Welcome, there are definitely a lot of opinions here. I have a 273 commando and plan on keeping it original. I'm not planning on selling the car. Hoping to have the paint complete soon. I just wanted a different car to cruise around, not to race.
WELCOME ! AS you can read by the response there are as many opinions as there are members . I have been in the Mopar parts business since 1984 and heard thousands of people recite both sides of the issue . As far as value goes , changing the engine will NOT devalue the car . Example : putting a 426 Hemi in it makes it worth less ? Hogwash ! A 273 leaves a lot on the table but if you want to leave it , good for you . If you want to go with a late 318 or 360 , good for you . Economics is a horse of another color . An "LA" 318/360 dressed like a 273/2bbl. is cool . A Magnum 318/360 is cool . Much more economical . For cruising "torque" is your friend and the 273 doesn't have much . IMO Later, TOM
Congrats on finding a 340... I looked around for one for the dart but they are hard to find. My '70 CUDA was a 340 car, but the guy I bought it from replaced it with a 440 4 barrel (and sold the original 340). I just upped it to the Six Pack with an original '70 intake and new repro Holley Carbs and it's running like a beast. I wish that he had kept the 340 and that it had come with the CUDA which would have solved my problem. I would have tossed it in the Dart and put the 273 in Storage.I yanked my original 67 273 engine and trans that needed rebuilding and put a 340 in it. If the next owner wants to rebuild it back to stock I have all of the hard to find stuff in storage. The head gaskets are hard to find for 273's. IF you want to rehook up all the a/c stuff you need to stay with the 69 and older timing cover,pullies,water pump,brackets. The compressor is designed to fit the 69 and later water pumps (cast iron),70-up is aluminum and requires different compressor brackets,pullies,alt bracket,radiator,hoses,shroud.
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I yanked my original 67 273 engine and trans that needed rebuilding and put a 340 in it. If the next owner wants to rebuild it back to stock I have all of the hard to find stuff in storage. The head gaskets are hard to find for 273's. IF you want to rehook up all the a/c stuff you need to stay with the 69 and older timing cover,pullies,water pump,brackets. The compressor is designed to fit the 69 and later water pumps (cast iron),70-up is aluminum and requires different compressor brackets,pullies,alt bracket,radiator,hoses,shroud.
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May be too much for the OP's wife to enjoy. LOLMy car now gets sideways when it's not raining.
Since the OP has a '68 273 then the 318 should drop in unless the '68 273 is a very early '68' and has a small crank register hole perchance. The one thing to be aware of is that the hole in the back of the crankshaft where the torque converter snout fits in (crank register), is larger in the '68's and later.
Yes, there are different 318 pistons out there (truck vs car) but they are all low compression engines; the trucks are just lower. This makes them 'soft' in the lower RPM's ranges; i.e.; not much low end torque. It is very desirable from a performance standpoint to correct this issue for the 318's, so a custom build speaks more to that. The same really applies to 360's. The later Magnu versions of these engines fixed that low CR issue to some degree, so IMHO are more desirable from a performance standpoint.
For the wife, I think I'd think 318. You have a light car to start with, and something that takes a lot of throttle management may not make here happy.... but you know here likes and dislikes better than us. I have an acquaintance who went from a '68 273 to a 400+ CI stroker, and he says it ruined the car as a family 'go to the drive-in on Saturday night' easy driver car.
The car 'dieing' randomly is a much different matter than the engine....look at the electrical stuff and brakes first.
Well... in the last 12 hours since my 1st post I have learned a great deal - thank guys - all of you:
1) I have learned about all of the above and options.
2) I have learned that when you have a conversation with your wife 3 weeks ago and finally get time to move on the project - take time to recap.
3) We just returned from lunch - I gave her a run down of what you guys have told me, we talk Torque and Horsepower - she has been with me in the CUDA - not really Hot Rodding, but bumping the throttle on occasion and popping her neck back (lol) - so she gets it... So after a lengthy conversation on options she say, "I want my 273 rebuilt. I don't want to go fast, I want to go slow and cruise. I'm cute and want everyone to see me. If I want to be a blur, I will ride with you in your CUDA". And as a good husband does, I asked her permission to quote her verbatim and got it. That's the funniest line I have ever heard! lol. So I give up. I tried to get her to go with a bigger engine but if she want to "go slow" - as well as the fact that she has some nostalgic connection to 'keeping the original motor' for some reason... then I guess I will fork out the extra Cash to build the Little Engine Than Could (break me). So, I will search the Forums for a Parts List, to rebuild kit, and all the things I will need (unless someone has a neat down and dirty grocery list with companies to buy the parts from) that would be Awesome as she is wearing me out - now I just want to get it built! I will at the least make it where she can burn any type of gas (Ethanol) so I will need those special parts to do that. Thank you guys again for taking the time out of your day to give me some ideas... Here's to rebuilding a 273.
With the lower compression 2 BBL Egge L2221 pistons you would have to deck the block .040" to get them to zero deck, and then you would still only have 8.4:1 static CR with .027" thick Cometic gaskets (assuming they make 273 gaksets from that thin MLS material) and 302 heads. IMHO shave 302 those heads another .040" to get to around a58 cc chamber..... then you are a 9:1. But it sure would be easier to use the Egge L2222's and not bother to deck the block.Could always make a 300 or 336 out of the 273 with a 3.58" or 4" stroke lol
Since your stuck with the 273 I'd just use the stock flat top pistons you can get and zero deck add 318's 302 heads and a .040" gasket with a 500 cfm performer carb and intake and a 250 ish cam and duals and call it a day.
I always wanted to see how a zero deck flat top 273 with small chambered heads would work..Could always make a 300 or 336 out of the 273 with a 3.58" or 4" stroke lol
Since your stuck with the 273 I'd just use the stock flat top pistons you can get and zero deck add 318's 302 heads and a .040" gasket with a 500 cfm performer carb and intake and a 250 ish cam and duals and call it a day.
Yes... I just meant gas with ethanol v/s100% Gas.With the lower compression 2 BBL Egge L2221 pistons you would have to deck the block .040" to get them to zero deck, and then you would still only have 8.4:1 static CR with .027" thick Cometic gaskets (assuming they make 273 gaksets from that thin MLS material) and 302 heads. IMHO shave 302 those heads another .040" to get to around a58 cc chamber..... then you are a 9:1. But it sure would be easier to use the Egge L2222's and not bother to deck the block.
The OP has a '68 2 BBL 273 and that would have the 675 heads IIRC, with around 68 cc chambers. So smaller chambered heads sure do make sense.
OP, you have about the clearest marching orders you could ever get! They make complete sense to me LOL
BTW, OP, what do you mean about burning ethanol? Do you just mean burn standard gas with up to 10% ethanol?