Forces Posted September 18, 2006 Share Posted September 18, 2006 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? Quote Link to comment Share on other sites More sharing options...
SHAI Posted September 18, 2006 Share Posted September 18, 2006 it mentioned that you will have to use a 6.6" balancer with a 400 sbc. Where would you get a 6.6" balancer? Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted September 18, 2006 Share Posted September 18, 2006 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. Quote Link to comment Share on other sites More sharing options...
jnjdragracing Posted September 18, 2006 Share Posted September 18, 2006 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? Quote Link to comment Share on other sites More sharing options...
Forces Posted September 18, 2006 Author Share Posted September 18, 2006 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? Quote Link to comment Share on other sites More sharing options...
jnjdragracing Posted September 18, 2006 Share Posted September 18, 2006 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? Quote Link to comment Share on other sites More sharing options...
280zwitha383 Posted September 18, 2006 Share Posted September 18, 2006 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. Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted September 18, 2006 Share Posted September 18, 2006 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. Quote Link to comment Share on other sites More sharing options...
jakeshoe Posted September 18, 2006 Share Posted September 18, 2006 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. Quote Link to comment Share on other sites More sharing options...
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