What do I do to convert a 1965 turbo to dual carb

[64intn]

I have a 1964 Corvair with a 1965 turbo installed. I want to convert it to either a dual or quad carb setup. Can anyone tell me exactly what I need to do to make this setup work? I think I need to change distributer, timing, etc. Thanks in advance. Also, I am interested in a four carb setup. Jim

[Scott V]

do you have the pm's i sent last month? that gave you all the info. ill send them again if you dont have them now.

-Scott V.

[bbodie52]

I have a 1964 Corvair with a 1965 turbo installed. I want to convert it to either a dual or quad carb setup...

Are you saying that you have a complete 1965 turbocharged engine installed? (Engine serial number with suffix code "RL"). Or do you have a 1964 turbocharged engine with a 1965 turbocharger installed? (Engine serial number with suffix code "YR"). There is a big difference in the "short block" between a 1964 bottom end and a 1965 bottom end (cylinders on down) and compatibility with 1965 and later 110hp or 4-carb 140hp cylinder heads.

• The 1964 164CI 110hp dual carburetor engines and 150hp turbocharged engines use the same camshaft (340° duration). This same camshaft grind continued to be used in the 110hp and 140hp 4x1 engines produced in 1965 and later Corvairs.
• The 1965-66 164CI 110hp dual carburetor and the 140hp 4x1 carburetor engine uses the same camshaft (340° duration), but the 180hp turbocharged engine uses a different camshaft (372° duration intake/360° duration exhaust) that is unique to the 180hp engine. So the camshaft found in the 180hp engine was not a match for the 2-carburetor 110hp heads, or the 140hp 4x1 carburetor heads.
• The 1964 turbo engine bottom end (suffix code "YR") would have an appropriate crankshaft, connecting rods, pistons, and camshaft to be matched and fitted with 110hp or 140hp cylinder heads. HOWEVER, the 1964 cylinder barrel outside diameter of 3¾" is only a match for 1964 110hp cylinder heads. The cylinder barrels used with 1965 and later cylinder heads have an outside diameter of 3-15/16", so 1965 and later 110hp and 140hp cylinder heads would require a change of the cylinder barrels on a 1964 short block to properly mate with the combustion chamber opening in 1965 and later cylinder heads.
• The 180hp turbo cylinder heads would not be a simple match for mounting dual carburetors, because of the wrong camshaft and low compression ratio. The heads also lack the needed automatic choke mechanism and ports for the vacuum balance tube.

So if you have a complete 1965 180hp turbocharged engine, you could bolt on a set of 1965 or later two-carb 110hp heads, or a set of 140hp 4x1 heads. But the camshaft in that 180hp short block would be a mismatch.

If you have a 150hp short block, the bottom end, including the camshaft, would be a match for the 1965 and later 110hp or 140hp cylinder heads, but the cylinder barrels would have the incorrect outside diameter for the 1965 and later heads.

Of course the carburetors, air cleaner assembly, PCV tubing, vacuum balance tube, fuel lines, exhaust system, distributor and throttle linkage would have to be matched to the new heads. The engine upper sheet metal would also change because of the different exhaust system routing and the openings for the automatic choke rods.

Another possible approach: If you have a complete, serviceable (very rare) 180hp turbocharged engine with functional turbocharger, you might consider selling it to someone who wants a complete turbo engine. You could then use the funds received to purchase a complete 110hp or 140hp engine for your Corvair. Perhaps you could find someone who has a 140hp Corsa or Monza and wants a 180hp turbo engine in it. Maybe an engine trade could be arranged.

[miniman82]

I'm going to say the same thing I said in your post in the for sale forum: if you put dual carbs on it, you're going to be very disappointed in how it drives. Not only that, but to simply get it running correctly you'd need a distributor with a custom curve in it because it would then be a 180hp engine sans boost pressure- the wide open throttle curves of the turbo 180 distributor would be completely wrong for it at that point. The 180 has very late timing advance, and high base timing. What you'd need is something with around 16 to 18* base timing, 25* mechanical advance coming in around 2500 RPM/all in by 3200, and swapping the pressure retard for a vac advance can. If you try to use a 110hp distributor, it's gonna be lazy. Then there's the problem of tuning the carbs to play nice with the super low compression engine.

[Scott V]

a 95hp or 140 dizzy is a good choice for something like this. the car will run fine w/the turbo removed. it will feel pretty much like a 95hp engine.

-Scott V.

[bbodie52]

A side benefit with a non-turbo low-compression engine would be its ability to run on less-expensive REGULAR gasoline — unlike the turbo engine. However, the turbo engine — if the turbocharger and engine are in good running condition, with good compression readings and boost from the turbo — would be worth a significant amount of cash (unlike a 95 hp or even a 110 hp engine). So if the turbocharger is in good shape it would be a real waste to convert such a marketable engine into a 95hp "equivalent" while having to spend more money for Rochester carburetors, fuel lines, linkage and an appropriate distributor. Also, the turbo heads lack the automatic choke hardware to actuate the chokes on the Rochester carburetors. You should monitor the market for awhile on eBay and the CORSA ad section to see how the prices look for various serviceable Corvair engines. You might find an opportunity to unload the turbo engine at a good selling price, and purchase a normally aspirated engine, while keeping a good amount of cash in your pocket!