HUGE Carb

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Hey Guys, I just recieved a Holley 600 CFM 4 barrel for my birthday and I was wondering if i could use it on my 250 powered 69 mustang? It was sitting around my cousins garage and has never been used. Setting aside the challenge of getting an adapter plate (I can do the machine work) will the carb work? Or is it just too much? I have some radical ideas for the motor in the future (not turbo or anything but horsepower IS a priority) so the air/fuel is going to be used. I'm guessing hood clearance will be a problem? Thanks for all the help!
 
8)

I have no idea how you would modify a log head for a 4bbl. There are several guys running 4bbl carbs on the Aussie/Argie heads.

I dont think a 600 would be too big for a 250 cid engine but I'm thinking it will need rejetted if you were able to attach it somehow.
 
Ya thats what I was thinkin, so it wouldnt just be TOO much carb? Anyone else's opinion? In my mind the large carb would move the power band up in the RPM's and just lose a little in the lower RPM's. Does this sound right to anyone else?

Also, would you suspect any hood clearance problems?
 
Use the 1977 on flat or hex top log head from a 3.3 or 4.1, and perform the Falcon Six handbooks mod of direct mounting a 2-bbl adaptor.

Such as Was111 or MustangGeezers.


The add the aftermarket 2-bbl to 4bbl adpator up side down. Basically, the carb has to have some major alterations


1) to clear the rocker cover

2) to allow the throttle to be turned,

3) and allow the second float bowl to clear the rocker cover.


You can do it if you put your brain into it!
 
well I would try to mount it in a normal front to back fashion and use a early style pull rod throttle arm so that you can just hook on the ball stud and go (how I am doing my 5200 in a couple weeks)
 
I feel the 600 is way too big a carb, you would be better using a 390 cfm carb. Just my opinion. William
 
Bill, the two primary barrels are fairly small and will normally be the only ones working. The secondaries will never open past the engine load requirement so if the engine only needs 400 cfm, it only gets 400 cfm. That will require some tuning to make sure they don't open too fast or too far at a given load.
 
8)

Wont running a 4bbl to 2bbl adapter be incredibly restrictive on the 4bbl? 4bbl?

Will it even operate properly to the point that the secondaries will open up?

It seems to me that assuming everything works properly that the engine will onl;y draw as much air as it can use and if the carb is rejetted for proper air fuel ratio it should run fine. May bog a bit in the low end but one over about 1500rpms it should run fine.
 
Since the secondarys won't come into use you would in reality be installing a rather large, ungainly, two-barrel. It would probably run fine once properly tuned.
Joe
 
I would consider making an adapter and plugging off half of the carb. You could have a progressive 2BRL for less than holley sells them for. Just make sure it looks functional. It just would not look right with half of the carb hanging over the edge. It is something I always wanted to do with my Pinto. Just for the visual impact. Life is just too short to not have a sence of humor!!! :lol:
 
Stubby":1nd0rroc said:
I would consider making an adapter and plugging off half of the carb. You could have a progressive 2BRL for less than holley sells them for. Just make sure it looks functional. It just would not look right with half of the carb hanging over the edge. It is something I always wanted to do with my Pinto. Just for the visual impact. Life is just too short to not have a sence of humor!!! :lol:
Click to expand...

I was thinking about gluing two more Autolites to the top of my intake manifold. No drilling, milling, plumbing or tuning needed! I might bolt another muffler tip below the rear bumper too. :lol:

Seriously, though... I think the 4bbl is a great idea. A progressive 2bbl would be better given the fact that there's not enough area on the intake to handle all 4bbls, but work with what ya got! At least this way you have a progressive setup. Later on, when you are doing more radical stuff to the engine, you can build a killer intake and really take advantage of the carb.
 
Doesnt anyone make a fourbarrel intake for these engines? I am sure that you could fab a sheetmetal intake after all the log works well. Sounds like a good Idea to me.
Good Luck
Steve
 
Jack, you are right in that a holley carb will flow only as much as it needs, depending on the secondary spring in the vacuum secondary area.
My personal feeling that to try to put a 4 barrel carburetor on a log manifold is totaly out of the question.

If you had an aussie head or an argie head which would have space to house a 4bbl carb a 390 cfm would suffice.

Even using a 2barrel carb you have toshorten the pcv tube to clear the valve cover.

***note**I will post a separate article how to remove the pcv tube from the holley & shorten the tube then to press back into the throttle body.

Don't take a hack saw to shorten the tube for clearance, there is a way to remove the pcv tube with no damage to the tube, shorten it and then press it back into the throttle base.

Trust me. William
 
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