Noise from out drive when giving it throttle

[cosmiccharlie1976]

I have a 88 sea sprite with a 3.4l and mercruiser alpha 1 gen 1 outdrive.
I have replaced the engine block and reinstalled the motor. I used the alignment tool to install the lower unit. The motor idles great and sounds great but when I give it throttle wether in gear or nuetral it makes a loud vibration sound.
it did not make this sound until I installed the lower unit.
Thanks, I appreciate any thoughts on what to do.

 

[alldodge]

It's a 4.3L according to your other post

Sounds like fan blades hitting something, like maybe the alternator

 

[dave8311]

Tilt that drive down before revving it like that.

Is that your u-joints being destroyed?

 

[Scott06]

Check what the drive lube looks like. Would also try moving drive down to see if it goes away or changes, but if so pull drive inspect ujoints and gimbal bearing

if its u joints a moog 315G will fit