olds to chevy conversion question?
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olds to chevy conversion question?

  1. #1
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    Default olds to chevy conversion question?

    anyone now what angle motor needs to be. Im puttin in a chevy where a olds was. was able to use same holes in back as Olds but need new holes up front. I think the angle was up in front by 3 degrees. I just want to confirm with someone that has done this before.

    level boat on trailer by puttin level on top of stringers?
    then get a angle finder and put where on motor to check the proper angle for motor?

    i dont have intake on.

    can i lay flat piece of steel across block front to back where intake would be and put angle finder on that?

    or could i use measurements from original olds front holes measure how high those holes are from bottom of bildge and drill the new ones at same height?

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    Senior Member slotracer's Avatar
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    you will get all sorts of answers on this one. i like to leave the front down 1 or 2 degrees when i do a install with the thinking of the carb will be level when you are on the gas. but thats my way. are you using a digital level? do you have a manifold to set on the engine to use? do not know if using a flat peice of steel would work being that some manifolds have a angle built into them and i like to run the carb as flat as possible. just reread your post if you are using the back holes already thats going to dictate where your front goes unless the holes are oblonged out.
    Last edited by slotracer; 06-28-2008 at 10:21 PM.
    slot
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    jetboataholic HawaiianJet's Avatar
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    Quote Originally Posted by slotracer View Post
    you will get all sorts of answers on this one. i like to leave the front down 1 or 2 degrees when i do a install with the thinking of the carb will be level when you are on the gas. but thats my way. are you using a digital level? do you have a manifold to set on the engine to use? do not know if using a flat peice of steel would work being that some manifolds have a angle built into them and i like to run the carb as flat as possible. just reread your post if you are using the back holes already thats going to dictate where your front goes unless the holes are oblonged out.
    Very good point there!!!!!!!!!!!!!!!
    HJ

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    Driveline angle should be 3 or 4 degree's.
    If you swap a Olds for a Chevy and if both engines use the same style 4 point mount you can keep all the feet attached to the stringers in the Olds mounting locations. The Olds is exactly 1/2" longer when measured where the front and rear mounts mount at. I made a pair of 1/2" thick spacers for the front mount of the Chevy and it bolted in with no further modifications. In the picture you can see the spacers between the engine mount and the engine.

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    Sit N' Spin Jetaholic's Avatar
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    In regards to driveline angle I think a lot of people confuse "angle" with "offset".

    "Offset" would be when the crankshaft centerline is slightly higher than the pump shaft centerline or vice versa. Dual acting u-joints (i.e. 1310 or 1350) are designed to be able to take a certain amount of offset. You actually want some offset in the joint to keep the needle bearings moving.

    "Angle" would be the angle of the crankshaft as compared to the angle of the pumpshaft. The crankshaft angle can be no more than 3 degrees relative to the angle of the pump shaft.

    You also want an equal distance between the transom and the rear of the engine on each side to eliminate any sideways offset in the joint.
    Last edited by Jetaholic; 06-29-2008 at 12:35 AM.

  8. #6
    Senior Member slotracer's Avatar
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    Quote Originally Posted by Jetaholic View Post
    In regards to driveline angle I think a lot of people confuse "angle" with "offset".

    "Offset" would be when the crankshaft centerline is slightly higher than the pump shaft centerline or vice versa. Dual acting u-joints (i.e. 1310 or 1350) are designed to be able to take a certain amount of offset. You actually want some offset in the joint to keep the needle bearings moving.

    "Angle" would be the angle of the crankshaft as compared to the angle of the pumpshaft. The crankshaft angle can be no more than 3 degrees relative to the angle of the pump shaft.

    You also want an equal distance between the transom and the rear of the engine on each side to eliminate any sideways offset in the joint.
    hey jet you better read it again. he is asking about ANGLE not offset.
    slot
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  9. #7
    Senior Member slotracer's Avatar
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    Quote Originally Posted by hotrod56cars View Post
    Driveline angle should be 3 or 4 degree's.
    If you swap a Olds for a Chevy and if both engines use the same style 4 point mount you can keep all the feet attached to the stringers in the Olds mounting locations. The Olds is exactly 1/2" longer when measured where the front and rear mounts mount at. I made a pair of 1/2" thick spacers for the front mount of the Chevy and it bolted in with no further modifications. In the picture you can see the spacers between the engine mount and the engine.


    lesson for the day/ olds is 1/2" longer than chevy. never knew this. instead of drilling new holes make spacers
    slot
    87 eliminator
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    new owner of the redneck yacht club
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    Quote Originally Posted by slotracer View Post
    lesson for the day/ olds is 1/2" longer than chevy. never knew this. instead of drilling new holes make spacers

    tHANKS hOTROD.. I had Hardin olds plates and have Hardin chevy plates now... so im gonna do like u said & I will be makin spacer's 1/2 thick then.
    thats easy enough!


    Casey

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    When I made the spacers I decided I'd rather run a pair of spacers than drill new/more holes in the stringers. Piece of cake!

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    Hey Tom ...you out there?
    ok Update..Made the 1/2 spacers for front of block just as suggested by the boards and had to shim motor from left to right by 1/4 by makin side spacers so I could center driveshaft to motor(new chevy motor plates had holes drilled like 1/4 off from Olds plates).
    k thats done.and that centered motor to pump.

    Then I got it all mounted in and bolted driveshaft to PTO which looks centred but has a negative angle to bolting to motor from pump. I guess thats ok as long as its not level which could wipe out the unjoints.?. Must have been that way with Olds and never noticed it?reason it must be same as olds is that I used the same feet, same brand Hardin motor plates,same holes in stringers,same driveshaft and both Olds and Chevy take same bolt pattern on bellhousing except top 2 bolts.
    Im attachin these pics as Im not sure angle of driveshaft from pump to motor is not to drastic. I did spin it over by hand it doesnt touch anywhere and turns freely.Just want to make sure before i proceed any further.















    Tom what ya think...


    Casey

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    Lesson for the day, there not all the same! Damn, the driveline angle on mine didn't turn out anything like that. On mine, the driveline angle wasn't changed, I didn't have to re-center anything...

  14. #12
    Senior Member slotracer's Avatar
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    looks like the back plate was drilled different on the chevy then the olds. raise the back up some and redrill the holes on the rear mounts. you could either do that or find some mounts the have not been drilled yet. no biggy either way not going to have to raise it that much to fix the angle
    Last edited by slotracer; 07-12-2008 at 03:05 PM.
    slot
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    Senior Member jetboatperformance's Avatar
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    Yikes Casey !! call me Tom (up in the back more to begin)

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    ok thanks guys. redrilled!!!

    I can see slight angle upward ever so slightly and used level def not level.How about now.





    Casey

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