Hi everyone, I just bought a shell of a 79 corvette and while I'm well away from beginning anything with it, I'd like to nail down my plan for what kind of powertrain I will be putting in it.

The engine im planning on dropping in it is a 454 big block out of my 92 k2500 once the truck rusts apart. The engine is said to be bored .030 over and has a mild cam in it. It is fuel injected but i plan on converting it to a carb when I do the swap.

The corvette was originally an auto but I would like to put a manual in it. I've heard that a 5 or 6 speed would be best for highway driving. That being said, I am completely new and kind of an idiot when it comes to the world of engine swaps but do consider myself to be pretty mechanically inclined. My question to you all is, what transmission do I go with? Ideally I would like to find something out of a salvage yard but don't know what transmissions will fit with the big block and also into the c3. Also, what other components do I need to go along with the swap? Please speak to me like I'm a child when explaining things so I can understand. Thanks!

 

The best trans for your motors torque and ease of a swap is the TKX. you are not going to find one in a junkyard. Anything you pull out of the junk yard will probably require a special bellhousing for the older 5 speeds. You might find a T56 but they are huge and may require a lot of tunnel work.

THe TKX transmission will fit in the tunnel without chopping it up. You would have to make a welded in crossmember removable and would have to change the mouunting pad a little but nothing that a home welder cant handle. If you go with a company that already swaps the shifter you can bolt it right in where the 4 speed shifter would go. You can also shop around for a better price for the tranny and get a shifter seperate made by Modern driveline that bolt on for a C3. https://www.ebay.com/itm/125627358384 This shifter is awesome. Depending on what you do to the engine for power a 1310/1330 slip yoke will handle up to 450 ft/lbs if you go for 500 ft/lbs or more then you will need a 1330 or a 1350. You can buy the split 1350 yokes but they do not make a 1330 split yoke so you would have to make a special driveshaft. Theres talk about it on another thread...I might be able to dig it up. The 1350 requires a minimal kick out in the tunnel for the yoke to fit.

anything you get requires a custom driveshaft which is about $350 for the shaft and $200 for the yoke

 

Welcome to the Corvette Forum Grassfoot43!

I have a 1968 Corvette convertible with a 427 and with the Muncie Four speed and a 3.36 rear end I can cruise all day at below 2000 rpm at close to 70 mph. If I downshift and stomp on it I will be over 100 mph very quickly. My C3 was built during the era of 70 mph with 90 mph passing regularly done. I built the 427 to be a clone of the famous L88 engines and it makes plenty of horsepower to push me right along. With the hp I have the car is capable of dropping into the 10's IF I could get traction and built in a roll cage. Next time I drag race I am taking my hardtop to see if that makes them less nervous, last time they warned me not to break into the 12's or I was done for the day.

As soon as I put D.O.T. slicks on the car things like (half-shaft U-Joints) started to break. As the car was intended to be driven I had no idea that I would have a major traction issue when it rains. The car is unusable with the street radials on wet roads. The only way to buy a "Better" tire would require a wheel size change up to 18-20" rims. I love driving the car on dry roads and have had many miles of smiles cruising along in my C3, just NOT in the rain. If you put 500-600 hp in that car it will likely be like mine where you can't use it anytime due to the possibility of rain. You might live somewhere dry and be okay but in my car you need to pull over for the duration of the rain.

The 1968 Models were built to handle higher horsepower engines like the famous 560 hp engines like the L88 and last for decades. The 1979 Corvette is not going to be anywhere as heavy duty as the earlier C3 BB Corvettes were. Keep your horsepower down and you can make a screaming fast car and still be able to drive it anytime. To keep it Corvette the Muncie works just fine and will save you a bunch of money unless you actually like rowing through the (5th,6th and 7th) gears. Stay away from the 4.11 rear ends and it becomes more live able. With my 427 and the 3.36 rear I outran several Corvettes all equipped with 4.11 rears. My only problem was that I spun my tires past the 1/8th mile mark on the way to the 1/4 mile run. I had two guys make me very generous offers on my car while we were out having fun. There were two others that came up and told me that my 1968 C3 was the wrong color. I LIKE the color and told them to shove off.

The point being is that it is YOUR Corvette to do with as you please. I hope you get all the answers that you seek on this Forum. There is so much experience here on this site willing to help fellow Corvette owners keep their Corvettes on the road where they belong. Again I welcome you to The Corvette Forum!

 

thank you for your advice and and your welcome to the forum!

 

Thanks for your reply. I poked around on tremec's site which led me to a shop's website that is decently close to me that supplies these transmissions. A few questions/ comments about my options. It does give the option for a 1330 slip yoke. Will I need a mid shift kit? Also for the bellhousing, it gives the option for aluminum vs quicktime steel with steel costing more than twice as much as aluminum. Is the steel worth the price difference? Would I be a fool for going for the aluminum?

 

The steel housings are usually rated for racing, draracing and high horsepower. How much horsepower is you max desired?
You need the offset mid shifter to fit the corvette shift consoles. The link on ebay is a perfect choice. Very easy swap.

You need a split yoke. One that you can unbolt the straps to remove the driveshaft from the yoke. You need them at both ends for a c3 corvette, one on the differential which is stock and you have, and the split slip yoke in front. No one makes a spilt 1330 that we have seen.
No you are not a fool for using aluminum bellhousings if you drive like a normal responsible adult...I on the other hand have a steel bellhousing.

And you will need to research how to zero your bellhousing so the transmission is centered on you crankshaft. It's not hard but you will need a few tools like a magnetic base and a dial micrometer

 

I don't really have an idea on how much power I'll want to be making. I don't plan on doing any drag racing. Just looking to build something fun to drive on the road and have the ability to break 'em loose when desired. Although I can definitely feel the power of the big block in my truck, being in a 3/4 ton truck, drives a bit like a dog. I'd imagine when dropped into a vehicle that's a couple thousand lbs lighter, it'll be quick enough for me. As for hp/tq, I don't know how much I'm making now. Whatever I plan on doing to the motor before the swap wouldnt be anything big, so I don't plan on making any substantial gains. I'm attatching a screenshot from the site that gives the option for a 1330 slip yoke

 

I'm assuming you meant 3,000 rpm @ 70 mph. I have the same trans and rear end ratio.

 

Truck/ rv towing cams are real dogs for fun or excitement. They are designed for torque from idle through 4000 rpm usually. If you just do a cam swap to something designed for your heads flow and compression you will be happier. If you go with a bigger cam with somewhere around .550 lift and 230 duration at .050 with a great head like a Brodix Race Right 270 oval port you can be right around 500 hp depending on compression. If you have flat tops you can get to 10:1 pretty easily. Even down to 9:1 you will have a fun engine on 91 octane.

Heads and a good cam will be a great improvement for that motor.
Big blocks with anthing above 450hp are good, 500 hp are really fun, you can spin your tires easily, the torque makes up for the extra weight. You need stiffer front springs and the corvette pulleys for the accessories. I prefer electric fans. On hot days my car stays about 200ºF so it's a happy motor.
Much more hp than that really isn't necessary on the street. I had a 430hp 327 motor that was fun but it didn't have a lot of torque down low like a big block would.

I'm betting that slip yoke is a press fit one that you can't split to get the driveshaft separated from the yoke. You need the split because there's a rear crossmember that traps the driveshaft

 

You need this


versus this

 

I highly recommend you look into Silver Sport Transmission. They supply a complete kit to install the TKX to your BBC. I used SST for my '73 BB and it was very complete! I went with the steel bellhousing to avoid having to use an adaptor, and save my legs. It zeroed-in well within tolerance.

As for a clutch, I went with a McLeod Street Twin with a 24# flywheel, hydraulic T.O. bearing with a 0.700 Wilwood Master. Clutch pedal force is a little more than stock, but very drivable.

I spec'd a 1350 slip yoke connecting to a 2-1/2" diameter steel driveshaft. The rear gears are 3.55's.

As for a street cam, I went with a mild Comp 224/230-110 XFI roller cam. I'm very happy with the top end power along with the easy drivability when I'm cruising between 1200-1500 rpm. This cam also makes 16" of vacuum so the power brakes still work well.