POSI vs SPOOL

Adger Smith · 07-28-2011, 08:42 AM

Way back in the real early 70's I ran a 69 Z-28 in stock. Remember this is with 7" tires. We noticed the et's would vary just a little with the posi. I think that was slip, but the posi always ran more MPH. So we didn't cheat with the spool. We did break a lot of spider gears and cross shafts until I shimmed the clutch pack extra tight and ran the service pack HD springs. The stock springs would come out and be bowed (if they werent chewed up) like the forces of RPM got to them. I think the extra MPH was due to the slip in the posi when there was un even tire growth. Most of the time I ran the Firestone tire on a skinny wheel and they grew a bunch. The only problem we had with axle's was the outer beraring going out and chewing up the hardened surface of the axle. We had a side gear or two break and chew up the axle splines. I think the Mopar axel bearings are not like the Chevy 12 bolt and you would not have that problem. You would not have the problem of the axels floating side to side and breaking the spiders and cross shaft. I had to do alot of work and buy alot of parts to keep the posi alive. With the rules today I agree with the statement about what weighs less...besides, a lite spool is trouble free.
Dwight, What did you guys do?

07-28-2011, 08:42 AM	#4
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: POSI vs SPOOL Way back in the real early 70's I ran a 69 Z-28 in stock. Remember this is with 7" tires. We noticed the et's would vary just a little with the posi. I think that was slip, but the posi always ran more MPH. So we didn't cheat with the spool. We did break a lot of spider gears and cross shafts until I shimmed the clutch pack extra tight and ran the service pack HD springs. The stock springs would come out and be bowed (if they werent chewed up) like the forces of RPM got to them. I think the extra MPH was due to the slip in the posi when there was un even tire growth. Most of the time I ran the Firestone tire on a skinny wheel and they grew a bunch. The only problem we had with axle's was the outer beraring going out and chewing up the hardened surface of the axle. We had a side gear or two break and chew up the axle splines. I think the Mopar axel bearings are not like the Chevy 12 bolt and you would not have that problem. You would not have the problem of the axels floating side to side and breaking the spiders and cross shaft. I had to do alot of work and buy alot of parts to keep the posi alive. With the rules today I agree with the statement about what weighs less...besides, a lite spool is trouble free. Dwight, What did you guys do? __________________ Adger Smith (Former SS) Last edited by Adger Smith; 07-28-2011 at 08:48 AM. Reason: sp