1964 L76 Induction

[Ray A.]

Comparing Noland Adams' photos (Vol. 2, pages 226 a 229) to my induction system and it is clear I have issues, but I remain puzzled about the fix. There is no vacuum line from the distributor to the carb and both are capped. In addition, the line from the top rear of the intake manifold is capped in the book, but runs to the crankcase vent(?) on my car. I assume that should be to the air cleaner assembly? Are these differences because my car does not have vacuum assisted brakes, or is it just plain wrong? The radiator gooseneck and oil filler neck also look wrong, but I'll get to those later. Note that I also don't have a fuel filter. My car is a VERY early 1964, so I don't know whether to use the black or unfinished filter (1963 or 1964?). Guidance and critique welcomed and appreciated. Thanks.

[Gene M.]

Re: 1964 L76 Induction

First of all do you have 870 block? An 870 block has a vent that goes to the air cleaner. You should have manifold vacuum advance to distributor, at carb base fitting.

As for power brakes the master cylinder is a replacement. So I can't tell if you had power brakes or not. Look to see if the nut plate is there for the booster.

Yes I would agree you have some correctness issues. Are you interested in NCRS correct or just have the engine run as it should?

[Keith B.]

Re: 1964 L76 Induction

what are the numbers on the carb?

[Ray A.]

Re: 1964 L76 Induction

Not sure what an 870 block is. There are no signs that there was ever a brake booster installed. There is no provision for vacuum at the carb base, but there is a plug where the Adams reference shows a vacuum line could (should?) be.

The carburetor is 3849804, 2818-1, 723. Intake manifold is 3844461.

The clearest photos are of a "prototype" engine which shows the large vent on the top center rear of the intake manifold plugged. The photos on page 228 show a hose attached to this vent but there is no clue to the routing. On my car the hose goes from this vent to a vent on the top the block, where I assume the crankcase tube to the air cleaner might be on (some?) engines. The engine on page 228 is a power brake car, so maybe that manifold hose is connected to the booster?

[Keith B.]

Re: 1964 L76 Induction

By 870 block he is referring to the block casting number that can be found on the back of the block on the drivers side on the flange where the bellhousing mounts. 870 is the last three digits of the correct block

[Ed S.]

Re: 1964 L76 Induction

Carburetor 3849804, 2818-1 is a service replacement - not sure off the top of my head what the date (723) translates to (my 513 is a 65, Jan 3; your 723 might be 67, Feb 3); your intake manifold is correct for a '64 L76.

[Duke W.]

Re: 1964 L76 Induction

It looks like Bubba has been working on your car and has removed the PCV system. Your best reference is the AIM, which shows all the missing parts and how they are installed.

The replacement carb should have full manifold vacuum at the plugged port, but you need to verify that with a vacuum gage. The VAC should be a OE 236 16 or a B28 replacement, but you need to check that it meets spec, start at 4", fully deployed at 8".

If all is as above, then it's just a matter of running a length of 1/8" vacuum tubing to at least get it functional, and the AIM will show if there is a small length of steel pipe as on '63 engines, but I'm not sure about '64.

It also appears that the VAC is butted up against the coil bracket, which probably means the gear is installed 180 deg. out of the proper orientation, which is the dimple in the drive gear should be pointed the same direction as the rotor tip.

Duke

[Joe L.]

Re: 1964 L76 Induction

Ray------

In addition to what others have mentioned, the thermostat housing is definitely wrong although it looks to be functionally OK. However, the hose looks like it might be non-molded and looks "pinched" at the bend. Install a correct thermostat housing and correct molded hose.

Looks like the fuel inlet line has a short length of rubber hose at the carb. Get rid of that with a correct fuel line.

Something really strange that I see is that the waterpump has a plugged external bypass fitting. Your application is one of the few small block applications that actually uses external bypass. So, why anyone would eliminate it is beyond me. There should be a molded hose with appropriate fittings that goes between the waterpump bypass and the left front of the intake manifold.

Apparently, someone has converted the ignition system to all centrifugal advance and eliminated the vacuum advance. This is a BAD thing for a street engine.

[Dino L.]

Re: 1964 L76 Induction

In addition to all the good advice.... your oil fill tube and cap are not factory, there is a metered orifice 90 degree fitting on the driver side carb with a rubber hose that goes to the filler tube, the crankcase vent next to the distributor has a large hose that attaches to the base of the air cleaner. Your choke tube is missing the clean air portion that attaches to the bottom of passenger exhaust manifold and there is a rubber hose that routes between exh manifold and valve cover and plugs into the air cleaner base. Your temp sensor wire is routed on wrong side and is missing 2 clips under valve cover bolts. You should have an idler pulley and large thick alternator pulley. Your fan looks like it is not far enough in the shroud.... without the advance your car is overheating at idle? Get the AIM and look at the L 76 option page it's all there. You need a black G40 filter in Chrome bracket, and chrome lines , rubber to carb.

[Ray A.]

Re: 1964 L76 Induction

Excellent input, thank you all. The first thing I will do after writing this reply is purchase the AIM (after a little browsing I found it - I'm starting to learn some of the lingo around here).

My primary objective is to enjoy the car so I want to make sure it is running right, but as long as I'm in there I might as well use correct parts whenever possible. "Possible" means I will not likely go look for a correct 1963 date stamp carburetor and will just restore the -1 factory service model. But I will make as many of the other corrections as I can.

Ordering the AIM now and preparing to get a parts order ready.

[Duke W.]

Re: 1964 L76 Induction

You should also buy a 1963 Corvette Shop Manual and the 1964 Supplement.

[Tom D.]

Re: 1964 L76 Induction

Ray: I see by your NCRS number that you didn't join as early as some of the guys listed herein. I just wanted to say welcome to the club.

This is also to let you know that it's nice to hear from someone who's learning about "midyears" (now called C2 Corvettes). Many of us go back to the days when the C2 Corvettes were in the middle, between the first generation and the "sharks" (now called C3s). Hence the nickname "mid-years".

[Ray A.]

Re: 1964 L76 Induction

Gene, I've verified the block is the original 870 with the correct original (not a repop) serial number. Thanks. Once I get everything else sorted out I will begin a search for the correct master cylinder.

First of all do you have 870 block? An 870 block has a vent that goes to the air cleaner. You should have manifold vacuum advance to distributor, at carb base fitting.

As for power brakes the master cylinder is a replacement. So I can't tell if you had power brakes or not. Look to see if the nut plate is there for the booster.

Yes I would agree you have some correctness issues. Are you interested in NCRS correct or just have the engine run as it should?

[Ray A.]

Re: 1964 L76 Induction

Duke, verified that the distributor is correctly installed and oriented, but it seems that my coil has been relocated to a non-original location. I'll verify after some of the documents I ordered on the recommendations of this post have arrived. The distributor also seems to still be a vacuum advance unit but, again, to be verified when manuals arrive. In the meantime I've ordered the correct lines, brackets, etc. to reinstall the vacuum connection between dizzy and carb.

The hose between the intake and block will also be removed. I have the pipe and associated hardware between block and air cleaner coming. Now I just need to find the correct plug for the intake manifold. There must've been a factory solid plug (as shown in the Adams reference) for cars without boosted brakes but I have not been able to find any reference to it. Also still looking for the routing of the small diameter hose from the bottom of the air cleaner to the (carb?).

Thanks for the observations and input.

[Ray A.]

Re: 1964 L76 Induction

Thanks for your observations Joe! I will definitely take care of the water outlet goose neck and water pump bypass. I just need to verify which water pump I have (it looks like I need to pull the pulley, darn it!), or at least what size the tapped hole is. The upper radiator hose looks funky in the photo, but it is indeed a molded hose and not kinked. When I get the correct hardware I will also replace that hose anyway. Thanks again for the careful look.