'76 Corvette Engine Rebuild and Transmission Swap Page
November 2001

 

Here is a pic of the original engine in the exact spot the mechanic placed it back in St. Louis in 1975.  The engine is a Chevrolet 350 cubic inch V-8.  The original power rating for this engine was 185 horsepower.   Plenty strong but only a shadow of engines from a decade before or even a decade later.  Still pretty clean after being driven 158,000 miles.  This engine is really worn out.  Still has compression and still runs but it is weak and subject to overheating.  Recently, the timing chain jumped bending seven pushrods and the engine has ran very poorly since then.

 

The engine is out and on its way to the rebuilder... note the damage from persistent exhaust leaks on the passenger side of the engine.

Heat was a number one problem with the old engine...  made driving uncomfortable and even caused the starter solenoid to lock (meaning the car would not start until it cooled).  Ceramic paint is available and I choose to purchase BlackSatin from Tech Line Coatings to beat the heat from the exhaust system.  Tech Line advertises that the heat just does not pass through the coating...  their tests show that ambient room temperatures are detected one inch away from the manifolds with the engine running, impressive considering the exhaust gas inside the pipe is about 800-degrees.  That kind of performance would be great if it's true.  The product requires that you sandblast the part being coated and spray the paint on...  I coated everything hoping to really reduce under-hood temperatures after the rebuild (update - it works).

One problem the Corvette had was a persistent gassy smell... turned out the rubber fuel return line had a small crack near the top of the tank.  Very difficult to reach.  The tank had to come out.  Just as well.  I had wanted to clean the car in that area and as you can see, the tank looks new after cleaning the dirt and gasoline off.  BTW - Can you believe that small of a tank goes in a car with that big of an engine!?!

Now for the fun stuff!!!

I mentioned that the car originally had 185 horsepower...  good, but far from exciting in a car as heavy as the Corvette.  We choose to go back with a 383 cubic inch rebuild.  So why a rebuild and not just purchase a replacement engine?  Primarily because Corvette engines are given a unique engine serial number matching the car its installed in.  For me, this is special.  This Corvette will keep its original engine.  We had the rebuilder install higher compression pistons for a little more oomph and a hot cam that just passes the
California smog check system.  The rebuilder projected 350-390 horsepower at the engine... assuming 25% drive line losses we may be looking at 262-292 compared to the 185 of the stock engine.

Check out that great paint on the 383 rebuild!

We want to "drive" this car and with the small gas tank we needed to really increase the gas mileage to go anywhere.  The solution is to install a modern four-speed automatic overdrive transmission.  Several choices are available but the 200 4R from General Motors is a direct fit replacement.  In addition, of the available choices, the 200 has the most aggressive overdrive for better fuel economy.  We selected a unit from
Bowtie Overdrives.  They build a unit they say will handle 500 horsepower with the proper configuration and that's good enough for me.  You can see the tired old Turbohydromatic 350 transmission off to the right.

Yeah, that’s a
Flex-a-lite electric cooling fan off to the side...  I know they say they’re limited to 220hp but its what I had on the old engine and hopefully it will suffice with the Griffin aluminum radiator.

 

 

Here's the 383 going in...  The fellow in the pic is the daughters boyfrend... Always nice to have a little help when dropping in the engine.

 

So, how does it run?  Really strong!  Push the pedal hard on this car and you'd better be holding on...  It's pretty fast. Goes from 70 to 90 with a flick of the pedal.  Gets a lot better gas mileage too... high mileage so far is 24.6 mpg.  Not bad for a great looking 28-year old sports car.

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