Rebuilding and Upgrading the Corvette L-48 Engine | Part 5


Finally! After a few weeks of preparation and one delay (I was out of town for one week), my 1976 Corvette Stingray is back at Sunrise Automotive and the freshly rebuilt V8 is back home in the engine bay.

I am keeping my fingers crossed that I connected everything correctly when I detailed the wiring harness and that my steering column rebuild is up to the task.

Especially the ignition switch harmonica connector swap I was forced to make so everything would plug properly with the factory wiring harness.

I do know that the turn signal canceling cam is not operating as I think it should, and that may be related to the steering shaft alignment at the rag joint, so I will have to address that issue when the car is back home. It is more of a PITA than anything else, but we'll see what needs to be done to correct any issues.


I stopped by the shop today to see what kind of progress they've made, and things are looking really good. Billy, one of the mechanics, was wrenching away at it and had the tranny back in along with the exhaust and much more.

We did see some seepage from the power steering so they'll keep an eye on it. If it has to be replaced I guess that's that, but hope it's just a matter of tightening one of the hoses. We'll see.

I am very pleased with my decision to use as much new Grade 8 hardware as possible since now was the time to do this. An added expense that makes a huge difference. Also, glad Billy was able to remove the old rusty exhaust studs and install the new ones I bought.


My truck's air conditioning was showing signs of low Freon gas, so I stopped by the shop this afternoon and Mark hooked up the machine to see what the problem was.

While that was taking place, I helped Billy for a little while since he was ready to install the carb and a few other pieces, which we did. He then topped off the fluids and checked things over.

My suspicion about the power steering pump being shot was, unfortunately, correct. So they will order a new replacement tomorrow and take care of it.

After all the fluids were topped off, I did the honors and fired up the engine for the first time after the rebuild! When it roared to life, it was an amazing feeling and it immediately settled into a smooth idle.

But since by then it was closing time, we decided to quit on that high note and the guys will be back at it tomorrow morning.

Happy to report that my steering column and ignition switch worked flawlessly. Well, except for the horn contact which I will need to address since the horn is not working correctly. That's a tiny detail, though, and I will fix that problem as soon as the car is back in my garage,


Another milestone was achieved today. The 20-minute stationary break-in period was conducted without any problems.

First, we adjusted the idle to 1500 RPM, and after a few minutes running it increased to about 2100 RPM. Also, a couple of the lifters got a little noisy for a while, but the motor quieted down after about 15 minutes.

At that point, Mark dropped the RPM to around 800 and we allowed it to run for another 10 minutes or so.

The water temperature gauge indicated a steady 210° once the motor got to operating temp, which is great considering this was a stationary test. I am guesstimating water temps should be in the 200° range under driving conditions.

Mark did spot a tiny coolant leak from one of the water pump bolts, but they will address that issue after the engine has cooled down. And the new power-steering pump is in, so that issue has been resolved as well.


I stopped by Sunrise Automotive again after lunch as they were reinstalling the hood, which took a few tweaks so it would line up correctly. When that was done, Mark and Billy made sure everything was tight under the hood as well as under the car.

Even though they recharged the a/c system which, after they tightened a few fittings that were loose and ensured it was holding pressure, the system would not come on at all. It could be something as simple as a blown fuse or it could be something more serious, but that's a project for some other time.

After everything looked okay, Billy and I went for a short test drive after Mark gave me precise instructions not to go over 3000 rpm and basically baby the motor, something I have to do for the first 1k miles.

I only drove it for about five miles since it was a shakedown test drive to make sure everything looked okay. The motor seems to run a bit hotter than before since the temperature stays at around 210° versus the previous 190° before the rebuild. Mark attributes that to the fact that everything is tight and new, so temp may come down after a while. Not a big deal either way, but it was something I noticed.

Oil pressure also reads a lot higher, as well as steadier, than before. And that's a good thing.

After the first test drive, I took Mark for one and he said that he felt my car was performing like a new Corvette.

The tranny shifts beautifully although we were having a little difficulty getting it to shift into reverse at first. The guys felt the fresh gear oil needed to circulate a bit since the transmission shop had it completely apart to inspect it and install all new seals.

After a while, it seemed to be going into reverse a lot easier, but they told me to just drive the car for a while and, if the issue persists, they would adjust it a bit.

So I have my car back in my garage with a freshly rebuilt engine and much more. I have to say that it felt strange not to have the gasoline and burnt oil stench I was accustomed to every time I closed the garage door. And a quick check under the car only revealed a clean floor instead of the typical fluid spots.

Needless to say, I gave the car a quick detail and plan to do more of that over the weekend.

The whole process took roughly two months, from start to finish, which is not bad in my opinion considering that I was out of town for a week toward the end of the process, and taking into account weekends and Labor Day.

I will be very diligent during the 1000-mile break-in process and then will have the car serviced to make sure everything looks good. At that point, I will also have it dynoed to see what the real numbers are, and plan to have a complete report along with detailed engine specs.

In the meantime, stay tuned for the next update.

Thanks for following my '76 Vette Blog!

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