I'm in the process of getting my tranny replaced on my 1969 SS 396 camaro convertible. It currently has a 2-speed tranny. Being an automatic my mechanic suggested that I switch the tranny out to a 3 speed. Any thoughts? With the current 2 speed, the car gets off the line well and only pulls 3000 rpms at 70 mph. What should I expect from a three speed? Should I look into a four speed?

I also have a 10bolt (non-posi) rear end. I wanted to upgrade it to a 12 bolt posi, but I'm not ready to write that check just yet. My mechanic suggested that I rebuild my current rear end into a posi rear end. Am I making a mistake by not switching now?

Any feedback would be appreciated.

Chris
Atlanta

 

depends on what gears you have

why not a manual?

 

[X(] well lets start at the beginning the powerglide (2 speed trans) is a racers favorite and ill be damned if i know why(maybe small and lightweight). however if you look at what the big boys run it will usually fall under the more gears the better category. the reason is simple keeping the engine in the power producing range is easier to do with more gears. all transmissions that i can think of have a drive ratio of 1 to 1 in the drive or top gear (powerglide not being an exception) there are some trans in both auto and manual that have a true overdrive in other words something like .75 to 1 ratio. now if your gonna switch transmissions at all, a 3 speed turbo 350 or 400 are great time proven options. however i think another option has risen to a top choice for street and mild to medium race applications. for you its the 700r4 trans(4l60e) for the newer more computer controlled applications. this trans has an ultra low first gear(little over 3 to 1) as opposed to most trans 2 to 1(thereabouts) and a true 4th gear with overdrive. this gets you the best of both worlds in that you can have a reasonable rear end ratio to get a decent launch and yet not have the engine screaming at freeway cruising speeds. this will of course depend on the ratio you chose but it gives way better all around driving. as for your cars rear end you almost cant go wrong with a posi. a ten bolt is plenty strong to handle mild and medium big block buildups. as with most things automotive bigger is usually better (if its truly necessary) so yes the twelve bolt is a good option if you have the $$$ to swap and you think the engine will be producing the power that would make the ten bolt the weak link in the chain. GM thought that a twelve bolt was the way to go for all? big block applications that i can think of if that tells you anything. you can expect your rpm's at 70 to remain the same with any of the 3 speed options. if it were my project id go for the twelve bolt ( unless the 396 was a low to medium hp) throw something like 308 to 342 gears on a posi differential and slap the 700r4 trans in it. this should provide great drag racing capabilities as well as high speed freeway cruising with reliability and strength. there you go thats my two cents any other question send them our way kurt

 

Thanks for the advice. I believe I will take it.
308 rear end 10 bolt (rebuild my old one)
Go with the 700r4
I was quoted around $4k to do the job with a one year warranty? Does that sound resonable?

 

[X(] now dont hold me to my prices but seems a bit high. dont get me wrong i understand its difficult at times to find a shop thats willing to do this type of custom work especially with a warranty to boot!! prices have lots of variables but i should think you should be able to get the trans (including core and install) for around $2000 am i off guys?? the rear should be able to be set up with the posi carrier(stock carrier) around $350-$500 should be less. with an after market carrier probably closer to$750- $1000. i would certainly ask if this guy or shop is willing to install customer supplied parts as thier markup at most shops is 30%-100%. this would allow you to shop online or at jegs, summit etc for trans, diff parts etc. for way less. now a warning on your part is if you supply the parts you will be charged labor if anything needs to come back out to be sent back to the supplier if it dont work right. so i guess you have to decide if its this type of stuff you want to hassle with or do you just want stuff DONE with a warranty. id try to get at least a little bit of cost breakdown so i know why its gonna cost so much and then see where you might save some greenbacks. is the warranty itself costing $$$ or is it that all parts and labor just has a warranty kurt