ok i have a 350 1 peice rear main seal block. I want to make it a 383 and it goin to get balanced. Some people r saying the fly wheel and balancer off the 305 will be fine to use to balance it with others they say i cant use them im confused. If the 305 parts r fine i still want to get a new balancer what 1 do i need ????? internal or external balanced so confused.

 

A heavy metal (I forget what it's called off the top of my head) can be used to balance a 383 crank so it is internally balanced and "normal" damper & flexplate can be used. It's typically a bit expensive to have this done, but could be considered worth it in light of being able to use more normal parts.

 

A 383 can also be internally balanced without the use of Mallory metal, if a non-stock crank is used along with 5.7" or longer rods.

In short, the only way to know what balancer to use, is to know exactly how your particular 383 is built. There's no one-size-fits-all answer.

 

i also want to use a after market balancer what is a good 1 to use

 

What brand of crank are you going to use?

 

i dunno the machine shop guy is ordering it he told me to buy a 400 ex balanced balancer and my fly wheel will be fine so thats what im gonna do i guess. The problem is finding a 3rd gen 1 peice rear main seal fly wheel for a 5 speed so i dont have to rip my car apart alrdy

 

Ahhh, a manual! Ya you will need an 8 inch exteranal balance dampner most likely. You will have to hand off the flywheel to the shop as they cant balnce the assembley without it.

 

i just bought a 400 external balancer from summit 6.6" o.d. its sfi approved. Why 8"

 

You should be set with what you bought. Stock 400 exteranl balance used an 8 inch dampner, stock type replacements are 8 inch. Some of the more expensive aftermarket stuff that is for 400 external balance comes in diameters other than 8 inch.

 

kewl thanx i cant wait to get this thing done i been lookin at some vortec heads now

 

Your flywheel will not be fine! You need an externally-balanced flywheel (more than just the one-piece rear main seal type of external balancing).

 

yes it is going to be

 

Most of the one piece 383 cranks come close to being ballanced using the regular flywheel used on the 1 piece seal. Considering its impossible to get a flywheel from a 400 to fit a 1 piece crank.

 

exactly they didnt make a 400 1 peice

 

I know "they" didn't make a one-piece rear main seal 400. That doesn't prove your point.

Better research this carefully before bolting it together. You're in for a good shakin' if I'm right and you don't have the right parts in it.

 

five7kid, the crank manufactures have the fact in mind that there are not that many options for the one piece rear seal flywheels, they make the last counterweight a little heavier just for that reason. The setup does still need to be balanced, but you can balance it using the flywheel from a stock one peice rear.

I have done these before.

 

I'm willing to learn. Funny I've never heard any of that before, and after about 30 minutes of searching, this is still the only place on line I've seen that said.

 

in your 30 minutes of research did you find anybody doing it different than what I have said...I too am willing to learn, and if there is another way Id like to use it, but like I said I have done a couple of these 383's with one piece rear seals for people and on every one of them I have done it with there original flywheel/flexplate on the crank.

 

thanx for the info aron and yes the place that is goin to balance it told me that also so im sure they know what they r doin.Does ne1 know how many teeth my fly wheel on my 90 camaro would have its a 5 speed 305.I want to find another 1 so i dont have to take my car apart yet. Any measurement i could take to know it the right 1 thanx. The junk yard said they had 1 but i never trust them

 

153 teeth on the stock T-5 Flywheels!

 

awsome thanx man neway to know if its for a 1peice crank

 

Most of the aftermarket "383" cranks, especially the ones for 1-piece blocks, are set up for long rods, which leaves enough room under the piston at BDC for enough counterweight to internaly balance.

The reason the 400 is externally balanced is because of the short rod. When the piston is at BDC, the counterweight is at TDC so to speak; and with the short rod, the piston is so close to the crank centerline, that they had to shave the center portion of the counterweight off to allow it to pass under the piston without hitting; and that lightens the counterweight so much that even with drilling the rod journals, balance weight somewhere else is still required. With longer rods, there's enough room for the counterweight. Longer rods however require pistons with the wrist pin bore moved up toward the top of the piston, and even with 5.7" rods, this puts them up into the oil ring. The factory saw the external balance as the lesser evil to that ring issue, that's why they did what they did.

Again, I can't say it strongly enough, make sure of what parts you've got. There is no universal right answer to this question when you get into the aftermarket parts. What five7 is saying is true for stock parts, but doesn't necessarily apply to others. Be certain of exactly what you have before you make a mistake.

 

If the question was anyway to know if its for a 1 piece crank,
The answer is yes, by looking for the counter balance on the side that faces the engine.
Another thing kind of related to what RB was saying about making sure about the parts you have, one thing to consider is this, any flywheel you are going to find in a boneyard, the chances are it has been turned once, twice or who knows how many times, when I was building a 383 a couple years ago, I was also going through the Flywheel and machine shop balance dilema, I opted to just buy a new flywheel to bring to the machine shop instead as I didnt want to find out down the line after a clutch change or two, that the one that they balanced with my assy, was not worthy of being turned any furter because it was getting to thin.
Just my advice!

 

i mean is there a way to know it the fly is for a 1 peice by lookin at it i know the block is. Like some measurements between the bolt or somethin. And yes ive asked alot of people about this question finially i got the engine builder to call the place he uses to balance and they told me to buy a 400 style balancer and use my flywheel.

 

I don't know the numbers offhand, like bolt circle or pilot diameter measurements; but the 1-piece has a much smaller bolt pattern than the 2-piece.

What you're saying he told you doesn't make any sense. Ordinarily you'd see either a 400 balancer and 400-balanced flywheel, or a 305/350 balancer and a neutral-balanced (or the very slight unbalance for 1-piece crank) flywheel. I wouldn't expect to see a mixture of the 2.

Make sure that if there's a problem, he's ready to stand behind it and take care of it.

 

i beileve he will we know him well hell give me good deal i mean i got the 4 bolt main roller block for 125 dollars. ALso look what aron said thats a good point also he said he has balanced them b4

 

I think there is a slight misunderstanding, you can identify like I mentioned above a 1 Pc Flywheel by a counter weight on it facing the engine. On 1 Pcs there is always a counterweight. If it is a 2 Pc. Flywheel there is no need for a counter weight at all unless it was on a 400 or a stroker motor. (unlikely at a junkyard) and the 400 ones are typically the big 168 tooth design. If this doesnt clear it up, I will get a pic for you of the flywheel you are looking for when I get home from work.

 

thanx that cleared it up i guess im on my way to go get in now tho. Ill look for the 153 tooth and the counter weight on the inside

 

well hmm lol maybe not i justed called advance and for a brand new fly wheel they want 85 dollars and the junk yard wanted 65 for a used 1 lol that guy over prices everything.

 

I would definitely go with a new one then!

 

Every 383 one-piece seal crank I found was called "external balance". No other details were given. Summit, Jegs, Eagle, Powerhouse are what I recall looking at.

If it is true that all you need are external balance damper with "normal" one-piece flywheel/flexplate, I call that very good news.

 

omg im getting soooooooooo pissed at part stores and junk yard there all retards. I have been all over the place this week cause of ignorant people. First i called a junk yard the other day said they had 1 went over there dont have 1. Called advance said they can order 1 went over dont carry such a thing. What the hell!!!!!!! Now i have to drive over to this other junk yard for them to prob tell me they dont have it now also.Im tellin these people i have a 5 speed

 

hey if i stick with a 350 since they r internally balanced cant i switch to a 6 speed flywheel later on and not worry about throwin off the balance

 

The last 383 I was part of we used a cola lightweight crank, eagle h-beam rods, SRP pistons and the stock 350s (was a 90 truck block) flexplate and dampener, he balnced the whole assembly together and only had to add less than 4 ounces of mallory metal to the crank , a whopping 160 $ for the balnce job. Since the dampener was untouchrd in the process we moved up to an 8 inch neutral fluidampener it works great. Of course the price of the crank new was 900$ , but you get what you pay for.

 

I just had my 383's rotating assembly internally balanced. I am using an Eagle 4340 3.75" crank (2 piece), Eagle 6' SIR Rods, and SRP blower Pistons (9.5:1 w/ 72CC AFR 195).

I will be using a fluidamper for a 350, and a neutral balance SFI flexplate from TCI....