is worth the time and expense. You could bolt on a set of Vortech heads, Edelbrock perf intake, Edelbrock carb, and go roller valvetrain and make more then enough power on a fairly realistic budget. For about 700 less you could go the hydralic cam route and be still making lots of power. The vortechs will flow as good as any of the TBI heads mentioned and will also bump up the compression a little (which I'm better it is just the plain jane 8.5 to 1 compression crate motor... ut again check) which will help w/ the power and gas milage figure. Overall for an outlay of $1000 to $2000 you would have a sweet motor. You obviously would loose the perk of fuel injection for offroading angles, but I think that is a very minor drawback unless you are a dieharder.

    1987 Chevy K5 Blazer- 350 TBI
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