New carb for 1965 273 4-bbl hi-po package

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Stumpy

Stumpy

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I’m noodling replacing the Edelbrock 1405 that the previous owner put on my mostly stock 1965 Dart 273 hi-po option with the original intake. I prefer drivability over performance and keeping it looking mostly stock and I’m thinking an auto choke 500cfm carb would be a good fit for this motor. Looking for suggestions.

I’ve got the original carb but it’s garbage. I could try to find an original core worth rebuilding but I’m not trying to restore this car to original.

I looked at previous threads on this but they are years old and there might be better options now.

Thanks.

41206BD0-3272-485D-BC0E-80364DDCCDA8.jpeg
 
My original carb was toast as well. I put on a 1405 and it has been trouble free for 10+ years now. You won't notice much difference in the 500 vs the 600. I would leave it as is. You can always tune your 600 to make it work better. Metering rods and springs do a lot for those carbs.
 
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Right now my problems with it is a slight surging at low speed cruise (25 mph or so) and hard start when hot (acting like flooded). Yesterday I warmed it up and pulled the air cleaner off, turned it off and could see (and smell) the gas fumes coming off the carb. I read somewhere that a riser might help. When I rev’d it up and watched and it seems like the secondaries are not engaging. What rpms do the secondaries engage on a 1405?

I was thinking about rebuilding it but have never rebuilt a carb before. I’ve rejetted and adjusted plenty. I’m game at giving rebuilding a try though.
 
Stumpy said:
Right now my problems with it is a slight surging at low speed cruise (25 mph or so) and hard start when hot (acting like flooded). Yesterday I warmed it up and pulled the air cleaner off, turned it off and could see (and smell) the gas fumes coming off the carb. I read somewhere that a riser might help. When I rev’d it up and watched and it seems like the secondaries are not engaging. What rpms do the secondaries engage on a 1405?

I was thinking about rebuilding it but have never rebuilt a carb before. I’ve rejetted and adjusted plenty. I’m game at giving rebuilding a try though.
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Surging could be a lot of things. Kind of hard to diagnose. The hot soak/hard start is common with the oem carb or the Edelbrock's. A thick spacer under the carb can help, a return fuel system can help, and a electric priming pump can also help. You should be able to check the secondaries opening by propping the secondary air butterfly open and opening the throttle. Your throttle might not be opening far enough. Fairly common when switching to a Edelbrock from a OEM carb.
 
Stumpy said:
I’m noodling replacing the Edelbrock 1405 that the previous owner put on my mostly stock 1965 Dart 273 hi-po option with the original intake. I prefer drivability over performance and keeping it looking mostly stock and I’m thinking an auto choke 500cfm carb would be a good fit for this motor. Looking for suggestions.

I’ve got the original carb but it’s garbage. I could try to find an original core worth rebuilding but I’m not trying to restore this car to original.

I looked at previous threads on this but they are years old and there might be better options now.

Thanks.

View attachment 1715788155
Click to expand...
Will that breather fit the Edelbrock ,i sent my original to Toronto to be rebuilt ,they replace the shaft and new bushings and rebuilt it .


DSCF1901.JPG
 
toolmanmike said:
Surging could be a lot of things. Kind of hard to diagnose. The hot soak/hard start is common with the oem carb or the Edelbrock's. A thick spacer under the carb can help, a return fuel system can help, and a electric priming pump can also help. You should be able to check the secondaries opening by propping the secondary air butterfly open and opening the throttle. Your throttle might not be opening far enough. Fairly common when switching to a Edelbrock from a OEM carb.
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1/2” or 1” spacer? I need to measure clearance with original air cleaner.
 
try tony's mopar parts, they have OE carbs listed. the sec in your carb are heavily weighted, has to be modified to make them open . been there done that.
 
If the throttle shafts are still tight and don't leak much, rebuilding the factory AFB or the aftermarket Edelbrocks are fairly easy to do. Just a good overhaul set and some spray carb cleaner is about all you need.... well....and a bit of patience and keeping everything scrupulously clean.
 
On the hard starting when warm, don't disagree on the recommendations for a heat spacer under the carb, but have you checked your heat riser valve in the passenger side exhaust manifold? Could be stuck shut and sending virtually all of the right side exhaust through the hear riser passage in the head, underneath the intake manifold and out the driver's side. That will really heat up the intake manifold (as well as greatly restricting the exhaust flow). If it is stuck closed (the one on my 56 Plymouth was), eliminate the valve. In fact, eliminate it anyway unless you so a lot of really cold weather driving. Even better, pull the intake manifold and block the heat crossover, which runs directly under the carb. That will significantly cool the intake manifold and reduce fuel percolation after shutoff, plus generally add power from a cooler intake.
 
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Automatic trans or stick? Makes a difference on how fast the throttle shafts wear.
 
Stumpy said:
4-speed
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Probably worn out. Think of how many times the throttle opens and closes through 4 speeds and 3 gear changes in 100,000 miles. 1/3 of the wear with a automatic.
 
Some comments.
- You have the BEST carb already for drivability, an AFB style carb.
- Rare to see t/shafts wear out on Carter/Edel 4bbl carbs because of the large amount of surface area the shaft has in the alum body. All the Chrysler cars I have worked on had the throttle return spring connected to a bracket forward of the carb; this helped equalise the pull on the t/shaft to minimise wear.
- surging at cruise could be many things. Excessive ign timing [ vac adv hooked up? ], low float level, lean mixture, weak ign/spark etc.
 
Secondaries not opening. Unlikely to see that by winging the throttle because the secs are dependant on air flow; the 273 is a small engine & has less airflow than bigger engines.
 
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