The tale of 3 GT500 dampers

[2112]

The base model

https://www.ebay.com/itm/1967-FORD-MUSTANG-SHELBY-GT-500-428-PI-BALANCER/192906160355?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160811114145%26meid%3D8f76249782a8460d8c015f959710c329%26pid%3D100667%26rk%3D7%26rkt%3D8%26mehot%3Dnone%26sd%3D293501849789%26itm%3D192906160355%26pmt%3D0%26noa%3D1%26pg%3D2334524&_trksid=p2334524.c100667.m2042

The restored

https://www.ebay.com/itm/1967-428-GT500-Shelby-Crank-Balancer-Damper-FoMoCo-Mint-Original-Show-Quality/293501849789?hash=item445612d0bd:g:apgAAOSwugJeYZou

The Pookie
https://www.ebay.com/itm/1967-mustang-shelby-gt500-used-428-pi-balancer-original-fomoco-427-side-oiler/333179330869?hash=item4d93092135:g:o2cAAOSwMQ1cD-Lf

[Bob Gaines]

The base model

https://www.ebay.com/itm/1967-FORD-MUSTANG-SHELBY-GT-500-428-PI-BALANCER/192906160355?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160811114145%26meid%3D8f76249782a8460d8c015f959710c329%26pid%3D100667%26rk%3D7%26rkt%3D8%26mehot%3Dnone%26sd%3D293501849789%26itm%3D192906160355%26pmt%3D0%26noa%3D1%26pg%3D2334524&_trksid=p2334524.c100667.m2042

The restored

https://www.ebay.com/itm/1967-428-GT500-Shelby-Crank-Balancer-Damper-FoMoCo-Mint-Original-Show-Quality/293501849789?hash=item445612d0bd:g:apgAAOSwugJeYZou

The Pookie
https://www.ebay.com/itm/1967-mustang-shelby-gt500-used-428-pi-balancer-original-fomoco-427-side-oiler/333179330869?hash=item4d93092135:g:o2cAAOSwMQ1cD-Lf

This is such a predictable story.     Of course Pookies's is bogus. His is a more common 1964 427 balancer. It is missing the champher edges and the machined timing degree marks that the 67 GT500/427 Fairlane version has. His balancer typically sells in the 250-350.00 range.

[gt350hr]

    Pookie BOUGHT that one off of epay last year! It was under $100. I was in on the bidding but got sniped in the last seconds. The rust pitting is HORRIBLE and the fan belt groove needs machining to keep from destroying belts. $750 is ( as usual) a complete rip off!
   Randy

[shelbydoug]

Tlea put one (67 GT500 C6AE) up on ebay last fall. I think the final price was $350? It was just painted Ford blue and he figured what it went for was what it was worth.

It's difficult to find the date code that you need and to find one without hammer marks on them.

I bought a reproduction 66 427 unit from Cobra Automotive. I think it was $350 from them? They beveled the edges for me so it looks like the original 428 PI part, and it's new so no worry about it having been balanced incorrectly in the past.

You can't see the part number on these balancers once installed since they are around the backside of it. It would be the lack of beveled edges that would give the 427 balancer away.


Incidentally, I think it was Prof. Gaines that said that was done to prevent the balancer from machining itself into the top of the front anti-sway bar? Mine's got a very distinctive notch in it from one of the PO. I wonder if he had a 427 in it and didn't know any better?

Here's a picture. Pretty ain't it?

[The Going Thing]

This was done while it was being used on other vehicles (Full-size police cars) I am more inclined to believe it had to do with tooling for the timing marks.  It would make no sense to do the front and rear of the damper for sway bar clearance.  We also see a spacer used at the frame sway bar mount pads on 68 and later FE cars. The 390 damper for 67 is different than the 68 on vehicles.

[Bob Gaines]

This was done while it was being used on other vehicles (Full-size police cars) I am more inclined to believe it had to do with tooling for the timing marks.  It would make no sense to do the front and rear of the damper for sway bar clearance.  We also see a spacer used at the frame sway bar mount pads on 68 and later FE cars. The 390 damper for 67 is different than the 68 on vehicles.

The champered edge will not dig into the swaybar the way the sharp edge design will if it comes into contact.  The balancer would sometimes hit the sway bar when full suspension extension. The problem was eliminated with the redesign of the 69/70 swaybar .  Also the 68 GT500 or KR did not use the 427 style larger diameter dampner . Also 68 was the only year that used the spacers on the sway bar mount and that was only on the CJ cars not the 428 PI GT500 or 390 Mustang. 69/70 390/428 Mustang/Shelby did not use spacers at all.

[The Going Thing]

I have seen many 428PI dampers with the timing marks wiped from the sway bar.

[shelbydoug]

I have seen many 428PI dampers with the timing marks wiped from the sway bar.

I haven't seen many at all. They are pretty rare items. Sometimes it's difficult to come to conclusions on such a scarce part?

[The Going Thing]

I have two here. The reason I was forced to replace swaybar rubbed off most of the timing marks.  The 427 damper I have has no timing marks other than the notch on the pulley and uses a completely different damper. The 428 SCJ damper is slightly narrower than the 427/428PI damper. Ford used sway bar spacers to avoid this issue.  Being we don't have blueprints/engineering information from Ford we'll just have to speculate why only one damper is done this way.

[Bob Gaines]

I have two here. The reason I was forced to replace swaybar rubbed off most of the timing marks.  The 427 damper I have has no timing marks other than the notch on the pulley and uses a completely different damper. The 428 SCJ damper is slightly narrower than the 427/428PI damper. Ford used sway bar spacers to avoid this issue.  Being we don't have blueprints/engineering information from Ford we'll just have to speculate why only one damper is done this way.

No need to speculate. Re read reply #5 . Problem was very bad in 67 . 68 not as much given the smaller diameter dampner . Ford eliminated the problem by changing the design of the sway bar for 69/70 . No issue at all for 69/70 regardless of inf CJ or larger diameter SCJ. 

[The Going Thing]

I am not in disagreement with the fact the swaybar made contact with the damper. I have one to support that. The 68 isn't much that much smaller in circumference. It is almost half the thickness of a PI damper. I have a set of 68 spacers in my Shelby just to avoid the bar wiping the timing marks off again.

[Bob Gaines]

I am not in disagreement with the fact the swaybar made contact with the damper. I have one to support that. The 68 isn't much that much smaller in circumference. It is almost half the thickness of a PI damper. I have a set of 68 spacers in my Shelby just to avoid the bar wiping the timing marks off again.

I am not sure why you disagree with the fact that the swaybar made contact with the dampner given your own words "I was forced to replace swaybar rubbed off most of the timing marks" ? If the swaybar didn't make contact with the dampner how then did the timming marks get "rubbed off". Of course you are welcome to disagree but the evidence on swaybars and PI dampners alike suggest otherwise.

[The Going Thing]

I think you need to re-read what I said. I said the bevel has nothing to do with contact. The bar doesn't make contact at the rear or front edge of the damper. It's almost dead center.

[Bob Gaines]

I think you need to re-read what I said. I said the bevel has nothing to do with contact. The bar doesn't make contact at the rear or front edge of the damper. It's almost dead center.

I suppose how the car is leaning when the suspension is at full travel has a effect on where the balancer can contact the sway bar like when making contact in the middle of the balancer.  I suppose you haven't seen enough different examples otherwise the notches seen worn into the 67 sway bar many times would convince you otherwise. Notches when they happen are the result of the swaybar catching the edge of the balancer. The bevel of course would not help if the swaybar made contact with the balancer in the middle but it would help mitigate the effect some what if the leading edge of the balancer came into contact with the sway bar. Contact at the leading edge is the most common place of contact. All you have to do to confirm is to raise a 67 GT500 up in front with wheels off of the ground and let the suspension sag.Don't ever start your 67 GT500 engine when in the hanging position otherwise you will get a first hand example of the notching effect. The effect is more pronounce if the wrong end links are used and or condition of worn end link bushings . Maybe the bevel was done on both edges for balance. Just what I believe until evidence/information suggest otherwise.

[The Going Thing]

I noted that sitting on jack stands. I agree with yo, Bob. With the risk of full suspension deflection damage to the damper. I utilized the spacers that came out for 1968 to avoid just this issue.