Howdy - first time in here, first time Mopar owner.

I have a '73 /6 auto in a Swinger, when purchased it had a Clifford header and a Clifford intake with a Holley carb. I THINK the carb is a 7448, does that sound right? Anyway, it seems in very bad condition, I was wondering which Holley do ya'll think should be on the car? It will be used on the street, not the strip. Seems many favor the Carter, I reckon I could get an adaptor from Clifford, the one I have is for Holley carb only.
The kick down linkage doesn't seem to work, either.

Any suggestions would be appreciated!

Thanks

Holly 390cfm carb, the only way i'd go what else is done to the engine, was the cam changed or anything else?

Justin

7008 would be a good start...390 cfm, Vacuum secondaries, a few people have run these with good success on stock motors, I'm currently tinkering with one on my motor which is a smidge hotter than stock....

7448 would be a Holley 2300, 350 cfm 2 barrel....a fair choice when up grading from a super six or if you got a 4 barrel manifold with a 2 barrel adaptor...


With all carbs, you'll have to run it, check your plugs and vacuum gauge and make jetting and spring adjustments until it's all dialed in...

-D.Idiot

I'm trying to get in touch with the owner who did the mods - it wasn't the guy who I bought it from. If it does have a cam, it is a mild one. It will idle smoothly @ 600 RPMs, when the carb isn't acting up. I wouldn't mind shaving the head a bit and putting in a mild cam, but nothing too radical. I may just get a rebuilt exchange carb, so it sounds like the 7008 (390cfm) might be the way to go. The header now goes into a stock-looking and sounding exhaust system, which I will change also, but gotta get these carb problems solved first.

Thanks.

If you plan to run a four-barrel, I advise that you forget the holley rubbish and run a Carter. Has anyone here tried a 500cfm AFB on a /6? If you have, please speak up, positive or negative. I'm running a 400 cfm AFB, which is not readily available, and it runs so much better than the 390 holley did, you would not believe. Since the primaries on the 500 are still relatively small, and secondary air flow is regulated by an air door, I would think that the 500 AFB would be the best all around street/strip carb for the /6.

Kermit, see related posts, ad nauseum.

"DW"

_________________

If it ain't broke, fix it!

Take off the air cleaner, holley writes carb model #'s on the air horn.

Yeah, it's a 7448, i just had to clean off the spot.....messy. Gonna look at a replacement carb today, wanted to know the actual model numbers of the carbs. First I will call Clifford and ask about the intake and adaptors available...I didn't realize if I took off the 2 bbl adaptor I could run a 4 bbl...I'll check that with them, don't know how old these manifolds are, but the car only has 48K (verified) miles.

The Holley 2300 two bbl in the 350 cfm size works pretty good on a mild SL6.
These carbs are basically 1/2 of a Holley 4 bbl so they are easy to rebuild & tune.
I have used these carbs over the years and found that power valve tuning was the biggest issue / need with getting them to work right on a Slant.
DD

Interestingly, Clifford just told me that their manifold with the 225 /6 needs a minimum of 380 cfm. I have 350 cfm now. He said those manifolds all need an adaptor, that no carb would just mount on direct. He also said they sell a 4bbl adaptor, $65, recommends a 480 cfm 4bbl, said you could go 500 cfm only on a 2bbl.

Correction: He said max of 465 cfm for the 4bbl.

So this guy sez 480 is perfect, but 500 "no way"? That's 20 cfm difference. Sounds like he's FOS to me, but hey, whaddo I know?

"DW"

Follow up: That's STILL only 35cfm difference. Does he give any reasoning as to why he says this?

P. S. - Two barrels are measured at a different vacuum drop than four barrels...

_________________

If it ain't broke, fix it!

He may well be FOS, I'm not that aquainted with these set-ups. If you calculate the theoretical cfm;

Engine size (CID) x maximum RPM / 3456 = CFM
CFM @ 100% volumetric efficiency

(Example: 350 CID x 6000 RPM = 2,100,000 / 3456 = 608 CFM)

Approximately 608 CFM would be required for this engine. However, most Street engines are capable of achieving only about 80% VE; a modified street engine with ported heads, headers, intake and carburetor can achieve about 85% VE; a fully modified race engine can achieve 95% or greater VE. The CFM number arrived at with this formula must be factored by this percentage. (from the Holley web-site)

and use -what - 5,000 rpm? - then you don't come anywhere near the 500 cfm. The guy at Clifford doesn't sell carbs, so I don't really know where he's coming from. He did say "max" cfm, not the perfect cfm.

Since I have a little more money than brains, I am going with the 390 cfm 4-bbl, getting a new one, just ordered the adaptor plate from Clifford.
There's no air up here (6,600 ft.) anyway!

Been there, done that. See the pics of my Carter equipped car in the slixer's gallery section. Ask CharlieS how my old 390 holley's doing. He's the new owner and I hope he is happy and I hope you will be, too!

Most of our air here seems to be in the form of humidity, so maybe my brain's oxygen-starved, too

By the way, I know that 500CFM is overkill on most any 225CI engine, but since it is the smallest rated Carter available new, I propose that it might actually work well since the rear air door would basically regulate the overall flow. If I had a 500 Carter laying around, I would try it on my /6 in place of the 400CFM unit just to do a little research.

"DW"

_________________

If it ain't broke, fix it!

Yeah, you can adjust them to stay out of that secondary until real late, and control the accel. pump, you should be OK...learn to 'squeeze' instead of 'mash'....

Why do you think I would need to stay out of the secondary? The air door (a second set of throttle butterflies, really) is only going to open up according to engine demand. The pump circuit's identical to the one on my 400 AFB.

"DW"

_________________

If it ain't broke, fix it!