I bought a 1st gen GM crate 350 and all I need is the vibration dampener for it and I can swap it in.

I have a 89 pontiac 305 parts engine. Can I use its Vib. Damp. or will I run into problems?

Thanks guys!

Yea, i'm pretty sure they're both considered "internal balance". Just make sure you use the pre'87 flywheel on it, you can't use a post 1987 flywheel. It's... not the right balance.

The 305 would have a 6 3/4" balancer though, usually 350's spec an 8" balancer. What I mean is if your timing cover and timing pointer are meant for an 8", you'll get wacky numbers using your 305 one. If you want you can turn the engine over to TDC#1 (use a piston stop), then calibrate the balancer to 0.
Or just buy summit's basic one for $62. It's got timing marks from 10 ATDC->60BTDC.

So I need a flywheel for the 350 too? I cant use the 305 flywheel?

SOB.

That's correct. The 305 flywheel should have the "batwing" weight on it. It's a post '87 weighted flywheel.
You'll need a pre-87 internal balance flywheel. You'll want a 153 tooth one though, and use your 305's starter.

Thanks for your help Sonix.

Ill take some pics of what I have. Im guessing the brand new clutch I also have for my 305 won't work either huh?

Yep, that should work fine. You get lucky with that one.

You're using the same tranny? same splines on the input shaft so same clutch. You're going to be using the same size flywheel (10 3/8" = 153 tooth) so that's all fine, only you need a flywheel that doesn't have the batweight of the '89 style.

A flywheel for '83-85 3rd gen 5-speed will fit the engine and work with the tranny & starter.

There has been all sorts of back & forth on the topic of using a 305 damper on a 350. The issue isn't whether or not it will fit, but rather whether it's a wise thing to do.

There is one "fit" issue - where's the timing tab on the respective engines? I believe the crate engine will have the tab at about 2 o'clock, vs. 12 o'clock on a lot of 3rd gens. If they're both the same, then you have to ask yourself other questions.

Both 305's and 350's have used the smaller 6" and large 8" dampers. So, that's not really the issue, either. But, some argue that 305 and 350 dampers are "tuned" differently - and to that, I have no direct answer. It could very well be the case.

Regardless, you can get a good 350, 2 o'clock damper for $50-$75. When you're spending over a grand for the engine, an additional $75 is cheap insurance.

^Ok so I need to check my timing tabs but I think Ill still call up summit or someone and verify differnt part numbers.

Ill load pics tonight of the flywheel to see if it has this bat weight.

Thanks alot guys. Its been a huge help!

If it's from a 1989 small block chevy it has it.

Make sure the timing tab on your new motor is in the same place at the motor you are taking the balancer off of or it won't show corret timing when you shoot it with your timing light. GM used 2 main locations for the timing tab- at the 12:00 position stright up behind the water pump and at 1:30 sticking out near the driver's side leg of the water pump.