454 vibrating and breaking starter bolts

[Trevordakid]

The un counter weighted balancer is probably from a small block engine that are internally balanced. A good thing that you found the problem.
I had that exact engine and I remember the balancer along with the countered flywheel.

Ahhhh that’s what I figured. The flywheel has weights on it but the balancer didn’t. So I figured that something was off.

 

[tpenfield]

Do you have a serial number for the engine? I'd double-check the balancer part number, based on the serial number of the engine to make sure you have/get the correct part.

Mark IV 454 must be about 30 years old at this point.

 

[Bondo]

Ayuh,..... 454s are externally balanced motors, you need the weighted balancer,....


I merged yer threads, so posters can find the whole story,.....

 

[Trevordakid]

Do you have a serial number for the engine? I'd double-check the balancer part number, based on the serial number of the engine to make sure you have/get the correct part.

Mark IV 454 must be about 30 years old at this point.

Im going to try and get the serial number tomorrow and get an exact year. Thank you @Bondo for merging.

 

[Trevordakid]

***UPDATE*** I put a 454 harmonic balancer on and it didn’t fit do to the timing plate. I ended up just removing the timing plate and putting the 454 balancer on which was noticeable bigger. I started it up and it was vibrating a lot more…. Starting to think it may not be a 454 after all. 3969854 is the casting number I pulled off the block and it says it could be a 396/402/454. I think my next move is gonna be putting a neutral flywheel on and see how it goes. Any recommendations would be greatly appreciated!!!

 

[Scott Danforth]

may have to pull it apart to determine what you have.

 

[Trevordakid]

Anyone know of a way to tell if it is a 454 or a 402. Front balancer has no weight on it but the fly wheel has weight on it. When I search the casting number it comes up as 402/454 and the same thing with the heads casting number.(3993820) kind of stumped at the point.

 

[Trevordakid]

 

[alldodge]

Anyone know of a way to tell if it is a 454 or a 402. Front balancer has no weight on it but the fly wheel has weight on it. When I search the casting number it comes up as 402/454 and the same thing with the heads casting number.(3993820) kind of stumped at the point.

Think I found it, can tell from the balancer
https://www.chevelles.com/threads/how-do-you-tell-a-402-bbc-from-a-454.71177/

 

[Trevordakid]

Think I found it, can tell from the balancer
https://www.chevelles.com/threads/how-do-you-tell-a-402-bbc-from-a-454.71177/

I reckon I’m gonna have to just swap out the fly wheel for a neutral flywheel and see what happens

 

[Scott Danforth]

Measure the stroke of the piston. 4.00" is 454. 3.76" is 402

 

[Trevordakid]

The moment you have all been waiting for *Drumroll* some dingle berry put the wrong flywheel on. This just goes to show just because they work in a shop doesn’t mean they don’t mess something up every so often. Thanks for everyone’s help.

 

[Lou C]

Glad it was something simple!
“Trust but verify”