I've had my 1964 Convertible for a couple of years now, and would like to fix some of the drivability problems. There is no documentation and the car has been modified.

The engine runs OK, strong in high RPMs, but has some drivability issues, mostly related to tune. It doesn't have a vacuum advance on the dual point distributor. Compression is great in 7 cylinders, with one cylinder down slightly, but still in spec. It holds good oil pressure. It has a Holly 2818 carb on a Weiand aluminum manifold. It has an M20 transmission and 4:11 rear.

To start with I'm trying to figure out what to do with the engine. It is a non numbers matching block with no serial number. The casting number is 3959512. What are the differences between the block I have and the 3782870 casting the car should have? Is it worth working with the block I have or should I shop for an engine with different casting number?

I would like to keep the engine period correct.

TIA, Gene

 

Exactly what Weiand intake is on the engine? Dual plane or single plane. You would benefit by converting the points over to electronic and put a vacuum advance in. I don't know the particulars of that Holley. Not knowing what cam is in the engine will be a factor. It may be suited for 4:11 gears, or may not be. I guess if you must try to be "period correct" getting a 870 block would do it and you could build an engine that runs well. The problem I see will be the 4:11 gears. If you intend to just cruise around Southern Maryland at speeds below 55 you would be ok. How sure are you that you have 4:11 gears? As far as I know, the only difference between the blocks is the casting number. They are both 2-bolt used between '62 and '67. The 512 runs '62-'63, the 870 '62-'67, then it depends on the intended vehicle. If you start from scratch, include changing the 4:11 to 3:36 or 3:55. Dennis

 

Some 1965 Corvettes used the 512 block. If you're not concerned with numbers, then the 512 block should be a good foundation, especially since it seems to be healthy.

Bluestripe is giving you good advice. I would add that the carburetor is likely contributing to driveability issues. Replace it with a new Quick Fuel 650 carb and you'll think you have a new car. Trust me on this. If your intake is single plane, then the 2818 won't like it as much as the QF carb will. I wouldn't change the intake. I'd do the distributor and carb first.

Instead of changing diff gears, I'd go with a Legend 5 speed. Do you know what your cam is? How high is high RPMs? Elaborate on your driveability issues.

Here is the best distributor for your engine:
http://www.summitracing.com/parts/msd-8572

 

Thanks Dennis, exactly the info I'm looking for on the block. I'll do some research on the intake manifold. The carb is the same as was stock on the 365hp engine. I think the car was used for drag racing by the PO running full throttle most of the time, but I'm just guessing. There is no documentation, but the dealer said the PO dragged the car. The dealer has gone out of business and I haven't been able to hunt down the PO.

The cam is not a solid lifter, but lopes a lot at idle.

Changing out the distributor is in my plan. I think adding vacuum advance will help the drivability a lot. I would like to change out the 4:11 gearing too.

 

I've had some issues with the carb, sticking secondary float. I saw a big improvement with the sticking by using LL100. An expensive fix, but I mix it with pump gas. It runs very well up around 5k RPM. It seems sluggish off idle and below 3k RPM. Don't know the cam, hydralic with a noticeable lope at idle.

Gene

 

Gene,
1. The best improvement for drivability in your case would be adding vacuum advance and dialing in your distributor.
2. With an M20 and 4.11 gearing, there should be no lag problem, but apparently there is; if I make the assumption that you have the 30-30 Duntov cam (or hydraulic equivalent), sluggish starts are annoying, but with your low total gearing (2.52 x 4.11 = 10.35), you have the right amount of gearing and shouldn't have launch difficulty unless there are other problems.

Here are a few ideas: Make sure your 2818 carb is correctly built and it doesn't have some Bubba arrangement to open the secondaries prematurely. Secondly, get a good 2-plane manifold like the stock L76 aluminum high rise, or the later LT1 manifold which will improve low end torque over a single plane manifold.
3. Figure out how you want the car to perform and pick a better cam. I would guess that you have way too much duration for what you want.
4. Your engine block is fine - it is period correct, but even if it were a 2870 block, it's still not the original motor.
5. The MSD distributor, although it will work well, is too tall to use the stock ignition shielding. You may want to consider one which has the original style socket style ignition cap.

Good luck with your project!

 

I was trying to figure out what my priorities are. Not worrying about the foundation (engine block) is a good step forward.

That's my plan, to start with the distributor. Now I need to figure out what I want to replace it with. I know that's a hot topic on the forum. I don't want to start a problem topic.

 

Car will NEVER run right without a vacuum advance. Get the distributer set up properly [absolutely dump the dual points] as a base improvement then go from there...




A new holley 600 is a few dollars over $300 or send the 2818 out for a nice restore to Eric for probably about the same.