Good day to you all, relatively new here and I'm in the middle of a fairly large complete build I'm at the point where I'm looking to select my gear set for the back and since this is my first F body build I'm a little unsure of what to go with my experience is mostly with building trucks that are very heavy and produce a lot of torque so this is a completely new realm for me. My apologies for the long explanation but I feel the more information the better since one or two changes in one area can completely change the outcome in another.
To start with I have an 86 Trans Am WS6 with the rear disc brakes the current ratio is 3.27.1 when I got the car it had the 5-speed T5 with what ended up being a 350 punched.040 / with an almost zero deck so the compression was up there, and the guy that had it before me had issues with the carb or the factory throttle linkage rather and had the carb set up so the secondaries woodsnap open literally halfway down on the throttle and while starting off pretty mild as soon as that point was met it would be full power and the wheels would just Break Free almost annoyingly so pretty difficult to drive it calmly but as such it gave the illusion the car was much more powerful than it was again it came with almost bald tires and no traction so its capabilities were deceiving. It did however get up to highway speed and when necessary passing other vehicles and jumping up past 110 120 was fairly simple.
now on to the technical the car has been stripped down to just the bare shell it is currently having complete subframe connectors 6 point roll cage tubular K member and Chassis front back and in between I ended up picking up a Richmond 6-speed fully rebuilt and fresh that will pretty much handle whatever is thrown at it and the power plant is an 11.1 compression 383 stroker w/ 2.02 - 1.60 alum heads , I have a few cam sets I'm juggling around with but they are good from 1500,2000 up to 6k. Edlebrock air gap intake and 650-700cfm carb, long tube headers with 3" duals out to the back. Precision balanced Steel drive shaft is also being employed along with Transmission crossmember with integrated tubular adjustable torque arm by spohn connects to a Moser 8.8 rear Outback with Umi lower control arms panhard bar and the suspension is QA1 coilovers at all four corners. The wheels are 16 x 8 GTA Wheels and I'm a little undecided on the tires as of yet I'm still researching what would make for the best combination of traction and handling.

As far as the overall weight of the car goes I'm not a hundred percent on the overall savings with all the tubular chassis replacements though I will be using a fiberglass hood and I do have an original 88 GTA notchback hatch that is supposed to be lighter than the large glass hatch though when trying to move it around it doesn't appear that is the case but all the HVAC is removed, all the factory power steering and linkage is gone in favor of a manual Pinto rack that came with the K member and aside from the rear seats being deleted the whole interior for the most part will be there and the factory fuel tank is being replaced with a 15 gallon fuel cell.

the Richmond 6-speed double overdrive transmission gear set are as follows 1st 3.27 , 2nd 2.13 , 3rd 1.57 , 4rd 1.23 , 5th 1.00 , and 6th 0.81.
I'm also still looking at clutches as well so when I have a better idea of what I'm looking at I will pull the trigger on that as well. Any suggestions or personal preferences would be seriously taken into advisement.

ideally I want ridiculous off the line launching and acceleration along with really good highway speed pulling as well and I'm curious if I should stick with something along the neighborhood of the 3.27 gear set that I've been rolling with so far or if I should lean either higher or lower being that it's a 6-speed overdrive that changes things but I simply don't have the experience and I'd like to have some input if possible and it would be much greatly appreciated. Thank you in advance.

 

Those look like REALLY HORRIBLE transmission ratios to me. Not so much the ratios themselves, as the step between them. 2nd - 6th look OK, although 3 4 5 & 6 are kinda close; 2 - 3 is kinda normal, but 1 -2 is YYYYYUUUUUUUUUUUUJJJJJJJJJJE. Makes a 700-R4 1-2 shift look close-ratio. To the point in fact, that it's useless. If you shifted when 1st was wound up to 6000, 2nd would be at about 3900. Just altogether too much RPM drop to be useful. 2-3 by comparison will recover to 4700 RPM from a 6000 RPM shift, 3-4 also to about 4700, 4-5 to about 4900, and 5-6 also to about 4900. Not sure what they're thinking with that, but w/e, numbers don't lie.

Rule of thumb is, for a typical street-strip car, you want the final drive ratio in 1st gear - transmission ratio times rear ratio - to be somewhere near about 10:1, no higher than 11:1 and no lower than 9:1. With a 3.27 1st, that means your rear would need to be about a 2.73 or 2.77. But with a gear like that, everything else except 1st, would be absolutely awful. Granted, that's just a rule of thumb, and not anything absolute or definitive; doesn't take tire size into account for example; but it gives you a good starting-out reference point. To put it in perspective, your T-5 (2.95 1st) and 3.27 in the rear, gives a final drive ratio of 9.6. I have no doubt whatsoever that a decent running 350 will absolutely blow the tires up in smoke (given that a 305 will) with that ratio, and a 383 will be just that much worse. I know in my car, when I had a 400 in it, I couldn't use more than about half throttle in 1st AT ALL (same T-5 as yours, 3.73 in the rear). If you think your 1st gear is useless now, ... imagine 15% more torque AT LEAST, and a final drive ratio near the upper limit of 11, just with your 3.27s. Then with for example 3.73 and your 3.27, your final drive ratio in 1st would be about 12.2. No chance of ever hooking it up. You'd have one of those deals where the instant you stand on it in 1st you'll have to shift immediately, then when you grab 2nd, it'll bog down worse than your current setup does.

If it was me I'd probably look at 4.56 or so, and not use 1st at all ever for anything. That would put you at about 2750 RPM at 60 mph.

 

indeed you are correct the thought never occurred to me since I'm always used to Muncie and Saginaw Transmissions with the ridiculously low granny first year it didn't seem strange to me with driving my old square body trucks but I did just look it up real quick and yes those Transmissions were made specifically like that because apparently back in the day when they were in common use most muscle cars had 411 and 456 gear sets where they didn't really use the first gear that much and with the double overdrive 6-speed there was no issues but then they changed everything around after the gas crunch when most gear sets went to 308 as a commonplace. So long story short I should look at this transmission as more of a 5-speed instead of a 6-speed and gear accordingly as to essentially delete the use of first gear. That being the case what would I be looking at then where I could still take the car up to say 140 if I wanted to if that is even a possibility and while still having the crazy off the line acceleration? Are 411 just not enough to cut it or would going up towards 456 be more to the point what I'm trying to achieve?

 

That only has one overdrive gear. Double overdrive is suppose to be two gears less than a 1:1 ratio like a factory T56

the gear ratios arent super terrible, not all that much different than a T56 as far as rpm drop between shifts. 1-2 drops more than i’d like to see for sure but is what it is

most street guys like 3.73-4.11 with T56 cars and motors that pull to 6500. Obv powerband and shift point will determine what ratio you need. Higher the rpm peak the more gear you can run, more power you make sometimes less is better

 

that's a little bit of what my line of thought was originally when I was looking at this as I said previously I've always had trucks not really something I made a conscious decision of they just always fell in my lap and I just made them work and most of the time they came with 4 speed trannies but realistically they were really a 3-speed with a almost unusable 1st gear unless I was using it to pull a trailer or I'm hauling a heavy load or something the 79 K20 I had I ended up lifting a bit and in throwing larger 36 inch tires over the factory 28 inch tires that it originally had I was able to use that first gear somewhat regularly. Obviously this is a different scenario but that's why I was wondering if there's some tweaking that can be done somewhere where I could still use all the gears and not be completely screwed With performance in one area or not I tend to be greedy so I kind of want it all if possible. Other option I considered if if there's a possibility to have the transmission pulled apart and just swap out that first gear if there are options available for sure if it's pretty set with that particular set up which it seems like it might be but couldn't hurt to ask

 

I mean it depends what you need the car to do but even a 3.06 first gear found in 700r4 automatics with a 3.42 gear rear, makes first a very quick gear lol. Even on my 7000 rpm 383 i had, it still was kinda useless. At the track it worked decent enough for fairly good 60 foots.

3.27 first in yours with higher number Rear gears than 3.42 would be a quick shift job when racing it. But guys do it all day long with t56 and 4.11’s. Not so bad if just soft driving.

 

Well it's certainly good information I've gotten so far and to add to it I was just perusing around online and looking around and I discovered on the Richmond gear website it turns out that that exact 6-speed transmission and several of their other model Transmissions all the gears have optional ratio Samson you can switch out and mix and match to a degree and in this instance I can simply just switch out the first year for a more favorable ratio it turns out so that makes things a lot last troublesome so with that being the case changing out first gear to a more favorable ratio isn't so much of an issue now so I guess considering this what would be the ideal rear end ratio? Honestly I kind of feel like an idiot now I usually don't like to look around for information online that much cuz it's really hard to find accurate information and I find that nine times out of 10 asking those with actual real world experience Trump fundamental or educational resources any day.
to reiterate fast acceleration and launches while still being able to look and pick out any Highway Lane position and just go for it at will

 

Literally my lack of experience is starting to show I just went back and contacted Richmond transmission with the serial number and everything off the transmission it turns out the information I got from the original owner of this transmission was way off.
this is a DD Richmond 6-speed the gear ratios are as follows first gear 3.01, second gear 1.88, 3rd gear 1.36, 4th gear 1.19, 5th gear 1.1, 6 Speed 0.62

it was described to me from the nice gentleman at Richmond gear that these Transmissions were specifically designed to have the larger percentage drop be between the first and second gear because first gear was mostly used to get the old muscle cars and trucks of back in the day that weighed a metric shittens going off the line and once they were up to speed the RPM and torque numbers right in the middle of the RPM band around 3,000 RPM would keep it in the sweet spot to take it the rest of the way which is what we were talking about what that first assumed gear ratio I thought I had but at any rate from what I hear from him with the stock diameter of that 245 50 R16 tires that being 25.65 in in diameter the gear sets in that transmission with the 383 stroker with 410 horsepower 420 ft lb of torque with a top RPM of 6500 to 7000 355 wood put me right in that sweet spot range of 10 to 10 and 1/2 final drive ratio. Now he did say it varies on personal preference where it can go and he there Direction up to 373 or even down to 308 so my next question would be what all have you used that gets you the most amount of performance benefits? And again I realize how dumb I must sound with all this but I got to start somewhere with building my knowledge and I know full well I may not go about learning what I need to do in the best way but the important thing is that it's not a mistake if you learn from it

 

Usually start with the ratio that puts you thru the traps in 4th gear at just past peak hp rpm. If 1/4 mile racing.

but usually 4th is the 1:1 ratio gear. Yours is 1.19:1. So probably use a touch less gear than a t56 car.

idk why 5th would be 1.1:1 when 4th is 1.19. Thats kinda a pointless shift.

my guess a 3400 lb thirdgen with 410 hp would trap 112-114 mph at most in good air. So find out what gear gives you 114 mph by 6000-6500 rpm or so and thats a start

 

good to know. There is a calculator on richmond gear that might help figure that. I'll see what I find

 

Maybe I missed something...
But It sounds like the OP has a Borg Warner 9-Bolt differential, and there are not too many choices for Gear-Sets.

The ONLY new Gear-Set that I have been able to purchase for the last 10 years is the 3.70:1 set.

 

it did have the stock BorgWarner but I have a Moser 8.8 from Hawks and I'm just trying to narrow down a gear set since I've never ripped around in a car like this before, mostly trucks trying to figure out what the best well-rounded set would be, having heard the various opinions and input, I've been kind of thinking 355 honestly if I stick with the stock size tires but if I need larger sticky tires might need a jump it up to 373

 

I recommended the 3.01 / 0.63 Richmond many years ago to a friend. He ran it with 3.73 rear, 26" tires, and I got to drive it a little bit at a car show. Scaring others in the car by ripping off shifts w/ the Long shifter is good times.

I vote you try it with the 3.27 rear. Then, when you know what you like about it, and what you'd change, change to what you actually like. It should be very drivable, with your preferences and the torque curve of the motor making the difference. I wouldn't go past 3.73, assuming a change is felt to be "needed."

 

sounds like a good way to go, do you recall the top speed he was able to get that car up to with the Richmond with the 0.63?

 

Come on, grow up.
Top speed doesn't matter for a street car.

Also, not all transmissions can handle high torque in overdrive gears. Sometimes the 1:1 gear is the last usable top gear in racing. That's how it is with my T56 6-speed trans.

 

just a question, Does it really matter what the top end is that I'd probly never take it up to? Probably not, closest track to me is literally 5 minutes away and it's 1/8 mile track. Nearest quarter mile track is it least 3 or 4 hours away from me, not a lot of opportunities to get up past a hundred around here unless it's on the highways around here, Still curious . Cuz I never got to try it on anything besides the mild 350 and t5 with bald tires and an assload of wheel spin. Beyond that it's been a handful of old Chevy 4 by 4 square body trucks with Granny gear 4 speeds, an 8-speed Peterbilt 587 and a 10-speed Kenworth t700 and a few garbage manual front wheel drive Hondas, one of which was a 4 door , not really the best examples for comparison on what I can expect from this build I am undertaking

 

https://ls1tech.com/forums/western-m...e-tickets.html

 

I would look at choosing a gear based on how you want 1st gear to behave. That's how drag races are won and lost. Everything after that kind of doesn't matter a whole lot unless it conflicts with your ability to cruise at a decent rpm on the freeway or the engine tops out before end of 1/4 mile. Usually people don't have to worry about running out of gear in the 1/4 mile. Orr89RocZ does because he's so darn fast, but that's not normal.

Don't fear the gear with a manual trans. Clutch lockup happens sooner and car is easier to drive. It can actually be easier to pedal the throttle for traction with a numerically higher gear because the tires won't spin so fast as the rpm's rise like it will with a lower gear. And there's always the option to get stickier tires....

Highway rolls are different than a standing stop. The car is already rolling and can drop into power band immediately with a gear shift. All you need to do is drop into a gear that puts you at peak torque and push the throttle to the floor. I do a lot of driving at 55 mph and 3.73 gear puts me in that sweet spot for my car and my engine's power band. You'll just need to do some math and figure out how that works out with your engine and trans ratios.

 

I always calculate top MPH to choose my gears.

For example at 3100lbs 500rwhp I need 3.5:1 rear gear for 1:1 final transmission gear to put my 27.4" tall tire at 140mph before 6500rpm roughly which is about as high as I like to spin a stock 5.3L truck engine from 2002 with 220,000 miles. Even though its my daily driver I still take it out and consistent trap 125mph using the same street tires as always with the power turned down a bit.

 

Get a manual trans and see how you like that 3.50 gear. You won't. Auto & Manual is like Apples & Oranges

 

I don't know.

0.63 and 3.73 is a decent setup to go up to 140mph if your driveline is balanced well.

knit 1 purl 2, brah. Boys are gonna have their fun, don't rock back on the dog's tail.

 

I wouldn't be so sure about that.....

The last useful gear in that trans is 5th (which according to the OP is nearly the same as 4th for some bizarre reason). Shifting into 6th dumps the engine speed almost 50%, plus the overdrive ratio kills off a ton of torque too. It'll literally be the end of the show. If the car can continue to accelerate then it'll be VERY SLOW at best. That 6th gear is for cruising only.

That trans has awful gear ratios. Like bad enough to become really annoying in real life and there's going to be lots of regret and buyer's remorse. Every gear spread is so bizarre that it's hard to believe that it is really true. Personally, I'd want to confirm what ratios the trans really has by turning the input shaft about 10 times while counting turns of the output shaft, and do it for each gear. If it ends up being true, then I'd sell the trans in a heartbeat and get a T56 or something else with better gear ratios.

 

that transmission was confirmed by serial number and model with a Richmond gear rep that I contacted a few days ago and with all the input I've gotten in reference to the ratios and the purpose for them I picked his brain a bit on the phone for a good 15-20 minutes asking every thing I could think of about this trans and why they're set up the way they are and as it was described to me they were specifically designed that way I guess between the first one I thought I had with the ridiculous 1st to 2nd jump and then receiving the correct information on the updated ratios apparently that's there tried-and-true provin line up gear pattern in this particular gearbox and he was very adamant to say that they work very well in muscle cars , Corvettes and they have a direct bolt in model that swaps directly with the F body T5 apparently the performance is there. It may have been a case where he was hyping up their product a bit but it sounded pretty convincing the way he was describing it I've never used one so this will be a first time for me to try one out and and actually see what it can do , I've got it now and if there is a plus side to anything apparently they're pretty Bulletproof if there's any good takeaway from this. At this point I've heard good and bad about what this setup will produce I guess I will make a selection on my rear end ratio given the advice I've gotten here which again much appreciated, and a lot of the negative will be taken as well for consideration I got to start from somewhere to gain experience on either making it a success or making a few mistakes and correcting them as they present themselves. Any screw-ups are mine and mine alone and I will own them I have no disillusions about that . I'll still drive the **** out of it either way.
Now ,Considering the lead time for shipments of incoming parts, and the work I myself am performing on every aspect of this aside from paint and actual engine machine shop work, the timeline when I'm hoping to have this fully assembled, running, and on the road should be beginning to the middle of August for those of you who are curious I will author of a build post which I will start in a few weeks here once I've gotten a large chunk of the assembly done . Currently I'm taking care of a few section of the floors and a few other random spots that the previous owners butchered on it with their misguided attempts at whatever it was they were trying to do. Strange off the wall type things like prying Parts out and damaging the sheet metal instead of just pushing in release Clips or removing the screws and bolts, like really really bad stuff. Also I will have a complete list of every part that is going into this along with any minor option variances available and a bit of some photo documentation for those interested in observing. I live on the outskirts of Buffalo New York in a town called Lancaster pretty much one of the biggest snow capitals of the country so we really only get about a good 4 to Maybe 6 months of good driving weather a year so we tend to value our time with our nice cars when we can. It's mostly trucks SUVs and crossovers for the most part otherwise year round . Thanks again

 

This document has the gear ratio options for Richmond 6-speed.
https://www.richmondgear.com/wp-cont...g_Section2.pdf

Now look at this chart. I've taken a dyno curve of a random Chevy SBC that I found online and married it to a T56 trans and your Richmond trans for comparison (using the numbers you shared earlier). Now do you see how bizarre your transmission is?

1-2 shift is large.
2-3 shift is okay.
3-4 shift is too tight and almost pointless.
4-5 shift is extremely tight and totally pointless.
5-6 shift is waaaaaaay too large.

Don't get too excited about the high Hp from 3rd to 5th gear. What's actually happening is the driver is off/on the throttle 3 times from 90-110 mph and that's slowing down the car big time. And the super tight ratios is dead-ending the car's ability to go faster.

And those tight gear shifts back-to-back-to-back are going to annoy the heck out of you cruising at lower rpm's on the street. And you won't be able to just skip a gear and go into 6th because it's too much of a drop and engine will lug. Your trans will turn a daily driver into a nightmare.

 

I think you made a typo with 5th gear where it's actually 1.0 ratio, which make things look a little better. You'll probably end up skipping 4th during normal driving and going to 5th. And 6th will be unusable until you're on high-speed freeways, so you'll basically not ever have an overdrive in town and on 55 mph backroads.

Plotting rpm vs. mph for every gear will give you a better look at cruising manners. I'll let you invest the time to do that for yourself.

 

thanks for that

 

So did you buy this transmission used or new?

 

brand spanking new I got it at a restoration shop for Camaros Firebirds and other muscle cars called Camaro Specialties it's in East Aurora New York it's literally a treasure Trove but apparently some old timer was having a car built and ordered parts had brought everything there and then the man ended up having a heart attack a few months later and died and all these parts literally just sat there until they were okay to start selling them off and his transmission was one of them. Apparently he was building a 69 GTO. But then after looking closely at the Richmond pages with all the different transmissions in the gear ratios that came with the one I have appears to be even made for these applications so if the ratios are so funky then why do they swear by them? I mean the tried-and-true race numbers don't lie but again why are there conflicting side saying that their way is the best?
I mean with what I've done with the trucks I've built some of these ratios look like something that would be in a ridiculously heavy 4 by 4 like a 1 ton or something but if they say they're specifically for muscle cars even s bodies then what gives