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  1. #1
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    Post TRS MERC

    I have a 1976 18 classic with a TRS. please give me info. on this drive.

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    Thumbs up

    It's big and heavy and tough as nails. If you ever need to remove it, don't try to lift it by yourself - get a helper! Most likely you have the MercTrans rather than a Borg-Warner transmission between the engine and the drive. This is a great transmission as Big Grizzly has proven by pushing nearly 750 HP (or more) through his MercTrans to take the high honors at the recent Eufaula IV Donzi event with a top speed of 89 MPH in his 22' Donzi Criterian with no more than a stock TRS drive and his favorite propeller.

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    Most likely you have the 330 TRS. If you do, then you have the Merc Trans. I also have that unit on my 1978 F22. I'm running similar power and speeds as Big Grizzly and it's holding up pretty well. I did have to replace the clutches with some H.D. ones but with the 330 you may never have to worry about that.
    "1978" F-22; Turbo'd & Intercooled.

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    There's TRs and there are TRSs - have no idea of the differences. The real designations are the II-TR and the II-TRS. Introduced in 1970 and ran up to 1987. There is also something called a 215E and 215H (1970-1973) that had external transmissions and as with the TR/S can be set up right hand or left hand. The 330 tr and trs didn't start till 1977 model year. In '76 ya had the 255, 270,280 and the 370. I believe Randy put a wing of his own design on the skeg of his TRS.

  5. #5
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    Had a TRS on my cigarette with a Borg-Warner Transmission. Never had a problem.

    Bullet Proof combo.
    "Support our Troops"

    Dave
    Always a Gearhead

  6. #6
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    The TR's have bigger lower gear cases and use elephant ear props. Used often on house boats and other low speed slugs.
    "1978" F-22; Turbo'd & Intercooled.

  7. #7
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    Cool

    Hey Rodger,
    Don't be calling Randy's 22 a slow speed slug!!! That boat really moves with a TRS!
    Bill

    Bad Puddy-Tat
    96 Blackhawk
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    Wait, Thanks for the build up, but lets get this right. I don't have over 700 HP and that boat goes on its best day high 86 mph. But I do agree the trans is tough and it is really smothe when put into gear. There has been a discussion about the power robbing trans, this is bull. Yes the TRS and Merc trans does use more hp than a bravo I by about 7->14 HP. I heard stories ot 20 to 40 Hp so I asked Tom Huber of Huber marine who is an expert and modifies the Borg trans forand he gabe me the numbers. This is the guy that the other guys copy
    Randy owner of Donzis since 1966
    High Performance props 3, 4, and 5 blade. Turbo and Stainless Steel props. Props for old Volvo drives.
    The reason congressmen try so hard to get re-elected is that they would hate to have to make a living under the laws they've passed.

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    Hey Bill. I assume your teasing me. If your not though; what I am talking about is the TR unit being for low speed slugs, not the TRS. I have a TRS on my 22. Under the water, they are more hydrodynamic than the Alphas or Bravos because of the longer gear case. The diameter of the gear case is about the same.
    "1978" F-22; Turbo'd & Intercooled.

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    Actually, if it's a small-block TRS setup in that '76 18 Donzi, it's most likely a 255hp or 280hp TRS. The Merc TR (not TRS) swings a 20" diameter prop and is designed for moving heavy loads.

    OK Grizz, if figured the BG shirt was worth at least 50 more hp and 3 mph!

  11. #11
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    Allan,

    -----TRS drives with small blocks went on a number of 18s.How many I dont know,but not a particularly large number.John Chisholm told me back in 79 when I bought an X-18 with TRS and big block(new left-over)that there were only 6 of those built.The factory was concerned about liability issues.And I can add that the boat was a handful.There may have been a few small-block/TRS combos converted to big-block as well.Although heavy,the packages were(as stated above)very hearty,shifted nicely,and as a bonus looked bitchin!Carburetor clearance was always an issue though.......just......ol red!......Bill S

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    I personally know of 3 people who bought original Big Block TRS 18's. As I remember they had to put bumps in the engine cover for the flame arrestor and both exhaust risers.
    "1978" F-22; Turbo'd & Intercooled.

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    Thanks for the info! My 18 is a 350 chevy TRS and hatch cover does have the bumps for the risers and a scoop for the flame arrester. Does any one know the gear ratio,or how I could figure it out? The owners manual that came with the boat gives two options;2:1 model 255-TR, or 1.5:1 model 280-TRS.

  14. #14
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    You most likely have the 280TRS package. The TR drive was for heavy work /house/cruiser boats.

    The TR drive lower was deeper and would accept a 20" dia prop

  15. #15
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    I also own a 1976 18' 280-TRS. The 280 was a 1.5 to 1 ratio where as the 255 TRS was a 1.33 to 1. I have the two scoops for the risers on the hatch but none for the flame arrestor although it was pretty much scraping the hatch cover. The 350 is no more, a 383 is on the way but for reference, the 280 TRS was basically an L-82. The heads were nothing special, 1.94/1.5 with the cast iron quadrajet intake and carb. The bottom end of the engine was pretty decent - four bolt block with nodular iron caps, 6-quart baffled oil pan and windage tray, forged crank, forged aluminum pistons and "pink" rods. The best performance I could get was 62mph at about 5000 RPM. This was on a pitot tube stock Teleflex speedo not GPS - hard to say what the real speed was. I was using a 14 3/4 " X 21 pitch cleaver prop. It may have done a little better if I had a better ignition - stock single point Prestolite distributor. The cam that came out of the engine was an L-82 cam. Hydraulic lifters, 222 @.050 on both intake and exhaust, .450/.460 lift in/ex on a 114 degree centerline - GM p/n 3896962. I matched up the casting # off the cam to the Chevy parts book to derive these numbers.

    The boat shifted great although I did burn up 1 shift motor which wasn't cheap then and isn't cheap now. I spoke with BAM marine recently and they told me that with two comparable boats, one with a TRS and one with a Bravo, The Bravo is about 2-3 mph faster. I considered switching to the Bravo but have decided to keep the TRS for now.

    The 383 I'm putting together(due 2008), according to the desk-top dyno, will make 430HP. I will never blow the TRS with that.

    Question - I'd like to have the bellhousing separated so I can prime and paint it properly with awl-grip and then have it re-assembled. It's hard to tell if the bushings/bearings actually need to be replaced but since the boat is totally disassembled and it's a quarter century old, I can't see putting it back together without going through it first. It has about 420 hours on it. The question - is it really worth it or am I just inviting problems with parts being frozen, then cracking and then not being able to get replacement parts.

    Also, if I go this route, I need a recomendation of some one who can do it. Any/all suggestions will be appreciated.

    Thanks,

    Dave

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