Need advise on building a 1967 273....

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67yellowdartgt

67yellowdartgt

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I recently came across a numbers matching 1967 Dart GT with lots of documentation..After weeks of debating, I have decided to restore it keeping the factory 273 and not swapping to a new EFI motor. I will update the brakes, change the color, change the rear end (but keep it), and make some other changes. My question is, can I build the 273 into a strong motor? What setup is recommended to make it put down good reliable HP with the factory trans?

Thanks!
 
I'll bet those "302" casting heads would really shine on that motor. I believe they also have about the same size combustion chamber as the 273 heads, plus hardened seats. You may have some difficulty getting the pistons you want......I'm sure you can FIND pistons, maybe just not some nice 9.5 to 1's. I don't really know.....I was looking around about 7 or 8 years ago for some, and they didn't exist. You might want to get a more modern intake manifold also......that 4-barrel Commando unit is pretty Flintstone IMO. I'd also go a little light on the cam too.......maybe stock 340?
 
For the 273 Here is what I would do


First use the heads you got, just port them a bit, the 302 castings from a 318 are a great head, but I think you would have to notch the block for the bigger valves.

Run LD4B edelbrock intake, it has small ports for your heads but flows good #'s, better than a lot of stuff out there.

Pistons can be had at Hughesengines.com, with the High Compression Dome that you will want, LOOK IN THE RARE ENGINES PARTS section or you wont find them for your 273.

Comp Cams sells some Xtreme Energy Cams, I think the 268 would be a hot little cam for a 273... You want a cam with lots of lift, you are aiming to get high velocity from the motor. The goal is to use that velocity to make up for the small ports/valves/displacement.

Do a search on the site for "66 dart D stock" or "275 HP 273" to see how Ma Mopar got them to make some power. There are lots of posts with the same question you have just asked...


That being said...

The 273 may make good HP per CI, but it will never have the torque that most guys want to get off the line. You will have to really twist it up to get good power (which it will like) but you will want lots of gear, and a really loose converter if you are running an auto.
 
Thanks....That has been a great help! Sounds perfect for a good looking pro touring cruiser...
 
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