Worth it to build my 273?

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Shane65

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Hello everyone,

I'm new to the forum, and i'm in the process of fixing up a 65 barracuda. Seems like most people swap in a 340 or 360, but I'm curious what I can do with the 273, if it's worth it...

My goal is to have a fast street car that I occasionally take to the track. High 12's would be plenty quick for me, I'm not trying to break any records. Is this possible in an all motor 273?

Anyone have links to 273 builds, or videos?
 
hate to say this...but if you want a fast street car...cubic inches is going to play the best...a 273 is giving 90 cubic inches away to a 360...the 360 has better cylinder heads....

360 engine...can be had cheap...and will cost you less to build then the 273 since the availability of pistons ...
 
High 12's is ambitious for any engine. I recently read that the 1/4 mile times for the top-line factory 340 A-bodies were ~13.5 sec back in the day. That was with factory bias tires. I think to get there, you will need wide drag tires, perhaps requiring tubbed rear wheel wells, and a stronger rear end (8-1/4 or 8-3/4) and maybe a custom tranny. Of course, now you are getting to a drag-only toy, not a daily driver. There is more pride in going fast in a 273. Some guys are in the 11's with a slant six, but not cheaply (turbo, etc).
 
hi, I looked up prices, pistons will cost bout the same, rest of parts cost same, as they're for same family of motor.the 360 is NOT the answer for everything!! you'll need gears and suspension, to get close to 12 sec. back in 72, ran a stock 235/273 , with gears n slicks,headers ran 13.31 it was street drivable. didn't drive on highway though. the chassis gets you E.T, motor gets you MPH. just for information, there is a 235/273 that runs in stock eliminator , it runs 11.70, its NOT drivable on street. mid 13 would be very fast for a 273 like you envision. just food for thought.
 
perfacar said:
hi, I looked up prices, pistons will cost bout the same, rest of parts cost same, as they're for same family of motor.the 360 is NOT the answer for everything!! you'll need gears and suspension, to get close to 12 sec. back in 72, ran a stock 235/273 , with gears n slicks,headers ran 13.31 it was street drivable. didn't drive on highway though. the chassis gets you E.T, motor gets you MPH. just for information, there is a 235/273 that runs in stock eliminator , it runs 11.70, its NOT drivable on street. mid 13 would be very fast for a 273 like you envision. just food for thought.
Click to expand...

and there are alot racers in stock eliminator with 360s in heavier cars that run high 10.....do the math...anyway you shake it out the 360 is going to be faster... sorry....
 
70aarcuda said:
and there are alot racers in stock eliminator with 360s in heavier cars that run high 10.....do the math...anyway you shake it out the 360 is going to be faster... sorry....
Click to expand...
x2 360=fast
 
I always wondered if a 273 with Magnum heads would make a good-running street motor.
 
theres a reason they got rid of the 273. 318 or 360 is the way to go there is the 340 too
 
Put the 273 under the bench. start with a early 360 or 340 . 75 and newer 360's are weak and should only be used if you can't find an early one. Also stay with a lower mold number. your chances for more concentric cylinders in a sonic test is better.The more even your walls are the less deformity under heat and stress. 340-1 being the best 340-2 next and so on.
 
If you build a 273 the same way you'd build a 360, the 273 will not make as much power. If you build a 273 to take advantage of its strengths, (lighter components so it's easier to spin faster, smaller size makes it easier to build adequate heads, smaller bore and closed chamber heads that are less prone to detonation) it'll still make less torque, but HP may be closer.

Now if you build the whole car with the above in mind it is possible to achieve near the same or even better track performance, but the car will not be nearly as pleasant to drive on the street and your attention to details must be spot on.
 
I like the little 273 but would not recommend spending money to rebuild it unless your restoring a 273 Commando engine for an original car or clone. You can dress up a 318, 340, or 360 to look just like a 273 and as has already been said you'll have better heads, more cubic inches, and most likely a faster car for the same money or less.
 
Hey Shane if you decide to go with the 273 I have one up for sale here on the forum. It's been broken in on a stand but I never ran it in my car. My friend gave me a 440 so I decided to go that route. It's making around 300 hp here is the link to my add:
http://longisland.craigslist.org/pts/2724858660.html
if you are interested make me a fair offer I have lots of machine work done to it the compression is at 10:5:1. Good luck with any decisions you make. P.S. the date on the block is 9/28/65. This may fit the bill. I also have a video of it running on the stand.
 
Shane65 said:
Hello everyone,

I'm new to the forum, and i'm in the process of fixing up a 65 barracuda. Seems like most people swap in a 340 or 360, but I'm curious what I can do with the 273, if it's worth it...

My goal is to have a fast street car that I occasionally take to the track. High 12's would be plenty quick for me, I'm not trying to break any records. Is this possible in an all motor 273?

Anyone have links to 273 builds, or videos?
Click to expand...

Anyone who has had a 273 Commando loved it. They have their place, Efficiency + Power. 12's, you would probably be happier with a 318, 340, or 360. I personally prefer the 318 and 340 over the 360. You can run 12's with the 273 but they are a bear on the street. A 65 Barracuda has a lot of drawbacks, 10 in clutch, 904 Auto trans, small rear wheel wells, and a small engine compartment. That is why I stayed with a 273 in a 66 Barracuda. It is plenty fast. I'm not going to put up with headers, 4:10 gears and slicks. I don't need to do 12's at the track. It is best to figure out what you want and go from there. Toolman did a nice build on his 273.
 
I am building my 273 to 235 Hp + specs but I am the 2nd owner of an original car and wanted to keep the original 273 engine. I am building the 904 to perform and adding an 8 1/4 3:21 shur grip differential with LBP for the added Hp. I will be road tripping my car a lot when finished but may time it one time for kicks.
DR
 
thanks for the responses guys...

Okay, so IF i decide to swap out the engine to a 340 or 360, it'll work with my the manual 4 speed that's in there right? Probably need a better cluth, any recommendations?
 
yep, small block is a small block. You should look into putting a 10 1/2" clutch in there. What would be neat is to do a supercharged 273..............

Quight possiably future plans for ours :)
 
Shane65 said:
thanks for the responses guys...

Okay, so IF i decide to swap out the engine to a 340 or 360, it'll work with my the manual 4 speed that's in there right? Probably need a better cluth, any recommendations?
Click to expand...

You will probably use the bell housing and flywheel off the 273 engine there may be balancing issues depending on the engine you use and the year of it.

The 273 is internally balanced, some 340 and I think all 360 factory motors are externally balanced. So if you are rebuilding an engine you will have to internally balance it. You should probably upgrade the clutch from the stock9.5" to 10"-10-1/4" performance clutch.
 
Like Perfacar mentions, et is in the chassis, MPH is the HP.

It takes about 275 rear wheel HP to go 12.80/104 at 3300#. That's going to take around 325-350hp at the crank depending on drivertrain efficiency. It's a bunch easier to get that from a 340 or 360 than a 273 and it's a SIMPLE build with nothing special. 360, kb 107's, Comp XE268H, stamped rockers, stock 1.88 or 2.02's, LD340/Air Gap, 750DP, headers and decent ignition... DONE, 350ish HP.
 
Shane65 said:
Hello everyone,

I'm new to the forum, and i'm in the process of fixing up a 65 barracuda. Seems like most people swap in a 340 or 360, but I'm curious what I can do with the 273, if it's worth it...

My goal is to have a fast street car that I occasionally take to the track. High 12's would be plenty quick for me, I'm not trying to break any records. Is this possible in an all motor 273?

Anyone have links to 273 builds, or videos?
Click to expand...

I'd say it depends what you want to spend and/or how important it is for you to do 12's. Also, is it absolutely necessary to be all motor? How about a slightly warmed-over 360 and this....(there's a carburetor in that box)

_800px_P5030801.JPG


http://www.paxtonauto.com/product.php?id=127
 
I raced a 318 and after thr first season put 360 heads with 2.02 valves in place of the stock 1.88 intakes. The bigger combustion chamber lowered the compression, the bigger intake port dropped the intake velosity. Result is that I had a hard time launching and ended up after a season of playing with a car that ran 1 mph faster and .05 quicker than with the 318 heads. It had a 4.30 surgrip. What I am trying to say is 360 heads on a 273 is not a good idea for a street driven car especially with street gears.
 
Many times it is the combination that works. I've run 72 340/360 heads on a 273. It ran very well. Never had quarter mile times. I ran 1.88 intakes and cleaned up bowls. They were milled .040 to get chambers to 64.7cc with 10.5 pistons. I ran a used 340 cam set to 114 centerline with a stock 71 340 intake and Carb. Absolutely no comparison in power to the 273 heads and 600 Holley. I ran a 4 speed and 3.23 gears plus 4.10's for racing and 2.76's for trips. You are correct that it was too much for the street, even though I ran it for years. Only poor gas made me pull that engine. 360 heads can run very well with the right combination and tuning. My 66 has 66 273 heads to prove your point.
 
My 273 Commando build on my '66 Barracuda Formula S:
- port & polished heads
- dual exhaust with h-pipe - V-Force mufflers, 2 1/2" pipes
- 600cfm Holley Double Pumper
- Lunati Cam .515 / .525
- stock ex. manifolds
- Edelbrock RPM intake
- 4.10 rear
- 8 3/4 sure grip 489 case
- running premium gas without additives!
- 205 / 70 / 14 BFG's all the way around
- factory 4 speed manual trans.
Never had it on the track but compared to other cars I've had it feels like a mid - high 13 car. I tach 3000 @ 50mph but I suck at racing a stick so someone with some skill like a friend of mine makes her feel like a flat 13 sec. car....Have over 10,000miles on this set up!...
I want headers but there's nothing out there for the 4 speed & power steering combo.
 
I like the idea of building the smaller engines, I'm finishing up a 318 for my EL5 Dart that should be pretty fun, hopefully around 350 hp. But I'm not hoping for 12's, I just want to have fun and still be able to drive it everyday.

If you really have to get in the 12's to have fun, then you should probably look at a bigger engine. The 273 would probably get you to the mid 13's, maybe even low 13's, without a ton of trouble. But 12's are a different story. Not saying you couldn't do it, I'm sure it can and has been done. But at that level it would cost more and probably wouldn't be as fun (or easy) to drive on the street. Just depends on what you want.

Now, where are you in CA? I can make you a heck of deal on a '74 360 (its in the classifieds)... :D
 
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