When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
What is all involved in swapping a TKX 5 spd in a 1970 Cutlass S?
It is a bench seat, factory TH350 car. It looks like the transmission, think wide ratio to go with the 3.08 posi going in the Type O. I know pedals, hydraulic clutch, bellhousing, clutch, mount, 31 spline yoke/driveshaft and shifter. Does it need a special crossmember? It also looks like it needs a Dakota adapter for the speedo? I believe my 330 crank is factory set up to take the manual trans pilot bushing. I realize an easy 5K swap and properly built 2004R or 4L80E is 3/4 of that price. Any input or parts missing would be great. The crank is at the machine shop, now is the time to modify it.
I got mine from Silver Sport Transmissions because I liked their installation package - comes with everything you need to install, and I got a hydraulic clutch from them as well. I figure that saved me trying to scrounge up all the random used parts, hoping I got the right ones and they were serviceable, etc. It uses the stock crossmember and comes with a trans mount in the package I bought. I'm not sure if the crossmember needs to be relocated.
Check with the transmission vendor if they have what's needed for the Dakota gauges. I decided to use a GPS speedometer and haven't had to look into that part of things.
Have you calculated your RPMs in the gears at various speeds? I didn't think the 3.08 I had would be well geared and went with 3.73s based on conversations with the tech at Silver Sport. There are various calculators online, but these are the numbers I came up with based on running 255/60R15's which have a 27 inch diameter. (Speed in MPH)
Although not critical (for some), you'll want to find a floor shift collar for your steering column to eliminate the automatic gear selector. If you're sticking with the bench seat you may find getting a good stick shift a bit more challenging.
I was looking at the 3.27, 1.98, 1.34, 1.00 and .72 with the 3.00 reverse. I will check with a calculator but it looks good to me with a 28" tall 275/60R15 tire. Thanks for your input.
I was looking at the 3.27, 1.98, 1.34, 1.00 and .72 with the 3.00 reverse. I will check with a calculator but it looks good to me with a 28" tall 275/60R15 tire. Thanks for your input.
It obviously depends on the type of driving and use the car will see. My best advice is once you've done your research, give them a call and have a chat to see what they have to say.
I'll second Silver Sport Transmission. I got the 6-speed kit from them to convert auto to manual, with the hydraulic clutch. Their customer service really is top notch. It took a long time to get my trans in, as other projects were ongoing, but they were still readily available and helpful well after point of sale.
Be aware, with a 28" tall tire, 3.08s, and a .72 overdrive, you'll really be struggling to get much use out of 5th gear. You'll be turning 2000 RPM at 75 mph. If that works for you, go for it.
It should work, the 10ish to 1 first gear and the .72 OD gear. Yes, the roller cam is below 220 duration, 218/218, 1600 rpm to 2000 rpm should be about perfect cruise rpm. I ran a 214/214 cam with a 25" tall tire, .68 OD and 2.78 gears. 1500 to 1700 rpm highway cruising, OK mileage and power. I also had Mark do up my RPM for SEFI, should help drivability and mileage.
It should work, the 10ish to 1 first gear and the .72 OD gear. Yes, the roller cam is below 220 duration, 218/218, 1600 rpm to 2000 rpm should be about perfect cruise rpm. I ran a 214/214 cam with a 25" tall tire, .68 OD and 2.78 gears. 1500 to 1700 rpm highway cruising, OK mileage and power. I also had Mark do up my RPM for SEFI, should help drivability and mileage.
Sounds like a real nice cruiser. The 6-speed I put in mine is seriously the best thing I've done with it. I have no doubt you'll be happy with the TKX.
February 9th, 2023, 05:25 AM
