sbc harmonic balancer

[Adger Smith]

Bobby,
In your better terms, yes you can use different parts from SBC's to make them "Hybrids". The late mod crank is keyed the same as the early mod crank as far as I know. the cam timing would be different, too. The number of degrees difference in the mark is in the balancer. I thought it was more than 10 degrees, like 26 for one series balancer and 13 for the other. My memory tells me there are actually 3 different timing combos (locations) for a SBC without the LT-1 and LS. As to the use of the balancer. Yes, you can use it, BUT and that is a big But... It might cause some of the symptoms mentioned in some of the other posts. That balancer you are talking about was designed for the harmonics of the 3" stroke 283 crank and was also used on the low RPM (Low PERF) 307/327's. If this is just a "driver" and not a race car that is going to see some 5,000-7,000 RPM blasts it might survive and your other parts might survive as well. If you want a better stock balancer there is a heavier, extra wide 305 balancer that is about the same diameter as the 6 3/4. I think it will match up to your timing mark, too. That timing mark on your cover is straight down from the top, behind the water pump. You do realize you MUST use a long water pump to see that mark? I think It is about 6 7/8" diameter. From Pioneer they are pretty cheap and I think Powerbond makes a better replacement that is a little higher priced. I know we are talking about a balancer that is NOT Aluminum. How did we get to talking about them? I thought everyone knew the aluminum weren't even good paper weights or doorstops. OK, ash trays! :~)

[Dave Casey]

I believe that the balancer that I used on my 305 stocker for years is the one you are refering to. It worked fine for me for 20 years, it is a narrow balancer. It would probably still be on my car, but I believe g/s and faster requires an aftermarket balancer and I put one on.

I always assumed that the rear of a one piece seal 305/350 crank is balanced externally, but the front was not. Is that correct ?

[Rob Petrie E395]

Did I screw up when I ordred my Damper? ATI has several available for my engine (Late Model LT1) My thought was the less weight on the crank the better for performance. So instead of getting the 7.53 inch steel one I got the 6.78 inch Aluminum one. The steel one weighs 9.75 Lbs. the one I got weighs 4.5. I figured that much weight had to be worth something in terms of performance. Should send it back and get the steel one? Or is the Alum ATI super damper as good as the heaver steel one they sell? Thanks

[Alan Roehrich]

Rob, I run the lightest aluminum damper ATI makes on my big blocks, you'll be fine.

It isn't the aluminum that makes those old hubs bad, it's the fact that they are not dampers at all, but rather just a hub to bolt a pulley on, and stop the front cover from leaking.

[Adger Smith]

Correct Dave.
The flywheel on the one piece crank is smaller on the hub and has a smaller bolt circle it also has what is called a "Butterfly weight"
That weight replaces the "Ear" that is on most 2 piece seal cranks out side the seal surface. That ear is usually weight that is in line with the rear counterweight. The ear is cut off on the 1 piece cranks. They are full round in that area.
The balancer end of the crank is neutral balanced.
Rob the small is OK

[Rob Petrie E395]

Thanks guys. While this engine will not by any means be the fastest one out there. I dont need to tear it up with a foolish mistake. Thanks again