Manifold change on my '66 7 Litre.

[bsprowl]

I need some opinions on my ’66 Galaxie 7 Litre concerning a carb manifold change.  Right now I have a 0.030 over 428 with a Side Winder using carbs that vary from the original 450 CFM Autolite to a 780 Cfm Holly. The engine has a small cam, factory long tube headers, wide ratio top loader, 3.25 gears.  I use it mostly for "spirited" cruising with an occasional trip down a 1/4 mile track. 

I'm considering two changes:  1) 3X2s using a Holley 4412 (500 CFM) as the center carb and two 6425s (600 CFM) as the end carbs. Converting the total flow of these into the more common rating using the 4 BBL test vacuum of 1.5 vice the 2 BBLs 3.0 vacuum there will be a total of 1190 CFM.  Or 2) a 2X4 Ford intake with a set of BJ/BK carbs.

I believe my power output is limited by the exhaust system.  The long tube factory manifold and 2-1/2inch exhaust system is too restrictive to make much more power, even at the track when I take the header pipes off. 

Still I want the most power especially at low to medium RPMS in street driving. 

I think either option will increase the “oh wow” about the same when the hood is open.  I’d always want to run the 3x2 setup but 2x4s would be nice also especially if I dropped the money for a medium riser intake. 

Your thoughts, please. 

[jayb]

I'd recommend using the 2X4 setup and the medium riser intake.  It will make a lot more power than the 3X2 setup, even with the bigger carbs.  That 3X2 manifold is a low riser, and it can make good power, but it needs a good porting job to really perform.  The MR 2X4 intake is a bolt on and go setup, especially with the BJ/BK carbs.

Also Bob, I'll wager that the cam in that engine is more of a horsepower limiter than the headers.  Those factory cast iron headers really work...

[bsprowl]

I was planning and having Joe C, work over the 3X2 intake.

Bob

[Ford428CJ]

Hey Bob,

  Dont want to burst  your bubble.... Even with a ported out 3X2 intake still wont be a match to a Tunnel Wedge intake. So I guess you have to decide on what you want.... 3X2 have a cool factor but a Tunnel Wedge really looks bitch'n and one hell of a performer! JMHO   

[Wreckless Warren]

Are you contemplating a rear gear change Bob? As Jay said, the cam may be your weak link right now, but you don't want to hurt you low end torque needed with that gear (good thing you have the wide ratio box). You would probably feel a good change by going to a 3.50 - 3.70 gear by it's self. Then if you needed more cam you would have allot of options.  I don't think more carburation is going to help you much off the line with your current setup. ww

[Ford428CJ]

Are you contemplating a rear gear change Bob? As Jay said, the cam may be your weak link right now, but you don't want to hurt you low end torque needed with that gear (good thing you have the wide ratio box). You would probably feel a good change by going to a 3.50 - 3.70 gear by it's self. Then if you needed more cam you would have allot of options.  I don't think more carburation is going to help you much off the line with your current setup. ww

True statement.....

[jayb]

I was planning and having Joe C, work over the 3X2 intake.

Bob

I saw some dyno numbers for a guy who made really good power, well over 500 HP, with the 3X2 intake after Joe ported it.  I think it was on Barry's dyno.  I think I'd still go with the MR dual plane intake and the 2X4s, though; they are easy and they really work.

[bsprowl]

I'm not after max power as it really needs better heads than the ported (by me) C6AF-Rs is now has.  My local track doesn't like convertibles without roll bars so I don't plan to up the power much.  I just can't seemed to make up my mind between the 3x2s and the 2x4s.

(I've got CJ heads, one of Jay's adapters on order, a bigger cam, 4.30 gears and even a 427 with a 428 crank but those aren't what I plan to use for this car.)

Thanks for your input.

Bob

[BH107]

Personally I would go with the 2x4, more power, easy to work with, and look awesome. I love a 6v setup too, but they just don't look right to me in anything built past 63. The dual quad just looks right since they did come in the R codes.

[jayb]

I'm not after max power as it really needs better heads than the ported (by me) C6AF-Rs is now has.  My local track doesn't like convertibles without roll bars so I don't plan to up the power much.  I just can't seemed to make up my mind between the 3x2s and the 2x4s.

Well Bob, for what its worth I ran a 3X2 setup on the 428CJ in my Shelby convertible for most of the 80s and early 90s, and I really liked it.  It had a nitrous system installed to make more power, but as far as driveability and appearance it was pretty hard to beat...

[Joe-jdc]

Having read all these threads, and having owned and driven just about every combination of FE with 6V, 8V, and 4V set-ups, I personally would gasket match a RPM, and remove the Logos off so that it would be non-descript, and enjoy it.  Now if you want a show car that is only driven to the car shows, then either of the multiple carb set ups would be cool.  It is a bear to get the 6V to flow enough air to be competetive, but it can be ported to work well.  JMO, but a single 4V for the street is way more simple in the long run, and much more fun.   Joe-JDC.