I have just finished my 96-M6- 383-LT1 with basic votech kit 6-8 lbs.I have the Loyed Elliot stage 2 head/intake port to match 52mill throttlebody,and eagle 3.75 /5.7 rods.Pcmforless mail order tune,LT4 knock md,msd 10 mill wires,tr6 plugs,cloyes double roller timming chain,1.6 rr all the goodies.The eagle stroker kit that I bought I paid extra $$ for internally balanced.Srp dished pishtons too.Passesetter long tubes/with exhaust no catsI have stock balancer,and stock flywheel on this.I have to get my cam card for the specs but I know it is a comp cam with a 576/lift.

It started right up and sounds badass.When I started driving this there is a vibration in this that kind of scares me and some other people.I have put 45 miles on this,and it runs really sloppy/bad/not smooth/up and down with speed.

Does anyone with a 383 supercharger have an aftermarket balancer that works with the pulley from vortech?Does anybody also know if I should get that flywheel neturally balanced/b/c this may becausing the vibration?I need some help car has been sitting since first notice of the vibration.

 

may want to check the tune, it may be off if its running sloppy

 

is it your stock flywheel, did they balance flywheel w/motor

 

You need a nuetral balanced flywheel if they internally balanced the rotating assy. If they balanced the rotating assy without the stock flywhel and damper, then you must have a zero balanced flywheel... the stock flywheel IS balanced (weighted) and isnt the right one to use.

 

Is the stock balancer ok to use?

 

The '86 to '97 "internally balanced" chevy v-8's weren't truly internally balanced. They were internally balanced in the front (unlike a 400 SBC) but not in the rear. Alot of people are confused by this. I bought an Eagle 3.75" crank that was internally balanced. I fully expected to use the stock 1-pc rear seal flexplate because it's for an internally balanced chevy, though it has a counterbalance weight. When balancing, we found that simply removing this weight balanced it perfectly. Now, it is a TRUE internal balance, as in, both the flex plate and balancer are neutral.

Mike

 

yes

 

Not with the Vortech pulley. It won't mate up right.

 

I thought the vortech pulley bolts to the stock crank pulley (thats what it said with the S tirm kit I had)?

 

The front surface on the stock pulley is cast and not very uniform. Not sure when, but Vortech started supplying balancers with their kits with the front machined into a smooth, true surface.

 

im glad u brought this up, i was wondering about this the other day. so all i have to do is take off the weight right?

 

That 383 supercharged LT1.How much should it make with a good dyno?

 

I got lucky. The piston weight can throw things off quite a bit. Pistons can be anywhere from 350 to 700 grams, so I wouldn't do anything without spinning it up on a balance machine.

Mike

 

I had the same pfoblem with my new engine. I had the weights removed from my flywheel and then balanced to zero and that fixed the vibration.