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FE Power Forums => Non-FE Discussion Forum => Topic started by: Jim Comet on February 21, 2019, 10:35:52 AM

Title: u joint durability?
Post by: Jim Comet on February 21, 2019, 10:35:52 AM

So I am putting together my 66 Comet that will have about 550-600hp. The original big block drive shaft has 1330 ujoints and my new front and rear yokes are 1350. This will be a foot brake bracket car. I would prefer a non drilled joint for strength but there does not appear to be any available with this cap 1330-1350 size setup. Do you see any problems with running a Spicer 5-648x conversion u joint at this hp level? I would upgarde drive shafts but the money pit is hungrier than my wallet right now. Anyone racing with 1330 joints? Should I be concerned? Thanks for your advice. Jim

Title: Re: u joint durability?
Post by: 57 lima bean on February 21, 2019, 01:16:35 PM

Raced my car for years with 1330's.Foot brake with an auto...no issues.

Title: Re: u joint durability?
Post by: TomP on February 21, 2019, 05:47:11 PM

My Fairlane uses that U joint at the front because it has a Mark Williams 1350 slip yoke but runs the stock 1330 series Crown Vic driveshaft and the rear U joint that comes in it.

Title: Re: u joint durability?
Post by: manofmerc on February 22, 2019, 05:23:55 AM

On my 67 comet it runs 6.80-7.00 460 power with the same setup you are speaking of c-6 with a transbrake no problems so far .I do have an ford motorsport yoke and I had a driveshaft shop build my drive shaft so I have solid u joints and a bit thicker tube .Good luck Doug

Title: Re: u joint durability?
Post by: Falcon67 on February 22, 2019, 09:48:51 AM

Footbraker here too.  Stock driveshaft, 1330 front, converter joint in the rear to hook up the 9" yoke.  I haven't looked at them in 18 years.  Car has run as fast as 7.0x over the years.  As above if crossing under the 7.0 mark, have a local build a good driveshaft.  If I pulled the 570 HP motor out of the dragster and dropped it in the Falcon, the next thing would be to replace the stock shaft. 

Title: Re: u joint durability?
Post by: Barry_R on February 22, 2019, 08:57:05 PM

Back many years ago I ran the conversion joints without any problems in a 12 second car.  I was "instructed" to clock any grease fitting so it would be "under compression" as the driveshaft was loaded.  I stepped up everything after I acquired a nitrous habit so I cannot attest to u-joint durability at higher power levels - - because it broke pretty much everything between the flywheel and the lug nuts......