Thread: A 4 Barrel Carb on a Straight 6

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I have a '69 Mustang with a straight 6. Would it be worth putting a 4 barrel carb in it to boost the power? Would it make a significant difference without destroying the engine? Also, does 'octaine boost' fluid actually work and is it harmful to the engine?

Thanks.

Originally posted by SFU
I have a '69 Mustang with a straight 6. Would it be worth putting a 4 barrel carb in it to boost the power? Would it make a significant difference without destroying the engine? Also, does 'octaine boost' fluid actually work and is it harmful to the engine?

Thanks.

the 4 barrel on the stock 6 would be a little overkill, no a lot of overkill. rpms destroy motors, not carb. it will help some under certain situations. it probably wont help you, but try it, it wont hurt anything.

I'd have to go along with techinspector although I did put a 390 holly 4 barrel on my 300 CI ford engine without any problems. If you do indeed have the small 200 you might be better off with a 2 barrel adapter.

My Falcon has a rebuilt Holley, it looks like a 1bbl but I actully think it's a 2bbl because theres a carb in summit that looks much like it and it's a 2bbl, I want to get the # off it to be shure of what it is, it seems like it's too much for the motor ( 200 6 ) but I havn't tuned it. I was thinking of putting a Holley 2bbl on the '51 Chevy which would include a 58.00 carb adapter from Clifford and 219.00 for a new 500 CFM holley 2bbl w/ manual choke or 158.99 for the same carb except rebuilt for Jegs, 350 CFM model is 239.00 for new and it's not offered rebuilt, would this be good for the 235 6cyl? Would I need new throttle linkage? I got all winter to contenplate the idea and work on the car when time allowes me too like days off.

I have been running a small Holley 4bbl on my 77 Toyota Landcruiser with a 258cid 6 cyl for 15 years. Once I got the jetting correct, I noticed an increase in performance and 3 mpg increase in mileage. It originally came with a 2bbl wcarb that had a vacuum operated 2nd barrel that was constantly opening and closing at 55mph, it just about made me carsick with the surging.
I was able to buy an aftermarket manifold to fit the 4 barrel carb.
Jerry...

Why even bother with a 4 barrel? wouldnt it be easier to just get a good 2 barrel? you have to consider, your only moving 200 CI. It would probably be more cost efficent to put a small V8/Large V6 performace carb on that motor.

It is more efficient to run with a 4 bbl then a 2 bbl carb. With a 2bbl the 2 barrels of the carb have to be sized large enough to run at WOT, which means lost low RPM grunt and poor economy at lower speeds. With a 4 bbl the 2 primary butterflys are typically smaller then the butterflies in a 2bbl carb which means better low end response and better economy. Under WOT conditions the secondaries open after the primaries which inturn helps make more top end power then the 2 bbl.
As for the intake manifold, I have made intake manifolds for inline engines from tubing and have seen dragsters with inline engines running handmade manifolds that seemingly work fine.

http://www.cantonracingproducts.com/.../adapters.html check this site out, seems like if you bought the 2bbl carb adapter for a 200 6 from clifford that adapts a Holley 2bbl then used 1 of these holley 2bbl to holley 4bbl adapter would save the effort of having to fabricate a manifold or manifold adapter if it is possible, although it does seem like a 2bbl is enough for a 200 6.

Originally posted by lt1s10
the 4 barrel on the stock 6 would be a little overkill, no a lot of overkill. rpms destroy motors, not carb. it will help some under certain situations. it probably wont help you, but try it, it wont hurt anything.

i ment to say, try the octaine boost in the above post, not the 4 barrel carb. but to get back to the carb. i doubt that you can buy a 4 barrel carb. that the primaries are smaller than the carb on that 200 motor, but i agree that the right 4 barrel is more efficient on a bigger motors.

Originally posted by mrmustang
Matt,

I really think you missed the boat on this one.....I sell Canton products such as this, however, they are meant for the dirt and asphault modified guys who run in both 2V and 4V classes.....The adapter allows the use of the 4V manifold to bolt the 2V carb to in order to make it class legal....it does not, I REPEAT, does not allow the use of the 4V on a 2V manifold!!!!!!!!!!!!!!!!


Bill S.

Thanks mrmustang for correcting me, I knew it was a longshot posting that, I was just searching the net seeing if such an adapter exzisted and I thought that was what I was looking for and I did post " if it is possible " because I was unshure if such contraption could work but I guess not. Thanks again

Hey streets, lets do some math here. 6X2 barrel @ 300CFM flow=1800 CFM. Now WHEN would you need 1800cfm on a 200I6?

I agree. 4bbl carbuerator is too much for an inline 6.

See if you can get yourself a nice upgraded performance 2bbl carbuerator from either Holley or Edelbrock. I have a Edelbrock performer series 4bbl 600cfm and its great. With normall cleaning and rebuilding it has been useful.

Now if you have a 1bbl carb which is a very good chance it might have, being they put 2bbls stock on V8s back in the day, then upgrade to a 2