383 harmonic balancer per JTR

[Forces]

The 383 is externally balanced, so I need to run a harmonic balncer on it. In the JTR manual, it mentioned using a 7.25" balancer or smaller. I have an 8" on my engine. I went to drop my engine yesterday, and I now see why you can't use the 8". It wouldn't clear the steering rack. I went to NAPA to get a smaller one and they couldn't help at all. The only ones that are <7.25" are for 3.8L v6's. ....Will that even work? Is there a year/model GM car that has a stock harmonic balancer that will work?

[SHAI]

it mentioned that you will have to use a 6.6" balancer with a 400 sbc. Where would you get a 6.6" balancer?

[dr_hunt]

To use one that small on a 400sbc I think you'll have to be internally balanced then use the 6.25 inch one. That's what I do, works for me. Wrong, I found that summit makes a balancer that is 6.6 inch for the 400 crank.

[jnjdragracing]

I bought one from ebay, user name was dirttrackthunder. It is a small balancer external balanced. I ran it for about 2 years with no problems. I was turning about 6500 rpms in my 412 cu. Check them out.

 

John

 

The 383 is externally balanced, so I need to run a harmonic balncer on it. In the JTR manual, it mentioned using a 7.25" balancer or smaller. I have an 8" on my engine. I went to drop my engine yesterday, and I now see why you can't use the 8". It wouldn't clear the steering rack. I went to NAPA to get a smaller one and they couldn't help at all. The only ones that are <7.25" are for 3.8L v6's. ....Will that even work? Is there a year/model GM car that has a stock harmonic balancer that will work?

[Forces]

To use one that small on a 400sbc I think you'll have to be internally balanced then use the 6.25 inch one. That's what I do, works for me. Wrong, I found that summit makes a balancer that is 6.6 inch for the 400 crank.

 

I was under the impression that 383s and 400s couldn't be internally balanced......?? at any rate, if it was internally balanced, could you then run a dampaner designed for an internally balanced engine?

[jnjdragracing]

Yes, my old 406 was internally balanced. We then could run a 350 balancer and flywheel.

 

John

 

I was under the impression that 383s and 400s couldn't be internally balanced......?? at any rate, if it was internally balanced, could you then run a dampaner designed for an internally balanced engine?

[280zwitha383]

I bought one from ebay' date=' user name was dirttrackthunder. It is a small balancer external balanced. I ran it for about 2 years with no problems. I was turning about 6500 rpms in my 412 cu. Check them out.

 

John[/quote']

 

I have the same one on my 383. Works well.

[dr_hunt]

I have internally balanced sever 400's just to get away from the external balancers, besides, you can tell everyone it's a 350 and they'll never know.

[jakeshoe]

I have internally balanced sever 400's just to get away from the external balancers, besides, you can tell everyone it's a 350 and they'll never know.

 

Unless they look at the block, the bulges around the cylinders that are identifiable from the top, usually the 3 freeze plugs or bosses on the sides, many 400's also have a distinct pattern on the front of the block of casting circles.