Ok. Keeping in mind my car is TPI and stops pulling at 5 grand and I usually shift at 4500 and I want to run a 12 flat some day what size gear should I get. I think I need to be able to go 110mph to get a 12. This must be done by 5 grand or I'll be over revving and not making any power do to running out of gear. I have a 3.08 and Its not to bad but I definatly need a bigger gear. The guys at my work have all had carbed cars that they rev to 6500 or higher so there like, "Man get a 4.11 or higher but atleast get a 3.73!" According to the gear calculator with a 3.42 at 5 grand its 112mph and a 3.73 at 5 grand its 102. I'm not going to throw the thing in 5th so should I go with a 3.42? Thanks alot but I just cant decide.

 

Ok I have another really stupid question. I drive my car maybe 2 nights a week and when the track opens I'll go once a month atleast. I'm expecting someone to respond all mad and telling me I'm stupid but what would a spool act like in my car? The stock posi does a one wheel on dry when turning right but is completely posi when going straight or left. I want something that wont do a one wheel and I dont want to spend a lot. Would a spool make the car hop really bad and make it want to push really bad or only moderatly? I know that it might make it want to kick out but I have no problem holding it sideways and I wouldnt drive the car in rain or snow. I will be getting drag radials pretty soon so that might make a difference. Any suggestions on what to get besides a spool? I dont want to spend more that $300 on a diff and like I said it better never do a one wheel at all... Thanks guys! Reall really apreciate your help!

 

if you want to make your posi work like an open rear continue to spin the tires while turning. a spool isn't streetable. you need to make more power or lose weight reguardless of what a calculater says you aren't going to make 5000 rpm in drive through the traps in a 1/4 mile. you aren't going to run 12s anything with a stock or mostly stock tpi

 

I have a 3:73 and a locker. I love the locker and will never use a clutch or cone type posi again. A lot of people don't like the lockers. Its all personal preference. Mine never does a one wheel peel, never makes any noise, and I have never had wheel hop in a turn. I got mine for $50.00 on ebay.

From what I have heard others saying about TPI, you may not want to run any more gear than a 3:42.

Check out these ebay auctions;
Item number: 2453397816
Item number: 2454020020 This is the same unit I have.

 

So you think I'm on the right track with a 3.42? I want to get a Moser 12 bolt as soon as I can save up the money so maybe I'll just put a gear in my rear for now and leave the posi alone. If the car ever starts doing a one wheel I always let off right away.

 

I myself like the 3:73. But it was too much gear for the stock carbed LG-4 305. A 3:23 would have been better for it, but I chose the 3:73 because I was installing a 355 with a semi-ratical cam down the road.

From most of what I have read on these boards, if you have a stock 350 TPI, you don't want anything lower (numericaly higher) than a 3:42. If you don't install a posi or locker with a lower gear you will probably easily do a one wheel peel a lot. So keep that in mind.

My situation is a little like yours. I installed a lower gear and a locker (in your case you might choose a posi) just to get me through till I can afford the 12 bolt or 9". I would seriously look at getting a limited slip of some sort when you install the gear in your 10 bolt or you will probably be dissapionted with the lack of traction. It won't cost much more in labor to install it.

When I installed the 3:73 and the locker, the stock LG-4 could smoke the tires through first gear on dry pavement, and sometimes a little into second.

I have a Gov-Loc. They are not as strong as a good posi, and are prone to breakage when used with high horse power, and big tires. But I only drive my car on nice weekends and have not gone to the track yet. I put maybe 500 miles on it in the last year and a half. The Gov-Loc was a fine choice for me because it will last until I get my 9" Ford rear end.

As far as the 3:42 for your set up, it would probably be the best choice.