1967 273 V8 change to 6-pack carbs

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gljplc

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Guys,

My 1967 Barracuda has the stock 273 V8 and I want to change it to a Mopar
small block 6-pack carb setup. I want a street only cruiser.
All of the reference books indicate that the 6-pack intake will simply bolt on with no changes.
Has anyone tried this ??

I need any advice on this.
Thanks,
GLJPLS
 
im sure a lot of people havent tried it on 273's but it should fit fine, its a LA intake. Only problem i can think of is you might need 318 or 360 heads but i doubt it.
 
It will bolt right on , but if you have air conditioning it will get in the way. It's an awful lot of carb for a 273 though, but it will look cool!
 
gljplc said:
Guys,

My 1967 Barracuda has the stock 273 V8 and I want to change it to a Mopar
small block 6-pack carb setup. I want a street only cruiser.
All of the reference books indicate that the 6-pack intake will simply bolt on with no changes.
Has anyone tried this ??

I need any advice on this.
Thanks,
GLJPLS
Click to expand...

Go for it....
360.jpg
 
I know early 273s had a different angle for the intake flange and/or bolts, and wont interchange. I dont know what year the break is, '67 may be ok. But, I would not bother. A 6bbl works on engine load, like a vaccum secondary carb. It will run great on the center, but the outboards will cause havoc if you ever try to use them. You'll get better power from the stock single 400cfm or so 4 bbl. In addition, the port size of the intake is MUCH larger than a std 273/318 port. That's also not helping anything. There were 273/318 2 4bbl intakes at one point. I'd say for a cruise night deal, I'd run one of those with 2 small (500cfm?) edelbrocks, on a progressive linkage, like the Hemis used.
 
IIRC, offically, it 320 on the ceter carb, 500 on the outboards..But, 2bbl are flowed in a different manner, so the comparison may be a little off. Personally, It's way too much for a 273. But that's just an opinion. Maybe leave the secondaries (outboards) closed?
 
moper said:
IIRC, offically, it 320 on the ceter carb, 500 on the outboards..But, 2bbl are flowed in a different manner, so the comparison may be a little off. Personally, It's way too much for a 273. But that's just an opinion. Maybe leave the secondaries (outboards) closed?
Click to expand...

You'll be waaaaay over carbed. But it looks soooo friggen cool it might be worth an engine upgrade :drunken:
 
I think 65 was the only year with the odd ball intake bolts. However the ports on the 6bbl intake will be bigger then the ports on the heads. The 6bbl set up flows about the same as a 980cfm 4bbl.
 
Yes, the rating is a little intimidating. But, you need to clarify a little Adam. The 6bbls, like most basic holleys and edelbrocks, are flow rated by testing dry. That means they are flowed with nothing to simulate fuel, which would allow less air thru because of the air the fuel wouldl displace in the carb throat. the HP series, Avengers, Demons, and other higher end carbs, are wet flowed. Technically, this means a "680 cfm" Avenger, flows about the same amount of air as a 700 old school holley. Wet flowing is much more accurate, but it's much easier to overcarb that way. In any case, there's too much for a 273..At wide open throttle, the outboards would simply crack open, and that would be it, they'd never get full open..ever. It's a lot of money to stare at.
 
I'm not a %100 on this, but 64 was the first year and had the odd ball angle. I do not know about 65 or newer 273's for sure.
The 273 and the 318 share port size. The 340 and the 360 share the larger port size.
You could use it with the smaller ports, but would port match it for better results.
 
Putting a 6pack on the 273 is a waste of time unless its a highly modified motor made for the drags,and even then it would be a 4 barrel carb or dual 500cfm,s on a tunnel ram turning 8-9 grand.If the motor is running at 100%V.E. at 6000rpm,it only takes in 475cfm,so take off 15% for the average street motor tuned to the nines.It would look neat if you installed it on 340/360 heads and only ran the center carb,as the middle carb would be more than enough for your motor by its self.The ports on the 273 heads are to small for that intake and would do more damage than good.Find a 340 or 360 and install it on that and have a blast with it.Mrmopartech
 
I have a stock 273 in my 67 Cuda, with a 509 solid purple shaft cam
with a single 495 cfm Holley.
my motor can't handle much more than that, and my last set of plugs didn't last long either.
if you use that set-up with that much fuel it may wash out the rings down the road.
 
Some 318 4 barrel heads had the large ports too. Some 360 2 barrels had small port heads .

I say put it on there if you have one. It will drive fine and look way cool. My 67 273 with .528 solid DC cam with holley 650 double pump , stock low comp pistons, 360 intake , ect ran great to about 7000 rpm. Yeah, I know, it was a waist of parts, engine rpm because the stock 2bbl heads probably didn't flow more than a fart past 5000 rpm, would have been alot better with a 340-360 with head work and all but I was 17 and learning. I tried to put my 3x2 on it but when it wouldn't clear the A/C, I sold the setup for 200 bucks, ouch!

With all that stuff in my 273, with 125 shot of nitrous, I barely, and do mean barely, beat my brothers stock 440 in his B-body. But when we pulled into a parking lot together people seemed to be more interested in my overcammed small block 67 Dart GT than his absolutely beautiful 66 Sattelite. (yes, we put the 440 in his Sattelite, original 383 car).
 
64-65 273's had the angled manifold bolts similar to the magnums. That was changed in 66 to the standard angle found today. As far as a six pac, way too overkill fo that motor. Total cfm at WOT at around 1150 plus. There will be an intake head mismatch which could result in a massive vacume leak. the 273 haeds flow an average of about 151 cfm at .450. Go with the duel 4 setup. You can still get the manifold that fits the 273 heads (smaller ports) from Offy. Some of the D/darts were run with the duel 4's
 
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