GM crate engines?

Discussion in 'Engine Performance + Maintenance' started by big_mike, Jun 2, 2019.

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  1. big_mike

    big_mike I'm Awesome

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    Hey guys, anyone here used the GM replacement engine for the 96-98 full size trucks? I see they offer 2 different Vortec headed motors. One is listed as a standard replacement with 2 bolt mains while the other is listed as a HD version which comes with 4 bolt mains and I believe different hardened exhaust valve seats.

    This motor would be going in a daily driver with occasional towing. Question is should I just stick the stock 2 bolt replacement in or grab the HD? Looking for any feedback from anyone who has bought one of these and installed, hard to beat the price and 3yr 100,000mi warranty. Cheaper than I could rebuild the current motor once I add in machine shop costs.

    Here is a screen shot of the 2 motors, prices and descriptions. Just happens both are on sale right now.
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    Last edited: Jun 2, 2019
  2. Christian Steffen

    Christian Steffen I'm Awesome

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    IMO for $90 this is a no brainer.
     
  3. Gibson

    Gibson OBS Enthusiast

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    Yep,, you got that right.
    Someone correct me if I'am wrong, but IIRC the heads on the 4-bolt block also use rotators on both intake and exhaust,, and a windage tray under the intake manifold.
    Spend the extra bucks, the HD engine is better.
     
  4. Schurkey

    Schurkey I'm Awesome

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    Is the compression ratio the same? The HD TBI engine used lower compression.

    I'd also wonder about the cylinder head castings, the valve sizes and configuration, etc.

    What camshaft is used in the HD vs. the half-ton engine? Is it installed the same--not retarded or advanced?

    Does GM get picky about the warranty if the VIN doesn't match the "approved" application list?
     
  5. L31MaxExpress

    L31MaxExpress I'm Awesome

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    I have the 8800+ GVW engine in my 1/2 ton G1500 Express van. It broke a valve spring early in its life and GM warrentied it. It may have only been under GM parts warranty though. Regardless they pulled the valve cover and swapped it out with no cost to me since it was not deemed an installer error. It had 062 heads and the same cam as any Vortec 350. Same pistons and compression ratio as the 1/2 ton. It does not have rotators on the intake. It does have a single roller timing chain though. Also uses a different crank than the 1/2 ton. My stock 97 engine had 906s on it FWIW with the multi angle exhaust seat rather than the HD 1 angle seat. Really the only difference between the castings. The 062s had the single angle exhaust seats in the HD engine. I noticed a slight power loss but when those heads were flow tested the 906s smoked the Hecho en Mexico 062 crate engine heads in intake flow. I also used the upgrade spider which is only 22.1 lb/hr with the regulator at the stock pressure rather than the OEM 23.1 lb/hr spider. After I fixed the tune using the flow rate for an 03+ 4.3 it ran normal. The exhaust flow between casting was practically identical by 0.100" and the single angle only lacks slightly below that. Bone of that matters now since it has aluminum heads and a custom comp cam in it.
     
    Last edited: Jun 2, 2019
  6. big_mike

    big_mike I'm Awesome

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    All specs are identical according here to the information provided on SDPC site. Seems the only difference is the exhaust side of the heads, weather that’s one head casting now with 2 different exhaust seats or still 2 castings. Vins will almost definitely show the 2 bolt as the original motor since they are both K1500 series trucks. Just going off what I have read anyway.
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  7. likestrucks

    likestrucks Newbie

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    I had the HD 4 bolt crate put in my 98 k1500 back in 2012 at a GM dealer. It did not affect the warranty. For the extra $100 I wanted the extra piece of mind.

    The 4 bold HD engine came with the 906 casting vortec heads, they had some differences in the exhaust valve that made them more robust under sustained high heat heavy load applications. The 062 head on the 2 bolt LD engine on the other hand flows slightly better on the exhaust side. In the past, performance junkies would always prefer the 062 to the 906 because of the perceived better exhaust flow characteristics, but more recent dyno tests have proven that the performance difference between the two is negligible.

    I dont regret my choice at all, the engine has been great for the past 7 years. I have about 80000km(50000miles) on it. I have pulled travel trailers and car haulers, which really put the engine to work. By today's standards its not the most powerful engine, but I am in no race, and it has enough grunt to move anything I want it too.
     
  8. PlayingWithTBI

    PlayingWithTBI Desert Old Guy

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    I learned a long time ago in business and personal life, by the best you can afford at the time and you'll never regret it.
     
  9. 89GMCJOHN

    89GMCJOHN I'm Awesome

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    4 bolt.
     
  10. 94burbk1500

    94burbk1500 I'm Awesome

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    is this a real question? 4 bolt
     
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