my75baby

Is there any way to tell the size of the flywheel I have now? the part number is 50-6054, which is the 350 flywheel, does anyone know if this is a 168 tooth flywheel? and what the diameter is? I ask this so I can order the 400 flywheel, I know some vets had a 153 tooth flywheel.. can someone tell me by the above part #.

Additionally, I have to look for the part # on the tranny, I believe it to be a muncie, I want to order a new clutch as well, I want to buy one with the right splines so I can have all the parts ready. Anyone with ideas??

PuddleJumper

i have an parts exchange book i will have a look here and see what it tells me ok

Ryan

my75baby

Thanks...

wfo76

Not a GM part number.

Check your bellhousing number (cast on side)

3899621 ... 14 inch, 168 tooth, 11 inch clutch

3858403 ... 12.75 inch, 153 tooth, 10.4 inch clutch

I'm betting you have the 621.



Your 75 should have a Borg Warner Super T-10 and it needs

a 26 spline clutch. Look for a main case number like 1304-065-903

to positively ID.

PuddleJumper

well i told an few things

1 is the 12 1/2 in is an 153 tooth and the 14 in is the 163 tooth

as for what the 50-6054 i cant find anything to tell me what the No. of teath it has

PuddleJumper

my75baby

Thanks again, yes i was able to look up the flywheel part number on the net, it is for a 350, which side of the bell housing has the casting number on it? many thanks...

wfo76

passenger side

my75baby

Thanks, I will look later in the week..

jackson

When you 1'st wrote that part number several posts back ... I thought the format looked familiar ... like a Perfection / Zoom #. I looked it up. Close but No. But ...

Is it possible you might've transposed 2 characters? Please verify. Why?

Because 50-6504 is a good perfection # ... it's a std weight 168T for a 2pc rms 350sbc (not for 400!).

The correct FW for 400sbc is 50-6567, also std weight 168T. YOU should verify this.

Go to www.perfectionclutch.com for more info ... fyi, they're in my neck of the woods & they were primary sponsor on a purple late model circle track car I co-owned a few years back.

Me thinks you should put YOUR eyes on YOUR trans splines before you order. Perfection & Zoom sold at Advance AP, NAPA etc.

dstaley

If you are going to inspect your bottom end:

Before you run out and buy a flywheel, confirm that you will not be replacing your crankshaft.

If you end up rebuilding this engine, you might end up with an aftermarket crankshaft, new rods, and new pistons. If you do this, you will find that it's not very hard to internally balance a 400 assuming you use modern parts. I did it, and I'm now using a neutral balanced flexplate. You will be able to use a neutral balanced flywheel (the one you already have) if you take this path.

However, in this case you will need a new (neutral balanced) harmonic damper. A new damper is a better compromise, IMHO, than re-using a 30+ year old one anyway.

BLOCKMAN

They actuaaly make a weight that goes between the flywheel and the crank just for this application as we just sold one o a guy last week that wanted to use a 350 flywheel on a 400.

Goodson sells them

MotorHead

I would also make sure you have 400ci block in there, what is the casting number on the block ?

How many freeze plugs on the bock ?

PuddleJumper

good point is it realy an 400 you have

Block Casting#

wfo76

What is it, 3 plugs for the 400?

my75baby

Motorhead, yes that was the first thing I checked, the casting # is 3951511, which is a 70-73 SBC 400 ( I also have the scalloped harmonic balancer on the front), and you are correct, I accidentally transposed the flywheel number when i wrote it here, it is 50-6504 like you have said.

Blockman, where does this weight go? if it bolts onto the flywheel, my flywheel is not tapped and threaded for this weight, unless it is a wieght that attaches somewhere else. The weight you are familiar with, where does it go? You have to take out to flywheel to install it? (if so, why not just put the proper flywheel in?)

Thanks again all, you all have great replies and insight, greatly appreciate ALL of your input..

knight37128

http://www.competitionproducts.com/p...sp?number=4162

It bolts between the crank and flywheel.

my75baby

Why, if you have to take the tranny and flywheel out anyway, WHY would you replace the old flywheel, why not for a 20 -30 dollars more just put the 400 wieghted flywheel in?? Is there some reason why you wouldnt do that?

larrywalk

The 400 SBC, which is a GREAT addition to a C3 BTW, is normally externally balanced and requires an external balance at both the harmonic balancer and at the flywheel/flexplate. A few aftermarket rotating assemblies are neutral balanced, primarily with 6 inch rods, which would take neutral balanced flywheel/flexplate and harmonic balancer. Which do you have? Unfortunately, there is not an easy way to find out.

Flywheel/flexplate size - Instead of counting teeth, it is far, far, easier to look at the start mount bolts - if they are staggered, it's a 168 tooth 14 inch dia flywheel; if the bolts are inline, it's a 153 tooth flywheel.

Like many others have said, the easiest solution is to add a balance weight, BUT, this will upset the position of the clutch fingers, and if you can't get enough adjustment, will have to shorten the clutch fork mounting pivot bolt.

On the other hand, get a correct 400 flywheel and it will bolt right in.

If you have a smaller 153 tooth flywheel, like the special high performance engines used, you'll need to go aftermarket.

my75baby

Yes I have the offset starter bolt pattern. I believe it is a 14" 168 tooth flywheel. Also the # off of the tranny is 1304065-903, so as posted I believe this to be a borg warner t-10. So now I will have to start looking for parts. Does anyone know if the flywheel for the stroked 350 (383) is the same as the 400 flywheel?