On my 355 rebuild, the guys at the machine shop are balancing the front balancer/pulley neutral (since the front of the motor is balanced internally). They are also using the flywheel, PP, and clutch to balance with the rear of the motor since it's externally balanced. First of all, is this correct? Secondly, what do I do when I need to change my clutch, PP and/or flywheel? Can I go to an aftermarket flywheel if I'm using stock now?

I'm asking this because I don't know how they're going to match the new stuff to the old stuff since they are wear items and won't weigh the same with more use.

Parts: stock crank, eagle H-beams and Mahle pistons, stock flywheel, spec clutch and PP.

Thanks.

 

the front balancer and pulley are neutrally balanced at zero. i gave my machine shop both those parts and he just gave them back to me after spinning them, because they were at zero. the flywheel and the PP should be zero balanced as well. however, you can make a crankshaft internally or externally balanced. in your case it sounds like they are going to spin your crank with the flywheel and make it externally balanced on the rear through the flywheel. just use the stock flywheel and get it resurfaced. your machine shop should answer all of your questions but you should be good to go.

 

They said there is no way to make it internally balanced at the rear with the stock LT1 crank. I thought I'd read that here, too. You can't buy a new stock flywheel anywhere, so that's why I'm asking about an aftermarket piece.

 

Centerforce CTF-700177
Flywheel, Steel, 153-Tooth, 29 lb., External Engine Balance, Chevy, Small Block
Engine Balance: External, 23.4 in./oz. imbalance

Perhaps the shop can spin your stock one and give you a spec card with location and weight to use on an aftermarket zero balance flywheel.

 

I'm not sure about the stock crank not being able to be internally balanced, but it'd be best to get the rotating assy. internally balanced. If you ever need a new flywheel for any reason and it's externally balanced you will more than likely have to take the entire rotating assy. out of the block to rebalance it again.

 

i would have them internally balance the front and back, and then zero balance your flywheel.

 

all it takes to zero balance a LT1 crank is some heavy metal(mallory metal)

 

you can internal balance a stock crank with heavy metal but I have to ask why? You would need a more than normal amount and its not cheap... by the time your done you probably could have bought a new crank. Its easier to just external balance the stock crank and put it together. Doesnt sound like you doing a big HP build... more like a mild overhaul and you will be fine with external. Either way they will need your flywheel to go with it. Many will also want the balancer just to check it for neutral... its not common to need to re-balance an aftermarket balancer that is already a zero balance piece. Stock... get it checked.

 

usually, they will balance the crank to work with a stock balance flywheel, so it's not like you are going to have a custom balance flywheel

 

If I had a stick - that's what I would do.
I only found that one Centerforce flywheel and it's $485
And this: RAM for $379
Billet Aluminum Flywheel
1993-97 LT1 F-Body
Balance: External
Ring Gear: 153
Approx. Weight: 18lbs
Bolt Circle: Factory 10mm Pattern

I did not find an LT1 flywheel at GMPP

Even neutral balance aftermarket flywheels are the same price ranges - check it out at Summit/Jegs

If he leaves it balanced in the rear by the flywheel, you are limited and at the mercy of the manufacturer of the next flywheel that the weight is located and weighs the same.

If he knocks the weight off your stock flywheel and test's it to zero, then balance's the rotating assembly to zero - you can use any flywheel down the road, and balance it to zero before installing...

 

Like I said, chief, there are no more stock Flywheels, just billet.

Using heavy metal isn't an option due to cost. The 383 crank isn't the same as the stock crank.

 

Sure looks that way

I guess if you leave the internal balance as factory - you at least have a shot at finding useable stock flywheels. Or if you zero balance your stock one now - with the assembly - you'll have to buy zero or machine to zero any flyheels in the future.

I don't know what type of driving or miles you will see after you rebild - but I would think one quality new flywhel should last a very long time.
If you build a 383 later - whatever choice you make now will still apply - regarding aftermarket flywheels.