Yep a small port Air Gap clone. Itshould work great on a little 273 that likes to make power a little higher up on the tach. The old LD4B is great if you can find one.
273 upgrade to 4bbl?
- Thread starter BPTracing
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The only difference between Commando and a 2bbl 273 is cam compression and 4bbl you easily do 2 out of the 3, and run a better cam and intake than the factory, no reason you can't match or exceed factory commando while keeping it streetable.
I picked up a really solid 1967 Dart GT with the original 273 (auto) with 84k miles. I have been driving it quite a bit and love it!However, it doesn't have much power/acceleration. As time permits, I plan on upgrading to disk brakes, 4.5 bolt pattern wheels, and an 8-3/4 rear end. But until then I really don't want to do too much to the motor for now. I have been kicking around the idea of getting an edelbrock performer intake and small 4bbl to see if it gives it a little more "pep". The car already came with a dual exhaust system, so I figure the 2bbl is the main performance restriction currently. Just posting to hear if others have had experiences with this kind of upgrade.
A 273 is really not much different than any other small block. You should have the best of the small port heads. Run any intake (Weiand, Offy, factory, or Edelbrock), and a 273 factory AFB, Q-Jet, TQ, 340 AVS, AVS 2, Street Demon, or a small AFB. Replace the timing chain with a double roller. I always replace any 2 barrel with a 4 barrel carb and kickdown. Adjust your valves and set your timing to 10* BTDC. Beautiful Dart!
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Dale Davies
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Remember the old Fram filters adverts? Pay me now or pay me later. If you purchase questionable Chinesium crap made of recycled Yak turds, you get ****. Plus you are supporting a communist country that is adversarial not an ally.
Bite the bullet and get an Edelbrock made manifold. I would recommend the AVS2 500 carb also. Those will work real well for you on that beautiful car.
Regarding the 8.75" rear swap, I doubt with a 273 that you would hurt the stock rear, unless to get the 4.5" bolt pattern.
You are most of the way there and I bet a 4bbl and intake will really liven it up. It helps that it isn't a smogger LA - factory says 8.8:1 for a 67 273 2bbl. As mentioned before, some tuning with the distributor advance curve will also help. The AVSII carbs are a good choice and if the 650 works well on my 318, I bet a 500 would be perfect on a basically stock 273.
Please let us know how it turns out.
Exactly. One of the first things to bolt on any 2 barrel engine is a 4 barrel and decent intake. That and a little distributor tuning can make a difference. I have a 600 on my 273 and it works well.
Also you can upgrade your trans with a partial kickdown kit if yours does not have one. Add a Commando/Charger 4.2 kickdown lever and adjust the bands while you are at it.
lemondana
BlackDart
The part throttle kit really makes driving the small 273 much more enjoyable
BPTracing
Well-Known Member
Thanks again for replies, suggestions, and general knowledge from everyone!!
I got lucky! My buddy Ben Gorman at ProMax Carbs and Performance came through with a nice "small port" aluminum 4bbl intake!! No markings on it to know the year/brand, but it is dual plane.
Then I found an Edelbrock high flow aluminum water pump in the classified section, and I ordered the power front disk conversion kit from Right Stuff. Now all I need is a few extra days in the week to get things started!!
I got lucky! My buddy Ben Gorman at ProMax Carbs and Performance came through with a nice "small port" aluminum 4bbl intake!! No markings on it to know the year/brand, but it is dual plane.
Then I found an Edelbrock high flow aluminum water pump in the classified section, and I ordered the power front disk conversion kit from Right Stuff. Now all I need is a few extra days in the week to get things started!!
When you look into the 8 port openings are the ports split in half with a horizontal divider?
I see all the names and numbers have been removed.
Looks like an Offenhauser
No, not that sweet piece. The choke well is below the carb pad and the plenum matches an Offy.
It also looks like a 64-65 manifold and the hole in the rear plenum should not be there. If it is a 64-65 intake @eekvonzipper is looking for one.
here you go - Offenhauser Low Profile Single Quad manifold part# 5613. From the 2006 Performance Automotive Warehouse (PAW) catalog. This is a really old design as there are drilled and threaded carb mount holes for a Carter WCFB carb (used on many early Mopar 4bbl engines). Offenhauser unlike any of its competitors made (and still make) small runs of any of their manifolds for decades after they were introduced. It might be possible to order one of these new. I am pretty sure that this is a single plane (360 degree) manifold since all the runners are at the same level. If you want me to e-mail you the scan PM me your e-mail address - that way you can see more detail in the picture.
BPTracing
Well-Known Member
No. It is not a split port
BPTracing
Well-Known Member
BPTracing
Well-Known Member
Ok, I have found a part number, and it is a Offenhauser with everything on top ground off. BUT.... the listing I found on Summit for it, shows that is it for 64-65 273, which if I understand correctly is NOT an LA motor. So this will not fit my car?
Slantsix64
Well-Known Member
Four barrel will help also don’t for get to extend the kickdown 1 inch when going from 2 to 4 barrel. Your down fall is the gears which is probably 2.93 I got a 7.25 with ten inch drums with 3.55 gears that would pep it up.
If you look at the Offenhauser ad above here you will see the same intake is offered for 64-5 273s and 66 and up 273 and 318 LA motors (with your casting number on the first of those.
so the simple answer to your question is no. The 1964-5 273 is the first of the LA motors, but the intake bolts were smaller and at a slightly different angle. otherwise they are the same. you could drill out the bolt holes but the angle of the intake that you are tightening the bolts down on would be slanted and you might damage the manifold or nor seal well. people have done it successfully but it is a risk. There are tapered washers of various angles that can be bought and I think the right one is a 6 degree taper, that can correct the mating surfaces.
The thing is that there are always people on here trying to find intakes for early 273s and they are hard to find. Intakes for any LA 318 are correct for your 273 and can be had cheaply and easily. Rather than butcher your vintage early 273 intake, why not put it up for sale here on FABO and find a 318 manifold that would actually work better - and given your application find an actual dual plane manifold. You might even pocket some green given how plentiful the later manifolds are and how rare your is.
@65dartcharger
so the simple answer to your question is no. The 1964-5 273 is the first of the LA motors, but the intake bolts were smaller and at a slightly different angle. otherwise they are the same. you could drill out the bolt holes but the angle of the intake that you are tightening the bolts down on would be slanted and you might damage the manifold or nor seal well. people have done it successfully but it is a risk. There are tapered washers of various angles that can be bought and I think the right one is a 6 degree taper, that can correct the mating surfaces.
The thing is that there are always people on here trying to find intakes for early 273s and they are hard to find. Intakes for any LA 318 are correct for your 273 and can be had cheaply and easily. Rather than butcher your vintage early 273 intake, why not put it up for sale here on FABO and find a 318 manifold that would actually work better - and given your application find an actual dual plane manifold. You might even pocket some green given how plentiful the later manifolds are and how rare your is.
@65dartcharger
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@eekvonzipper was looking for a 64-65 4 barrel intake for his 273. As stated above, you can run any 318 intake without modifications.
Is that a #5489? Will a 3/8" bolt fit in the bolt holes?
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