Moparts

Will this gear be right for me?

Posted By: bigsbigelow

Will this gear be right for me? - 01/06/11 06:03 PM

My Duster ran a best of 12.67 at 107 mph with a 1.9 sixty foot last summer. I want to optimize my combo during the off season. Currently the car has a 741 case with a broken Sure-Grip and 3.91 gear (Found out the Sure-Grip was broke at Milans all Mopar day. Embarrassing to say the least). I am definitely going to upgrade to a 742 case with a spool. I want to turn 6500 rpm through the traps and I run a 27" tall tire. I am thinking 4.30's will be good. You guys have never steered me wrong so I thought I would consult the experts before I made a move.
Posted By: Slingshot383

Re: Will this gear be right for me? - 01/06/11 06:05 PM

4.30's or 4.56's will work, what engine, what cam type (it makes a difference), what transmission?
Posted By: bigsbigelow

Re: Will this gear be right for me? - 01/06/11 06:12 PM

It is a 340 with a Comp Cams Xtreme Energy XS282S (.520 / .540 lift and 244 / 252 duration at .050) and 10.5:1 compression. The trans is a 727 with stock gears and a 9.5" PTC 3500 rpm converter. I do a lot of street driving with the car as well.
Posted By: Get-X

Re: Will this gear be right for me? - 01/06/11 06:16 PM

Quote:

It is a 340 with a Comp Cams Xtreme Energy XS282S and 10.5:1 compression. The trans is a 727 with stock gears and a 9.5" PTC 3500 rpm converter. I do a lot of street driving with the car as well.



I would be using a 4.10 if it were mine.
Posted By: MR_P_BODY

Re: Will this gear be right for me? - 01/06/11 06:19 PM

Here's a handy calculator BUT remember to add in the
converter slippage
http://www.richmondgear.com/01calculators.html
Posted By: earthmover

Re: Will this gear be right for me? - 01/06/11 06:28 PM

when i ran my 340 last yr i had 28/10.5 slicks and 4.57 gears and would turn 62/6300 in the 1/8 mile so i think 4.30 would be better in your case jmop mike
Posted By: Get-X

Re: Will this gear be right for me? - 01/06/11 06:33 PM

Quote:

when i ran my 340 last yr i had 28/10.5 slicks and 4.57 gears and would turn 62/6300 in the 1/8 mile so i think 4.30 would be better in your case jmop mike



I agree that the 4.30 is the best gear at the track, but they aren't great for street use. If the car is mostly a drag racer and only occasionly sees the street, than the 4.30 would be perfect. If it's mostly a street car that goes to the track once or twice a year use the 4.10 IMO.
Posted By: Mr340

Re: Will this gear be right for me? - 01/06/11 06:48 PM


I have a 4.30 with 28" tires in mine now and while it's great at the track I'm thinking of swapping it for a 3.91 to enhance my street driving.
A 340 will love the gear, i now have a 416 so I think I can use abit less gear.

Gary
Posted By: bigsbigelow

Re: Will this gear be right for me? - 01/06/11 07:01 PM

Quote:

Quote:

when i ran my 340 last yr i had 28/10.5 slicks and 4.57 gears and would turn 62/6300 in the 1/8 mile so i think 4.30 would be better in your case jmop mike



I agree that the 4.30 is the best gear at the track, but they aren't great for street use. If the car is mostly a drag racer and only occasionly sees the street, than the 4.30 would be perfect. If it's mostly a street car that goes to the track once or twice a year use the 4.10 IMO.



I guess I should mention that I can tolerate losing some "street-ability" for a faster car. There is a group of tuner guys that I am friends with. I want to be able to inch them out at the track with an all motor combo. 12 flat is the fastest car in the group. I think i can reach that with the correct gear.
Posted By: earthmover

Re: Will this gear be right for me? - 01/06/11 08:18 PM

4.30 i've got a buddy that loves them and they work great for him and he drives it alot ..i have even drove my little mess a few times and it didnt bother me at all never ran hot but its all in what you will live with and what you would like to do with the car....
Posted By: aquamist60

Re: Will this gear be right for me? - 01/06/11 08:51 PM

Last year we ran a 340 Duster with 28" tall slicks & a 4:56 gear. Had a best 60' @ 1.68, 1/8 mile 7.71 @ 90.98 mph, 1/4 mile was a 12.19 @ 109. Shifted @ 6200 & crossed the line @ 6500 rpm.
It's mostly a stock short block with stock iron heads. I'm thinking we've still got about another .3 in the 1/4 left on the table.
Posted By: forphorty

Re: Will this gear be right for me? - 01/07/11 01:32 AM

If your stall speed is really only 3500,I think a looser convertor (4500ish} would pick up more than any gear change.
Posted By: BSB67

Re: Will this gear be right for me? - 01/07/11 01:36 AM

Not to be Debbie Downer, but you'll need to find more hp to go 12.0 or faster, the 107 mph indicates not enough hp.

Be sure to check with guys running a spool on the street, as some don't like it.
Posted By: bigsbigelow

Re: Will this gear be right for me? - 01/07/11 03:20 PM

Quote:

Not to be Debbie Downer, but you'll need to find more hp to go 12.0 or faster, the 107 mph indicates not enough hp.

Be sure to check with guys running a spool on the street, as some don't like it.



You don't think so? That 107 mph was at 5800 rpm. That is why I want a gear change. Shoot, I shift higher than I trap. I have also driven a couple cars with a spool. I can definitely notice the difference but it doesn't bother me.
Posted By: Kindafast

Re: Will this gear be right for me? - 01/07/11 05:28 PM

I would stay away from the spool unless you have some good axels. A good sure grip would be better suited for a strip street car.
Posted By: 440Jim

Re: Will this gear be right for me? - 01/08/11 03:51 PM

Quote:

If your stall speed is really only 3500,I think a looser convertor (4500ish} would pick up more than any gear change.

Posted By: BSB67

Re: Will this gear be right for me? - 01/08/11 08:04 PM

Quote:

Quote:

Not to be Debbie Downer, but you'll need to find more hp to go 12.0 or faster, the 107 mph indicates not enough hp.

Be sure to check with guys running a spool on the street, as some don't like it.



You don't think so? That 107 mph was at 5800 rpm. That is why I want a gear change. Shoot, I shift higher than I trap. I have also driven a couple cars with a spool. I can definitely notice the difference but it doesn't bother me.



No, I don't think so. We've done this a few times and when nothing else is changed, and you adjust appropriately for atmospheric conditions, it might be 1 mph. And if you go with the gear that gives you the very best et, you might be down a little in mph. Going to a spool might few up a few ponies - I don't know.

Try it and report back. It's always good to have data from well controlled test conditions. It will be quicker. And if I'm mistaken, I'd like to know that too.
Posted By: earthmover

Re: Will this gear be right for me? - 01/08/11 08:19 PM


Loc: Ohio Re: Will this gear be right for me? [Re: bigsbigelow]
#6401288 - Thu Jan 06 2011 02:51 PM Edit Reply Quote Quick Reply



Last year we ran a 340 Duster with 28" tall slicks & a 4:56 gear. Had a best 60' @ 1.68, 1/8 mile 7.71 @ 90.98 mph, 1/4 mile was a 12.19 @ 109. Shifted @ 6200 & crossed the line @ 6500 rpm.
It's mostly a stock short block with stock iron heads. I'm thinking we've still got about another .3 in the 1/4 left on the table.


my 340 was a little more then stock about 11.1 comp. and 520/540 soild cam mild heads but ran a best of 7.44 at 89.9 with a 1.67 60' which was not the best 60' i think it had more in it with some frontend workand a new set of slicks ( check holes was gone on the set i had) but ill never know i sold the short block...your mph is better with about the same 60' so hard to say...but i think the 4/30 is a preety good gear as well. mike
Posted By: Cab_Burge

Re: Will this gear be right for me? - 01/08/11 08:32 PM

Quote:

My Duster ran a best of 12.67 at 107 mph with a 1.9 sixty foot last summer. I want to optimize my combo during the off season. Currently the car has a 741 case with a broken Sure-Grip and 3.91 gear (Found out the Sure-Grip was broke at Milans all Mopar day. Embarrassing to say the least). I am definitely going to upgrade to a 742 case with a spool. I want to turn 6500 rpm through the traps and I run a 27" tall tire. I am thinking 4.30's will be good. You guys have never steered me wrong so I thought I would consult the experts before I made a move.

Fix the posi first Once that is done make your decesion I would look at two third members, one for street and one for racing as far as the right ratio and finish line RPM find out where the car likes being shifted out of first and second gears by looking at the 330 and 660 ft. times and MPH Most stock lie SB like being shifted around 6300 to 6700 RPM, the steeper rear gears will help it some on the top end but they are not a cure all Maybe 9secondPhil will chime in on his fisrt "Cab" car and the results of changing the rear gears from 3:55 to 4:89, not much if I'm remembering correctly
Posted By: bigsbigelow

Re: Will this gear be right for me? - 01/10/11 12:51 PM

Thanks for all the insight guys. I was thinking gear change because I wanted to get rid of my 741 case. I have read and heard some bad things about the 741. Is it all that bad? If not, I will just rebuild the sure-grip and save some coin.
Posted By: Labratt

Re: Will this gear be right for me? - 01/10/11 05:56 PM

Ryan..you don't need a spool! I've never ran one with my 440 GTX,and you know how that runs at the track..and on the street! My friend Bill,who owns Warren Gear and Axle,set mine up about 3 yrs. ago..still in one piece! And I don't BABY my drivetrains! My carrier is an old style from the early 60's with a clutch-plate type set-up. LOVE it! I run a 4:56 Richmond gear with 30" tall slicks..and street tires. My engine makes peak power at 6,000 rpm..through 1/4 traps at 6500-6600rpm..right where I want to be, 10% over peak! I think if you run a 27" tall tire,a 4:30 might be a little steep for the street! I've got a "spare" 489 case 4:10 gear,also set up by Bill,sitting in my pole barn..but I need to hang onto it..JUST IN CASE! If I were you,I'd give Bill a call..just don't mention my name..he might charge ya' double! ...J/K! He's a GREAT guy..and knows what the heck he's doing! My GTX is proof of that! Best of Luck on whatever you decide! Let me know what that is! Thanks! Randy
Posted By: bigsbigelow

Re: Will this gear be right for me? - 01/10/11 06:19 PM

Quote:

Ryan..you don't need a spool! I've never ran one with my 440 GTX,and you know how that runs at the track..and on the street! My friend Bill,who owns Warren Gear and Axle,set mine up about 3 yrs. ago..still in one piece! And I don't BABY my drivetrains! My carrier is an old style from the early 60's with a clutch-plate type set-up. LOVE it! I run a 4:56 Richmond gear with 30" tall slicks..and street tires. My engine makes peak power at 6,000 rpm..through 1/4 traps at 6500-6600rpm..right where I want to be, 10% over peak! I think if you run a 27" tall tire,a 4:30 might be a little steep for the street! I've got a "spare" 489 case 4:10 gear,also set up by Bill,sitting in my pole barn..but I need to hang onto it..JUST IN CASE! If I were you,I'd give Bill a call..just don't mention my name..he might charge ya' double! ...J/K! He's a GREAT guy..and knows what the heck he's doing! My GTX is proof of that! Best of Luck on whatever you decide! Let me know what that is! Thanks! Randy



Thanks much for the info Randy. Looks like I will be making a phone call.
Posted By: Get-X

Re: Will this gear be right for me? - 01/10/11 06:34 PM

Quote:

Ryan..you don't need a spool! I've never ran one with my 440 GTX,and you know how that runs at the track..and on the street! My friend Bill,who owns Warren Gear and Axle,set mine up about 3 yrs. ago..still in one piece! And I don't BABY my drivetrains! My carrier is an old style from the early 60's with a clutch-plate type set-up. LOVE it! I run a 4:56 Richmond gear with 30" tall slicks..and street tires. My engine makes peak power at 6,000 rpm..through 1/4 traps at 6500-6600rpm..right where I want to be, 10% over peak! I think if you run a 27" tall tire,a 4:30 might be a little steep for the street! I've got a "spare" 489 case 4:10 gear,also set up by Bill,sitting in my pole barn..but I need to hang onto it..JUST IN CASE! If I were you,I'd give Bill a call..just don't mention my name..he might charge ya' double! ...J/K! He's a GREAT guy..and knows what the heck he's doing! My GTX is proof of that! Best of Luck on whatever you decide! Let me know what that is! Thanks! Randy



Wow, it really is a small world. Bill is a friend of mine as well. Went with Bill, Derick (goes by Dericks here)to the St.Ignace meet. Derick drove his Duster and I drove the GTX there, no trailers

Anyway, Bill's a good guy and does good work. He's set up LOTS of rears in his day and will treat you right.
Posted By: Cab_Burge

Re: Will this gear be right for me? - 01/10/11 06:39 PM

The 741 is as strong as the 489 case is The posi are the same so fix it first
Posted By: Labratt

Re: Will this gear be right for me? - 01/10/11 07:27 PM

Marc..that is a coincidence! Bill grew up the next street over from me,in Warren! We use to do a little "street racing" together..back in the early-late 70's! Like I stated,Bill puts rears together to last! In fact,he told me,with the way I drove the X...my 4:56 wouldn't last but 1 or 2 times to the track! Still proving him wrong! His assumption was based on the pinion design,and old-style case! I make a point to tell him the rear end's STILL in one piece,every time I see,or talk to him! Ryan..call him,you won't be sorry!
Posted By: bigsbigelow

Re: Will this gear be right for me? - 01/10/11 07:41 PM

Quote:

Marc..that is a coincidence! Bill grew up the next street over from me,in Warren! We use to do a little "street racing" together..back in the early-late 70's! Like I stated,Bill puts rears together to last! In fact,he told me,with the way I drove the X...my 4:56 wouldn't last but 1 or 2 times to the track! Still proving him wrong! His assumption was based on the pinion design,and old-style case! I make a point to tell him the rear end's STILL in one piece,every time I see,or talk to him! Ryan..call him,you won't be sorry!



I gave him a call on my lunch break. I am very pleased with the quote he gave me. He will be rebuilding my center section soon.
Posted By: Labratt

Re: Will this gear be right for me? - 01/11/11 01:05 AM

Ryan..did ya' make the mistake of mentioning my name??
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