|
|
|
|
Hotrodders.com Project of the Week
To see our Project of the Week archives, click here.
Part 7: Induction System
In my dreams my car was to have a blower. In reality, I couldn't afford one so I settled for a carburetor and the fresh air scoop. In the first article, I showed the sheet steel tunnel ram that I ran for a couple of years with a 50's Rochester 4-jet. In about 1970, while I was still in college, I bought a Holley 3-bbl, shown in the picture below, and ran it a while.
(Click photo to enlarge)
It was WAY too big and with the bad low speed performance from the tunnel ram, I could barely idle. The picture below shows the aluminum inserts I machined up to reduce the 780-sized primaries to about 600-size.
(Click photo to enlarge)
This helped. However, I knew the tunnel ram had to go. Unfortunately, no one ever made an aftermarket aluminum 4-bbl manifold for the early hemi! They made blower manifolds of course, injectors, 4-2's and 2-4's, etc., (shown in the pictures below) but no single 4. Of course Hot Heads has recently made a single 4 manifold, but about 15 years too late for me!
(Click photos to enlarge)
I had an added problem; the 331 was unique in the hemi family in that it had the thermostat housing in the intake manifold. The others all had x-over pipes that bolted to holes in the head for the thermostat. If I could have found a manifold like in the photo below, I would be in good shape.
(Click photo to enlarge)
Unfortunately, Chrysler made precious few of these; the one in the picture above is the only one I have ever seen. I took this picture from an eBay auction and it sold for $700 or $800. 99% of the 331's came with 2-bbl cast iron manifolds. The picture below shows my attempt to convert the old tunnel ram manifold to a single 4-bbl.
(Click photo to enlarge)
I even went so far as to have it powder coated. I tossed it 'cause I didn't like how it came out. I finally decided to try to use a 354 intake 4-bbl manifold (stock one is shown in the picture below).
(Click photo to enlarge)
The first thing I needed to do was adapt my big bore Holley carb. I got a carb adaptor from Speedway Motors and bolted it to the manifold. Then, using a hole saw that fit the adaptor (shown in the picture below), I opened the bores in the manifold on my drill press.
(Click photo to enlarge)
A little cleanup with a burr and it came out great, as shown in the pictures below.
(Click photos to enlarge)
Next I had to figure out a way to put a thermostat in the manifold. The picture below shows where I drilled holes in the manifold and brazed in a couple of 1 1/4" water pipe stubs. I ground off all the un-needed bosses and smoothed the surface and had it powder coated. Works great!
(Click photo to enlarge)
The picture below is a cartoon of the right and wrong way to set up the throttle return spring on a carb. The goal is to have the spring put force on the throttle actuating system anywhere but on the carb throttle shaft. If the spring puts a load on that shaft, it wears it out very quickly because it has no bearings or lubrication. Air leaks quickly occur.
(Click photo to enlarge)
The picture below shows how I did mine. Note the spring puts all of its stress on the ball bearing crank which is designed to take the abuse. My throttle shaft only sees a light push and pull.
(Click photo to enlarge)
The picture below shows a little micro switch that is set to close when the vacuum secondary pot begins to open the secondaries. It lights an amber grain-of-wheat yellow LED on my dash and is very handy in tuning the secondaries on the carb.
(Click photo to enlarge)
The picture below shows the Edelbrock O2 monitor I use to tune all my cars. The sensor is temporarily screwed into the collar that is brazed onto the exhaust just past the header. The wires on the readout head are long enough to reach inside the passenger compartment so I can drive the car around under various conditions and obtain readings on the air/fuel ratio. I use this info to jet and power valve the carb. Once tuned, I remove the unit and plug the collar with a bolt.
(Click photo to enlarge)
Click here for Part 8: Miscellaneous Interior Items
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
Record your hotrodding project in our Hotrodders Project Journals. Add photos and information as your project progresses. Easy to use, and completely free. Click here to check it out.
| Hotrodders© 1999 - 2012 All Rights Reserved |
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)