My mechanic installed a 168 tooth flexplate in my 86 Trans Am along with a new 383 stroker and then told me that my present starter would not function with this new flexplate. The flexplate that came out of the car was a 153 tooth part that was attached to the old 350 and was balanced with a weight. Should I go with a 153 tooth flexplate (unweighted) or buy a new starter that matched the 168 tooth flexplate.[IMG]http://[/IMG] [size=3][font=courier new]

What year of block is this 383?? That will tell you what flexplate you need to buy... (whether it is a 1 or 2pc rms)

The block has the 3970010 casting number stamped on it. That is a 1969-1980 350 2 or 4 bolt .

You could get a 153 tooth flexplate from an 82-85 F-body.. That would probably be the best solution if you haven't installed the motor+tranny yet...

I want 168 teeth in order to have enuf leverage to turn over my new 475 stroker.

I don't understand why a flexplate cares if the engine has a one or two piece seal.

And why do some flexplates have weights on them?

Won't work..the flexplate must be counterweighted because it is a 400 crank.

One piece seal has a smaller bolt pattern and will not fit on a two piece crank. I would get a small 153 tooth one with the correct counterweight if possible and use it with a gear reduction starter. The smaller flywheel will help keep the starter closer to the block for better header clearance.

It already has a hamonic balancer on the front. Is that not enough? How would one know where the weight would be positioned?

The correct flywheel will come with the correct weight on it already. Both the flywheel and the balancer are externally balanced, and both are required to be that way or your new engine would shake like a dog sh$tting tacks.

Forgot it was a stroker.. Lo-tec is right...

I have learned alot. I almost had an engine pooping tacks which would have blown either my rear tires or my front tires depending on which gear I was in.

I have a 153 tooth flexplate that came off the old 350 engine and I guess I'll use it. It is weighted and I guess it is fool proof as to where the weight is positioned when bolted to the crank.

Thanks to all contributors.

If it is off of your old motor and it had a 1-piece rear seal, it physically won't bolt on. I looked on summit and couldn't find a 2-piece rear seal 153-tooth flexplate that was externally balanced for a 400 crank. You might have to get both a new 168 tooth flexplate and a new starter. Good luck.

Edit: I don't know if you could have the weight added to a 2-piece rear seal flexplate or not. Another option to look into.

http://www.speedwaymotors.com/produc...o=71&redirect=


sorry about the url size

I asked my engine builder (AR Racing in Sumerduck, Va) about the flexplate and he responded as follows.

400 Ext Bal

I guess this means any flexplate that fits a 400 crank and the flexplate itself must be balanced.

Am I correct?. Does the Externally Balanced apply to the flexplate or to the engine?

1.Incorrect. Any 2 piece seal flexplate will bolt on. You need one specifically for a 400.

2.The flexplate is externally balanced, and in reference then so is the engine.

OK. Now I got it.

All 400 or 383 engines are balanced externally

All 400/383 engines have a weight on the harmonic balancer and must have a weight on the flexplate.

The weight on the flexplate is positioned as there is only one way the flexplate will bolt on.

Only 400 Externally balanced flexplates can be used

There are no 153 tooth flexplates available for the 383/400 engines.

Winna winna chicken dinna!!

You sir are correct

Are there any 153 tooth flexplates for a 383/400 engine. I understand that maybe I would have more room for my headers with the smaller flexplate.

Rook up in rink from chesterfield for seclet message

I really wanted to use a 153 tooth flexplate on my engine so that I could use a starter that would mount closer to the block. My header clearence is very tight. I almost went with one until I noticed my torque converter uses the large bolt pattern (farther outward) With this type of converter, I can't use a 153 tooth flexplate without also changing the torque converter. The large 168 tooth flexplates are normally dual bolt pattern so either converter will work.

Check on Summit and Jegs. Externally balanced 153 tooth flexplates are available for the 400 crank with 2 piece rear seals.

First - you use a flex plate for an auto tranny, you use a flywheel for a manual tranny. Which do you actually need?

As far as availability - call Summit. They have a lot of stuff not in the catalogs.

I got a 153 tooth (which is smaller diameter than the 168 tooth) externally balanced FLYWHEEL from Summit last summer (McLeod brand) for a two piece rear main seal block (my 383). I imagine they would have the flexplate too if you're using an auto.

In my case, the 168 tooth I initially ordered wouldn't even fit inside my T-5 bell housing.

Guess that's what I get for not asking them to begin with, huh? Too ignorant to know the difference at the time, but have learned a lot since then. At least I hope so! Still got a long ways to go though......

Does a used converter pose problems like do they wear out? Or can one buy a damaged one?