[RICK LAKE]

Jon Miller Jon do you want to stay with a speeder car or go auto?? Does your area have all flat ground or are you up in the hills?? Do you want the other half driving the car?? How much money are you looking to spend. Here are the questions you need to answer.
You are running a toploader, what bellhousing is on it? This is because of the safety and a new TKO-600, T-56, or Richmond super street 5 speed will be the choices. 1st gear ratio with 3.31 gears with be in the 2.60-2.80 range. 5th gear will be in the .80's-,70's for OD. .064 to too low for this setup, read threads here about doing this and that the car's are running 70 mph+ in order to not lug the motor and damage the drivetrain. You have a mild motor with a good low end power band. It relys on the torque to move the car along the road NOT HP. HP is at 5000 rpm and 2,200 rpms. Back to question,
New clutch, bellhousing (maybe) drive shaft, possible trans mission mount getting moved. Shifter location may be moved with a TKO trans. What style of shifter is in the car?? You will be doing this with an Automatic trans also.
Brent Bylkins could give you a complete price on this setup, maybe even the drive shaft too to fit the car.
If you are looking for better MPG remove the 2x4's and go with a 600-780 carb in size with a rpm manifold. Yes the 2x4 setup looks nice under the hood but killed mpg when driving. Everytime you touch the gas you have double pumps in the carbs putting fuel into it, That's alot of gas. This is a main part of the reason CS ran single carbs on the cobras and GT-40's at Lemans. He gave up 10-50 HP and also was getting about 4-6 mpg instead of 2-4 racing. The other thing was the KISS method, keep it simple stu--d, and it's true.
I have another thought and may be cheaper, Find another rearend with a 3.07 ratio and install that one. If you go racing or auto cross you can use the higher one for this. Spare parts are nice to have. I have been collection them over the years.
My setup is for the track. I started with a 452 motor and have gone to a 482 stroker motor that is very streetable. Ratio in rearend is 3.31 gears I have 2 trans for racing long and short tracks. Max rpm on the motor is 6,200 rpms. Over 500ft of torque from 2,200 to 5,000 rpms. Hp is only in the low 500 hp. 1 trans is a G-Force 5 spd. 3.25 first gear and 1-1 5th gear. With the bigger motor I don't use first anymore.It's a 5g custom trans. Too much power and quick shifting within a second every time from 1-2. top speed 128mph on chip. 2nd trans is a richmond 6 speed with the same first gear 3.27 and an .87 OD. Top speed about 138mph. This is all fast enough for me. Problem is the tran ratings are 450/450 HP and torque. I am way over this number. Street tires and smooth driving have saved this trans from breakage. I will wind this down pro's and con's
TKO600 They have made great improvements to it, It's a good cheap trans and good bang for the buck. The abuse factor of this trans I question it holding up. If you normal drive and not a big burnup the tires guy, this is a good choice.
T-56. Same as above with extra gear. Alot more work to fit into the cobra. Clutch my become a hydro setup. Double overdrive, is nice but IMO you don't have the power in 6th gears to have the car cruise down the road at speed. You have to remember that you are driving a BRICK through the air and it uses alot of power from the motor the faster you go.
Richmond super street 5 spd with OD, Has the ratings of the TKO 600, 600 hp and Torque. Shifter location within and inch of what you have. same shifter handle my be used if it bolts to a Hurst shifter. This trans is heavy duty and cost is about 1,200 to 1,500 dollars more than TKO. I am getting one for a spare in my car. One less gear to deal with. My Dad always said you get what you pay for. IMO and engineering design this is a better trans for the money. I have had to rebuild t-56 trans from F-body cars, GTO and Vette's. They need about 800-1,000.00 dollars to blueprint them and remove the plastic, weak sliders, better main shafts, and syncro's. There are a couple of companies that do this for you.
I think the easy way would be for you to get another center for the rearend if it's a Jag, from CWI or Michigan drive line. It's a bolt in. Same for a Ford IRS setup. Look for a 3.00 ratio. in the junk yard and have it gone through. The lower ratio will cause a small added wear to the clutch but over time and gas saving with going to a single carb, it's a freebe. If you want to talk more, send a p-m to me. Brent hates when I write a book on here. Just trying to give you the best info I can. The other thing is, been there and done that. Look at some of the older threads about this. It's been covered a couple of times. Rick L. Ps I have 30+ years of turning wrenchs and racing. I make a living working on gm cars.