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Discussion Starter #1
Dear god! MORE QUESTIONS! Haha

Anyway, so, I've got the engine build and power adder FINALLY picked out for when I get home (props to Brenspeed in Indiana), which will include a fresh set of detroit rocker cams, and their Roush 560R s/c package, all to be installed by the shop. I'm running an automatic transmission that will eventually be swapped out for a new TCI and ratchet shifter, along with a rotating assembly, also courtesy of Brenspeed once I've got the cash, I'm thinking keeping a 2500 stall or moving up to a 3000rpm stall. Aluminum driveshaft will come with the second round of upgrades which will probably come within a year of me being back home.

Now, to the topic at hand, gears. I'm looking at upgrading from the stock gears to a fresh set of 3.73 gears in the back that will come with the new cams and Roush. Given that this car is going to be a weekend warrior with the ability to go on a cross country cruise, I was wondering what yalls opinion would be on new gears. From what I understand by learning through reading the 3.73's seem like they'd be the best choice over stock without going too far over the edge with 4.10's. But what do you guys think? Should I go with the 3.73's to get that added umph and be able to highway cruise, or should I go straight to the 4.10's?


Edit: I realized that I forgot to mention the expected power results, should it matter in regards to streetability when combined with a different gear ratio. Brenspeed's Roush 560R package and tune typically puts down about 560hp and 458tq, with cams, they say most folks pick up about another 30hp when coupled with the 560R and no notable difference in tq. Not sure if this was an important bit to put in here, but I figured I would.
 

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I have 4.10s and if anything, they make it so much easier to drive with cams. Then again, with a blower grind you probably won't have to worry about losing too much low end. People will say Both, but there are many deciding factors. Use the search function and I'm sure you will come across multiple (heavily debated) threads. Good luck


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If you don't track your car, 3.73's if you plan on any long highway trips, 4.10's will push 3000 rpms on the interstate as the OD on your auto is shorter than the 5sp.
 

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First of all let me give you a couple of suggestions on your build. Don't take this the wrong way as there is really no correct answer, just what I would do in your shoes. Getting the ratchet shifter from TCI is OK because nobody else makes one and it's not really a high performance part. I have one and love it. But that would be the only thing I would buy from them. I have had bad experiences with parts failures from them. Customer service was always good but I've learned to avoid putting their parts on my cars. I would look at Level 10 or PA (Performance Automatics) for your tranny. I have the Level 10 "bulletproof" unit and it is plenty stout. I might wait on swapping out your converter until you actually get on a dyno for a couple of reasons. One, if you're at a 2500 stall with your current power levels it will stall a bit higher with your power gains. I had a 2800-3000 triple disc converter, and now that I am producing a ton more torque it is too loose and stalling at probably around 3400 when I really put my foot in it. It can make for a bit of a jerky ride during light throttle cruising as it locks and unlocks too easily. Also you should base your converter stall speed based on your peak torque. You should look for converter lock up about 500 or so RPM's before your peak torque. This will give you the best performance. You can go a little lower than that if you're worried about streetability. I venture to guess that you will be stalling close to 3000 anyways with the increased power.

As far as gearing, well, that is highly debatable and very subjective. I run 4.10's and love them I think I could have gone with more gear. Yes it might make it a little more difficult to control the torque but that is a driver mod. It always takes time to learn how to apply the power to the ground when you get up into these levels of engine building anyways. I've taken my car on a couple of long trips (well over 1K miles) without any issue. I should also mentio that I run a 29" tall DR on the back which lowers the effective gear ratio a bit. I think I'm probably running closer to a 3.90 effective gear ratio. You will get different opinions on this subject and it all comes down to what you think you can handle.
 

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Discussion Starter #5
I've heard both bad and good in the way of TCI, though you're the first to absolutely striaght up deny their part quality, I'll do some more research in transmissions, however, as the build, s/c, cams and drivetrain will all be courtesy of Brenspeed it all also falls under their spectrum of coverage from what they've been telling me. Naturally, like anyone else, I'm apprehensive when the subject of spending more than a couple grand on my car comes up, simply because I have no desire whatsoever to screw up the process and go with a bad build. But, that's the benefit of working with a speed shop in getting the build figured out I guess. Haha!

Thanks for the insight as it is guys, give the information you provided 07 Boss I'll probably just keep it at about a 2500rpm stall, given that the boys at Brenspeed say that they've had no problems with their own shop cars, personal cars and customer cars who run an automatic with a 2500. I'm thinking I'll also go with the 3.73's for the back, just for those quicker ET's without sacrificing too much in the way of my own comfort of just sitting back during a nice cruise.

Appreciate the info, and as always, thanks for the straight answers!
 

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FBGM
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+1 on what boss said about gearing, I run 3.55s with a manual, I honestly like it.
 

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Open Hood-Insert Money
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Something to consider is the height of your tires. I have a build similar to yours with a TCI trans and shifter, PI 2500 stall converter, Blown, cams, stroker....all very similar.
I have 373 gears and with my 26" tall street tires it is almost too low on the freeway. I tach 3000 RPM at 80 mph.
But at the same time with my 28" tall M/T DR's at the track it's not low enough....so it depends on what is more important to you, drag or freeway driving and how tall your tires are.
 
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