I hope this is useful to others, it's a complex story. I was having starting issues and hesitation issues with my fuel flow in the '64 Deville and posted here. Various folks gave me excellent info on accelerator pump, filters, vacuum, etc, but I decided just a new carb was the way to go. I wanted a fix, not tweaks.
Seemed easy, as I've exchanged carbs on a number of cars over the years. You undo 4 nuts and do a little tuning, it takes half an hour.
There was a debate between replacement Carter AFB vs the newer Edelbrock 1406, and I was convinced to do the Edelbrock. I ordered it from Amazon for about $375 and put it on. It leaked, and nothing could fix that. Edelbrock then told me I was supposed to put in an adapter, which I then bought separately, though I did not understand why I would need it since the footprint of the Carter and Edelbrock appeared identical, and used of course the same gasket.
I could not get the carb to run right, and thank you Jason and others for advice on that. Giving up, I ordered a rebuilt Carter, which would be closer to bolting on, an even swap.
I ordered the Carter from a rude, nasty guy in Texas who seemed to have done thousands of them. I could not get the car to idle. He had a "no return" policy but when I called for advice, he more or less called me an idiot and said "send it back."
At this point, I went to a highly competent local mechanic who said no prob, I will get this done for you. Soon enough, he determined that my intake manifold was cracked in more than one place. By this time, I'd been trying to swap the carb for many weeks and had been without the use of my convertible car during the best weather of the year.
I looked online for an intake manifold, and though many people said it should be around $200, I only found a decent one at Cadillac King in Pacoima, CA for $400. So I ordered it. I did not know that Cadillac King would not send it out for 10 days. Apparently they removed it from a car, inspected it, and painted in the correct engine blue color. So it took 2-3 weeks to get the thing, more downtime for the car.
The manifold showed up and was installed. Using Jason's instructions, the mechanic made a custom piece to block part of the intake, blocked off choke vaccum(since the 1406 has an electric choke), and the car was ready.
It drives MUCH BETTER. It starts INSTANTLY. I used to have to pump it 15-20 times and still probably start is 3 times and also let it warm up for 5 minutes. None of that is needed now.
SURPRISE BONUS--CAR IS QUIETER. I had chugging noise like an old jalopy, and car drove OK when warm and I thought I needed exhaust work. But the new intake manifold cut the chugging noise way down and the car sounds more like the quiet machine it was when new, though not quite at that low level. But I'll take it!
It's wonderful for the car to start quickly, drive right off, and not have hesitation at stop lights. Very smooth. To those of you who urged me to see it through on the Edelbrock and get a pro to help, thank you, glad I did just that. The Carter would have been OK, I'll never know, but this Edel is brand new, not rebuilt, and I'm very happy with what feels like a new(er) car.
I still have been unable to locate the rings that allow the air cleaner to mount on top of the 1406 but somehow I'll get that done. Autozone is the supposed source but mine has no idea what I'm talking about. I'm driving with no air cleaner for a few days.
The 1406 conversion has many steps involved and took many week, in my case. The money was significant, but it's of less consequence than having the car run right. Only issue now is not transmission kickdown switch. On the highway, if you floor the car, it makes a roaring, sucking noise but does not rocket ahead. I can live without it, but I'm told there is a way to mount that kickdown switch using some mounting platform you buy. I haven't seen one yet and I think Jason said he decided to go without the switch and doesn't miss it.
Oh, one other thing! The car RUNS COOLER WITH THE NEW INTAKE MANIFOLD. I am not up on the relationship between intake vacuum and engine temp, but it's August and the temp gauge runs closer to 1/4 where it used to run 1/2 to 3/4 on a hot day. I had to pull out of a parade once between it was pinned to hot. I got a new $200 aluminum radiator, a great deal, and that helped but did not completely solve. Now I have a cool-running 429.
Mine is a really excellent version in great, original shape. Next stop is perhaps new springs. The car is bouncy and new shocks didn't help.
THANK YOU SO MUCH to Jason and Tony and anyone who weighed in to help. This carb swap is a good idea, and so is checking your intake manifold to make sure it's intact. No doubt after 50 years, a number of them have hairline cracks in them. I don't know if that can be repaired but I have my old one if it's of use to anyone. You'd have to do some welds or something. Some people use epoxy but that would seem stopgap at best.
I am glad you got it set up. I just got an intake from Jason, bought the Edelbrock and spacer. Jason mentioned he used a thicker intake gasket and not the thin metal one like the Felpro gasket. Does anyone know a brand and part # for the the thicker gasket? thanks
Pls get an air cleaner on the car
You are in danger of a motor fire without one
Go to your local auto store and they will have one that will fits
You wana ask me how i know ?
I have a --Spectra air cleaner --on my Edelbrock 1406
It is the same as the much more expesive air filter ( top of the line air cleaner ) that is very popular that i cannot remember the name of right now
The Spectra come in blue to match the engine and i really like mine ( $20 and lifetime )
Better breathing carb equals more HP
Any air leak into the intake will make the engine alway run hot As you have experienced
Very happy the car sounds like it is running as intended and thats always great
The old intake can be welded to repair it
Do be sure that your vacuum advance is connected to the driver side vacuum port on the front of the carb and that the other side is plugged off
Doing that will -if not done already ( as it sould be ) wili give you the intended best performance ignition timing to enjoy your cars power
This is one thing built into the New Edelbrock carb ( the performance people ) that the Carter carb does not afford its owner
Do enjoy your fantastic running Cadillac -- when they are good they are real good
Tony, I think you mean Spectre air cleaner, not Spectra? You'd rather do that than get a ring adapter and have the original Cadillac air cleaner on there? I have not found that adapter yet, not as easy as people have said.
Russ on this site sells the adapter for the stock air cleaner --i think
He should respond shortly
I have no need to have the stock air cleaner on my own car
I think the stock air cleaner would restrict air flow more than an after market more free flowing type
A big carb that needs to breath
I have used an after market one for over 35 years
Looks nice when the hood is open
I have the custom made air cleaner adaptors for the carb conversion. Made from a high temp resistant material, these will withstand the under hood temps. 50.00 plus shipping.
Please email me at email@example.com
I bought the adapter from Russ when I went to fuel injection. Not cheap but very solid piece
Thanks to all. Looking into this tomorrow. Have not even tried to fit the standard air cleaner housing on the new Edelbrock so I have to look and see the degree of mismatch and then figure it out, and thanks to Russ for that option!