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Gearing and towing with a 383 stroker question.

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by shum1, Jan 18, 2001.

  1. shum1

    shum1 1/2 ton status

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    Here is the deal: Im looking at a new engine. I now have 3.73 gears and a new700r tranny. I have 33" tires in my basement waiting for my lift. I tow a boat every year on the highway to cabo san lucas mexico at 70mph. In third gear with 31" tires, the engine is quite busy at this speed and I'm reluctant to go lower in gearing. After I mount the 33's I can either spend the $1000 for 4.11's plus $2000 for a replacement 350 with a rv cam or I'm thinking I could get the 383HT when it finally come in for $3000 and stay with the 3.73's allowing me to run lower rpms for long distance. Any thoughts or guidence would be great. Thanks.
     
  2. Burt4x4

    Burt4x4 3/4 ton status

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    Well my first thought is that you will be waiting a long time for theat crate HT383, GM had some staff changes and that product got canceled before it even made it to the parts house. Thats what Pace Parts said anyway!
    I would say if your K5 is not for trail crawlin or granny gear useage then stick with your 3.73s and have a well built 350 or stroker for the continueous duty type of build. It would really suck to have a fancy HP motor die on you in Mexico!! So I would keep the build to a real world or ground level type of build hey mabie even the $1500 crate 350 would be your best bet for thoes long hours of haulin, just have them build it for towing!!???
    Good Luck

    72K5[​IMG]Led Zeppelin[​IMG]Rock ON![​IMG]
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  3. Blue85

    Blue85 Troll Premium Member

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    Remember that as soon as you slap on those 33's, your engine rpm's will drop quite a bit, about the same as if you dropped back to a 3.43 gear with your 31's. 4.11's with 33's will give you a higher rpm than 3.73's with 31's.

    If it were me, I would definately stick with the 3.73 gears and save the money for something else. It sounds like you wouldn't want to change the gears by more than 1 step anyway and that probably wouldn't make enough difference to justify the cost or work.

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  4. JimmyDie6.2

    JimmyDie6.2 1/2 ton status

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    I have 3.42s in my rig with 33s and a 350 now. I have no idea how much boats weigh, even if I knew its length. Just as a comparison though, I tow a full bodied GTO to the track at least 6 times a summer. with tools galore and sometimes 3 friends. I would say about 5500 pounds total in and behind the truck. I use drive only and cruise between 65 and 70 the whole way, I tach at about 2100. I have no problems towing, the only time I could use more power is going up the verrazzano bridge on those englishtown excursions. But, one could say, we can all use more power going up a bridge. I think you will be fine towing with 3.73s. I had 3:73s in an old burb I had, on occasion I would drive all the way to buffalo towing a car with a 400 trans at 70MPH at least, with 31s. you should be fine. By the way spending a thousand bucks to go up one gear set is a little assinine to me. Consider 4.56s if you go for the swap. you posted that you were going to add a lift to the truck. with 4.56s you would be cozy with 35s even................js
     
  5. ftn96

    ftn96 1/2 ton status

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    Shum1, by saying quite busy, Im assuming that you are talking about the rpm's being a little high. If this is the case, I'd leave everything the way you have it and put the 33's on when you get the lift. This will bring your r's down to where they should be. But for towing, I would not be using the overdrive. YOu may or may not have know this, but just letting you know. With a 1:1 ratio 3.73's and 33's, In my honest opinion, is the ideal setup for the daily driver/part time wheeler. But your out there in the mountains, so you may want to consider just adding that RV cam to your current motor ot give that little extra power your looking for while towing. Just my pennies, dont spend them all in one place.
    Your in the mountains and Im not, so I cant really rationalize with you correctly.

    Will work for parts, beer and sex.
    90 Jimi,350/700R4/241/10bolts/3.73's/33's/4"
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