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Flexplate question



Well I finally have the 383 in my grubby little hands, now I need a flexplate. The question of the day is which one?

I know to get one for a 400 motor since the crank in the 383 is a 400 crank. But, which tooth pattern, 153 or 168. Then internally or externally balanced? I'm so confused :Silly

I'm asking because I didn't build the motor, I'm not that technical although I can take things apart and put them together I'm just not up on all the motor stuff.


Well-known member
Oct 12, 2000
Hi Scott,
You need the externally balanced flexplate for a 400. Make sure you also have a 400 harmonic balancer, also externally balanced. I prefer the 168 tooth flexplate, more common.



Thanks, exactly what I needed, a nice straight answer. It came with a balancer so I'm all set on that and only have a couple small items that I didn't think about earlier. If all goes well the motor should be dropped in by the end of next week. I finished cleaning and painting the engine compartment and have most of the stuff put back together, this should look awesome when I'm done, plenty of billet parts and other shiny things guys like.

Then it's time to scare all the neighborhood old ladies and kids :Silly


Hey scott

let us know how that 383 goes for you. I was thinking of putting a 383 in the summer. I will be working with a mechanic in the summer and he is going to teach me how to build engines. I have a pretty good idea how but i have just not gotten "my hands dirty" so to speak. Anyways the point is it might be feasible since I might be able to work for parts instead of money. I can afford the top end of the engine but not the bottom, hopefully this job will allow me to get both. I hear they are pretty torquey at the low end but suffer at the top, let us know how it feels to you.

Is it for racing or Fun?

OH on the flexplate does the 153 or 168 matter?

Will the starter gear mesh with either one?

Do you just get a little bit more torque to the teeth with the 168?




I should have it running in 2 weeks if all goes as planned.....notice I said IF. I could take an engine apart and put it together no problem, I just don't understand all the little technical details like choosing a cam, and clearances, etc. This car is strictly for fun, I doubt that taking it to the track would get anything other than bald tires. The motor was built by a friend of mine who had it in his 67, decided he wanted less power, it only has about 100 or so miles on it. I bought a mini-starter that will work with either size flexplate, getting the GM starter in with a heat shield and not scratching the heck out of the headers was all but impossible. Good luck with yours, wish I could have been around when someone he building this motor.

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