Intake Manifold Installation

Progress is moving along pretty well at this point. It’s just a matter of getting parts bolted on at this point!

This week I decided to start with the installation of the new water pump. To start I applied a little bit of black RTV to the block and pressed the new pump gaskets in place. (FYI – If you’re wondering, the intake isn’t installed at this point, it’s just placed there to prevent stuff from getting in the motor).

After applying a bit of RTV to the water pump flanges I installed the water pump and bolts and torqued them to specs. For those curious I decided to go with a new high flow aluminum water pump. These big blocks produce a lot of heat so a little extra cooling capacity certainly won’t hurt things.

While I was at it I took the time to install my new fuel pump – a Holley high volume pump (part number 12-454-13). Considering this pump is rated at 130 g.p.h. it should have no problem keeping the carburetor adequately fed. As part of the install I also replaced the old fuel pump pushrod and used a new fuel pump gasket.

Next onto the headers… For what it’s worth I really wanted to go with side pipes on my car but I had a lot of concerns about how loud they are. In the end I decided to play it safe so I’ll be going with a dual exhaust setup. Besides, in the end this option will cost about half as much as a good set of side pipes! As it turns out there is a pretty limited number of options available for big block Corvette headers. In the end I decided to go with Headman Full-Tube Headers with 2″ primaries. I ordered painted headers, rather than ceramic coated, for a few reasons. First, I want to be sure they fit properly with the motor installed. It would be a waste to buy the ceramic coated headers and end up damaging the coating while “tweaking” them so they fit right. Also, I wanted to get the motor tuned properly before putting ceramic headers on the motor. If the motor happens to be running lean during break-in and tuning the heat from the headers could scorch and discolor the ceramic coating.

Once everything is in place and the motor is tuned properly I plan to have the headers ceramic coated by Jet-Hot. Their sterling coating works great and looks almost like chrome. It’s real nice looking stuff!

So, onto the intake. In order to prevent vacuum leaks getting a good seal on the intake gaskets is very important. To ensure a good seal, and to help keep the intake gaskets in place while positioning the intake, I used Edelbrock’s Gasgacinch on the cylinder head surface and on the cylinder head side of the intake gasket. This stuff works great at holding the gasket in place during installation. From what I can tell it’s contact cement with a fancy name.

After applying a thin layer of Gasgacinch to the cylinder heads I also applied a bit to the back side of the intake gasket.

 

Once the two parts had dried for about 5 minutes I carefully placed the gasket in position and pressed the parts together by hand. Next I slid a large socket across the gasket surface, pressing down firmly, to ensure a good even seal. I removed the excess Gasgacinch with a piece of paper towel and a bit of lacquer thinner.

For my installation the cork end gaskets that came with the intake gasket kit need to be left out. In place of the cork gaskets a 1/4″ bead of Black RTV is used to seal the ends of the intake. I also applied black RTV around all of the intake and exhaust ports, as well as around the water passages and bolt holes, in order to ensure a good seal between the intake and gasket.

After carefully lowering the intake in place I installed the intake bolts and torqued them to specs using the torque sequence shown below. I should mention that I decided to go with Edelbrock’s Performer RPM intake. This intake will work great for my application since it’s designed to produce maximum power between 1,500 and 6,000 RPM. Luckily, I have an L-88 style high-rise hood since this intake is much to tall to fit under the stock Corvette hood.

Here’s the torque sequence for the intake manifold. Edelbrock designed this intake to fit both early and late model motors and, as a result, bolts #13, 14, 15 and 16 weren’t used on my motor (there are no holes in the cylinder heads for these bolts). To avoid having empty holes in the intake I simply cut four of the intake bolts short and stuck them into the empty holes along with a bit of RTV to hold them in place.

As it turns out I had to go through most of the intake installation procedure twice. I first started out with the Fel-Pro 1275 gaskets recommended by Edelbrock which are 1/16″ thick gaskets. However, when I went to install the intake manifold the bottom of the intake bottomed out where the 1/4″ bead of RTV was applied. This prevented the intake flanges from making contact with the intake gaskets – it was to the point that the car probably would not have run had I left it as-is. If I had to guess I’d say this happened because the deck was blocked during the machining process which basically lowers the cylinder heads. To address this issue I ended up using 1/8″ thick Fel-Pro 1275-5 gaskets. Luckily for me the second time was a charm. With the intake in place I was able to install the new carburetor. I decided on a Speed Demon 850 CFM carb with mechanical secondaries and annular boosters. I chose annular boosters because they do a great job of atomizing fuel at low RPM’s resulting in great low-end power. They will also help to compensate for the fact that this carb is just a tad oversized for this engine and car set-up.

After installing the electric choke kit and fuel line kit I put the new carb gasket in place and bolted carb to the intake.

  

Well, here’s where it stands! It’s getting closer and closer every day! It won’t be long before it’s time to fire this baby up!

  

That’s it for this update! It’s hard to believe that in the past few weeks I broke the 400 hour mark on this project. Originally I figured this project would take me around 600 hours. On second thought, it may be more like 700 hundred hours. Yikes!