[tomlll]

Hey Guys,
Need some help. I have a 66 coupe and I yanked the 289 and replaced it with a crate motor from a place called the engine factory. I do not know year of the 302 block(not sure how to tell either). They provided the flex plate, balancer etc. I am not sure if it is a 50oz flex plate or a 28 oz.

Bottom line is the motor runs great, but I have a lot of vibration. Got any ideas?

[EagleAutosports]

Hiya, I see this is your first post, welcome to the site.
I'll move this to the Mustang Tech area so it can get the best exposure for your problem.
My question would be does it vibrate when the car's in motion? When you rev it? Does it make noise when it vibrates? Does it loose power when it vibrates?

[tomlll]

Thans for the help, just getting to understand the site.

At idle things are pretty smooth. Around 2-3K rpms it really starts to vibrate. You do not have to be moving so I believe it is associated with the engine.

[Tominator]

It very well could be a mismatch in flex plate or balancer.

First, DO NOT drive the car until you determine the problem. I really doubt any warranty will cover an engine failure caused by the above even if they provided same.

Call the folks that built it and describe the problem.

A mis-match, as described, is just about the worst thing you can do with very few exceptions.

If you do not know, pull the motor and examine the crankshaft to determine the balance.

Flex plates are cheap!