new driveshsft and slip yoke

[msbaugh]

I put my old 741 8 3/4 chunk in my challenger (this is temporary until I get my 489 gear ratio changed).  When I pulled the drive shaft I noticed the rear loop of the drive shaft around the u-joint end cap is almost completely cracked!

It has 7260 u joints on the front and rear yokes. This is a 3500 lb 440 making pretty good power. I'm going to get the drive shaft fixed and converted or get a new one made with either 7290 or 1350 u joints. The 489 3rd member I'm working on currently has a 7290. Should I just buy a 7290 slip yoke and stay with all 7290 joints in the new conversion or buy a new 1350 slip yoke and convert on the rear with a combo 1350/7290 to the 489? I'm trying to save $$, so is the 1350 really worth it? I don't want to have to change the 7290 489 pinion yoke unless I really should

[Chryco Psycho]

the 7290 should be easily adequate unless you are running drag slicks & ladder bars , mine with 7290 joints lasted 9 seasons on slicks & ladderbars pulling the front wheels 2' on every pass

[msbaugh]

Well I'm going 7290 all the way! Saves me some coin! Bought a stock replacement 7290 slip yoke from dr. Diff. No one makes a forged piece so this will just be a stock cast replacement. Hopefully it holds up well behind the 440!

[msbaugh]

Will a 3 1/2" mild steel driveshaft with .083" walls rather than .06 kill acceleration with the extra weight? The local driveline shop doesn't work with aluminum or chrome moly

[Chryco Psycho]

all mass will eat power trying to accerate it , but I doubt you would feel the difference unless you were in a light racecar & timing every pass