What are most guys running in high ten second cars on slicks with a 12 bolt? I mean in a heavy non stripped Skylark or GS. [3800-3900 lbs]. I have a Chevy posi with what are supost to be the stronger Eaton spider gears. I also have Yukon replacement axles with Mark Williams C clip eliminators. I bought a new girdled cover for it also. With my old motor and low 1.5 60 fts with a best of 1.489 it has been holding so far. I have some better heads and might go to a better matched cam to my car and most tell me that it should make it into the tens if it runs the way it should. The car is mostly drag with little street use. I don't want to be crossing my fingers on every run wondering if the rear is going to hold or not, makes it hard for me to do a good driving job. I have had one Buick racer with a fast heavy car tell me I need a spool, I belive he is probably right but just want to take a little pole to see what others are running. Thanks, Tom
Spool Hi Tom, I think dipping into the ten's is a good time to start thinking hard about a spool. Although I don't advise doing so, I've been running on on the street for a couple of years now without a noticable problem. If you drive CAREFULLY and take wide turns when possible, it's tolerable. It is tough on axles though. If you want to take the jump, I'll be taking the spool out of my car sometime early this spring. I'll be selling the spool and the 4.10 gears. If you're interested let me know. Steve
Tom, How much street driving do you do? Sounds like it time for you to decide is you want a street car or race car. You get to a point where they just dont mix anymore. If its just a blast now and then down the street, put the spool in. If its more street driving that that, you wont like the spool too much and you will break axles.
You nailed it Jeff, Every year it it is less steet car and more race. I had the roll bar laying in the garage for 3 years before I put it in. Then I started running 11:40s and 11:30s so I put it in before they made me put it in. Our track is faster than 11:50 and it needs a roll bar but yet I know of at least one car at 11 flat without one so I guess it depends on who you are :Brow: Also with the cylinder head switch I don't know if it will run on pump gas on the street because my compression will be up allot. I am sure it won't with the 105a cam because it makes allot of cranking compression. Maybe if I clean up the chambers and with a later closing intake valve cam I might get by. I am also thinking of battery and a fuel cell in the trunk so more race car stuff. If I do that the back seat would go also because with the roll bar maybe a small child might be able to crawl in back there. I just have it in there for the street car look. Steve, I am very interested in the spool if it is for stock spline axles. I have Yukon replacement axles in it now. I don't think they are a full tilt race axles but they are much heavier than the stock axles. I have Mark Williams C clip eliminators also. After the old GM 4.10 gears broke I got a new girdled cover for it also. The car has been up on stands with the rear end apart for over a year now so waiting a little longer for the spool is no problem. I will PM you about a price and such stuff. I blew apart the old original spider gears right on the line in 5 runs after I got my 60fts into the high 1.5s. It had been running for years at 1.62-1.65 60 fts. Anyway the noise when that posi let go scared the hell out of me. It sounded like a gun went off in the car, it happend right at the hit of the gas, it had moved enough that I coasted off the track into the grass next to the tree in case it was dumping oil out of some place. I after some quick checking I came down to something in the rear end let go. I was still running a ring gear spacer at the time, I figured it sheared the bolts off. The spacer and bolts were fine, the posi gears and springs and plates were in a million pieces though. The posi let go before the stock old 12 bolt axles did which suprised me also. Anyway that bang it made when it broke scared me so bad I cringe every pass down the track since then even though I have had the rear apart a couple times since updating to better parts and it all looks fine. I have made many trips down the quarter mile in different cars and never had a major problem. I am getting to feel gun shy because I wonder when my time is coming. The thought of going faster just makes that feeling worse. Don't get me wrong, I love to play with different stuff to see if cars goes faster but I never dreamed back in 1993 when I first ran a 14:90 something with a stock low comp 455 on street tires that I would be talking about maybe high tens with that same car today. It wasn't just to many years ago I said if I could run high 11s on a hot day and crappy track I would be happy, but now I am getting goose bumps just thinking about my first 10 second time slip. So just for the piece of mind I think a spool would be the way to go. I have enough stuff here I can put together a stock 12 bolt posi I can put in if I ever want to do some street driving more than just a trip down main street. I am sorry, another of my long rambling posts. Tom
Hello, I want to thank Steve Reynolds for offering me the gears and spool he has. It will be one less thing to worry about breaking by going with a spool. Is it true that no hop bars become a bad thing at some point? I don't think they made my 60fts better but it has more consistant 60 fts with them on. I didn't like them with stock upper arms but after I made some arms from roll bar tubing and with a 3/4" hiem joint on each end it freed up the suspension allot and it works much better. This spring I want to make new lower arms with hiem joints too.
Yes very true and I can vouch for it. My car with the old 462 hooked on ice with the bars. Put the new engine it and it was like I was on ice and that was with new slicks. The back of the car would jump off the ground and buck so violent it tripped my battery kill switch on one pass, thought the engine blew up. :ball: The track anouncer thought I was a real sport when I pulled to side of the track immediatly. Sure was glad the oil wasn't pooring out.
I was Runnig 10.20's with a eaton posi 1.42 short times but would eat up a set clutches pretty quick and it started spining only one tire put an spool in it it hook better but like jeff said the rear of the would hop of the ground and have tire shake and broke the ring gear ( that i have just found last week three teeth broken )
Thats what happened to mine the last time it ran 2 summers ago. It rattled the tires but seemed fine until I got into high gear and the car shook so bad I thought I had a tire about to come apart. I found part of a tooth broke off the ring gear but so far I can't find out why it shook so bad. I can't find anything bent or broke, tires all look fine. I am wondering if the broken tooth could have made it shake so hard. It didn't break the whole tooth off though so it still had something there in that spot. I have not run the car since that day. I would hate to get it all back together again and have it shake bad on its first run and waste a whole weekend. I would have to go to different upper arms to get rid off the no hop bars. But with the heim joints I can drill another set of holes in the no hop bars just above the rear end ears to take alot of the angle out of them. I wonder if that would be enough?
Were you guys running pro-gears when you broke them? I've heard that the pro-gears are softer so they are better on the track but they don't like alot of street driving because of the heat cycles. Downside of street gears is that they are more brittle so they cannot take the track abuse. What to do? o No:
I had a really old set of factory GM 4.10s that were dated 1969 I think they were. I ran them in my car for probably 5 years. I didn't have any rear end problems with a totaly stock well worn 12 bolt till my 60ft times got into the high 1.5s, then the old antique spider gears blew up. They were the weak 18-10 spiders so they held up pretty good for alot of years. This was with 60fts in the mid to high 1.6s. I beefed up the posi with some new eaton 17-10 spiders and it was ok even at a couple of 1.48- 1.49 60fts, then it rattled the tires pretty hard and thats when the old ring gear let go. Perry C. told me the other day he runs the street gear in his yet, I don't know what his 60 fts are but I bet they are pretty dam good, I think he said he replaces the gears in his car every 50-75 runs, I need to double check on this but I am pretty sure that was what he told me. I think he is in the 9s now so he would know about what it takes to make a 12 bolt live. I think he still has a 12 bolt anyways, Maybe if Perry reads this he can straighten out what I said if I got it wrong. Sorry Perry if I talked out of turn. I didn't have any problems with the posi clutches after I started shimming up the posi real tight. I had it so tight that the street tires would sometimes chirp going around tight corners slow. Maybe that had some to do with killing the spider gears also. I was going to put in a set of the thick plates and the real heavy posi springs like the brute strength posi has this time and loosen up the spiders just a hair. I have lines on a couple of used spools now so I am going that route this time. So it was bound to happen for me sooner than later for those gears to finally die. I have read and been told that Richmond street gears are softer than original GM gears were so maybe if I had some new street gears it would not have broke. I also think how the gears are set up has allot to do with how much abuse they will take. If the drive side pattern is a little toward the outside end of the ring gear teeth I think that it will snap off the outside end of the ring gear tooth easier than if the pattern favors the inside end of the ring gear teeth. I don't know this for sure but its my idea on setting up gears. I have also been told to keep the end play on the tight side for drag racing since the gears try to push away from each other under heavy load, and the pattern will move out on the ring gear teeth also under heavy load.
