Converting VV top end to 4-barrel

[johnunit]

As much as I've said I wanna keep it original-looking, I'm getting discouraged about my ability and willingness to rebuild the 7200VV carb, especially after finding out I need to drop another 50+ bucks on a special tool set. Logical second option: Convert it to a 4Barrel top end.

The simplest and most tried-and-true method seems to be P72Ford's combo on The Red Box:

Edelbrock 3783 EGR intake, 8053 EGR plate, 1406 carburetor, and Lokar SS throttle cable

Getting the carb and intake used, that's probably $400ish all in if I'm patient, which is something that could be done in the reasonably near future.

The problem is, P72ford seems underwhelmed by the results, even with 3.73 gears (which I'd also be looking at) and a full exhaust system. I know part of the issue is a wonky tranny, but it still makes me hesitate. He reports only a couple MPG loss going from the puny Variable Venturi to the eddie 4barrel, but his original mileage (17mpg highway) is a good bit short of what I'm getting.


The other option I'm thinking of is a smallish (590CFM?) Holley with whatever other intake people here would recommend.

I'm open to any suggestions, but my main questions are:

1. Just how quickly do people think the VV carb would be come a limiting factor in performance? I realize that's hard to quantify, but if I went to a combo like GT40 heads, Explorer cam, BBK swap headers, and a 2.5 inch catted dual setup, would it be absolutely killing my power at that point? Would it make those mods useless or just reduce the effectiveness? I'd like to keep the carb if I could just for a bit of sleeper effect (when the rest of the engine is pumped up) and for originality, but if it's an absolute non-starter, I might as well keep it in the basement and put a real carb on it.

2. What actually has to be fabricated and tweaked for me to run the Edelbrock setup above and lokar throttle bracketry? This would be keeping the EGR and everything else as original as possible. Is there anything else I'd need other than gaskets?

3. What other Intake and carb combos would be suitable keeping in mind the (short term) future mods of :
gt40 heads, full exhaust with headers, 3.55 or 3.73 gears, HO valvebody and a few other little tranny things
and would those intake/carb combos need something other than the above Lokar unit to work with the AOD


4. Am I right in thinking that a 4bbl intake with 2bbl adapter under the stock carb will do dick all, or is that maybe a worthwhile intermediate step?


Any other issues people can think of like accessories not fitting, hood clearance, etc. I'd be interested to hear.

[1987cp]

Do it!

I actually scored an old Carter 9500 (same as a 500cfm Edelbrock AFB) on eBay for about $85 shipped, and this particular one was already rebuilt, just needed a good once-over to clean out cobwebs, recenter the throttle blades, install the right throttle hookup, swap to electric choke, etc. The smaller carb is often a good match for a stock engine that may have crap heads and exhaust, etc.

When TOTCG installed the EDL-1406 carb on my car's original 351, the Performer 2181 manifold had enough throttle bracket mounting holes that he was able to bolt the original throttle bracket up without any gymnastics. It would have required a small degree of creativity if he had used a carb spacer, but without one, he just bolted the old bracket to the new intake and it was fine.

The TV cable on this car, by the way, is basically identical to the stuff you get from Lokar nowadays, and it too (and you can verify this with him) appears to have bolted to the stock throttle bracket without modification. Consider getting a suitable TV cable corrector to go with it - the Summit Racing one is pretty affordable at about 20 bucks.

[johnunit]

Allright. So with an EGR spacer I might run into throttle cable issues, but with an edelbrock 2181 and 1406 I can run stock throttle bracketry with a bit of bodging and maybe the summit racing TV corrector.


Is there anything I should look for as far as particularly desirable carbs used? Ones that aren't worth my time? Is there anything specific that made you choose the Carter or was it just a good price?


Also, will I have to use a pressure regulator, or would I be able to just re-route the stock line from the stock pump?

I'm guessing I can run the stock air cleaner housing and PCV system too, right?

[torquelover]

The TV cable on this car, by the way, is basically identical to the stuff you get from Lokar nowadays, and it too (and you can verify this with him) appears to have bolted to the stock throttle bracket without modification.

I hear the major difference is the geometry correcting bracket on the throttle arm, and also the preload/return spring on the trans end. Did your Lokar have these items?

johnunit, if you're ditching the VV because it needs service, don't get your hopes up in regards to performance. The motor really needs a better cam, much better heads, and a compression jump in order to just keep up with modern V6 family sedans.

As far as P72ford's impressions, his car's shift programming is all messed up, and until it's corrected, I imagine it would feel like a sloth stuck in mud. Been there, done that.

You running a 2.73 RAR? What RPMs does your AOD upshift into 2nd and 3rd at WOT now?

What made matters worse for me, and also for P72Ford if I remember correctly, is the 2-D-OD valve body. No way to select 1st gear manually and hold it. As such, my old car before the new trans was upshifting well before 3k. Especially frustrating with the 2.73s.

Good luck in whatever you do. Anything you need to know, feel free to PM me.

[johnunit]

Thanks TQ.

I'm shifting somewhere around 3800RPM at WOT into second according to internet calculators. Not sure about 3rd.

I'm not expecting much in the way of improved power, probably barely enough to show on a dyno. It'd be more to make it so that I'm not battling a major restriction points when I do the cam, heads, exhaust, etc. that I'm planning. It'd also be to make it more reliable. I'd love to have a strong-running car with an original-appearing engine, but considering that right now it's no show car, and I'm in the "prime of my life", I might as well have something reliable and powerful now, and tinker with the stock stuff for later.

I have 2.73 gears. Shifts into second at just about 50MPH, so I know that's gotta be one of my first points to change. It's a Canadian civi (or perhaps just fleet?) model though, so the shift pattern is PRNOD1 like a 5.0 panther. I don't know if that means it has the seemingly different police 351 valve body or not though.

[torquelover]

Allright. So with an EGR spacer I might run into throttle cable issues, but with an edelbrock 2181 and 1406 I can run stock throttle bracketry with a bit of bodging and maybe the summit racing TV corrector.


Is there anything I should look for as far as particularly desirable carbs used? Ones that aren't worth my time? Is there anything specific that made you choose the Carter or was it just a good price?


Also, will I have to use a pressure regulator, or would I be able to just re-route the stock line from the stock pump?

I'm guessing I can run the stock air cleaner housing and PCV system too, right?

Are you in an emissions-check area? If not, get the non-EGR items.
I don't know what the Summit or Lokar parts look like, but the Total Performance/SVO one I had bolted right up. That was a long, long time ago. They are gone, and I believe I got the last kit. Shouldn't be hard to make what's currently available work, many have done so here.

The Edelbrock/Carter carb is easy to tune, and has good street manners. If you're looking for power, there are better choices. Go to a parts store where you can actually see the carbs in person, get them in your hands, and take a look. It will be plain as day as to which ones are quality pieces. I went with the 1406 because I was following the Edelbrock Performer 351 recommended parts. I ran out of money before the heads were purchased, so rebuilt E7TEs went in. Times have changed, and there are far better choices now.

Current fuel system should be fine.

My air cleaner did not fit the carb/intake combo without running a spacer. If I remember it correctly, the base was not the right diameter as well. I ran all new PCV components after several years of running without it, so I'm unsure if what you have now will work. It was such a mess under the hood of a stock 351 with VV, I just tore everything out and only put back in what was needed for basic function.

[King_V]

My rough guesstimate with the 2.73 gears, assuming stock-sized tires, is that you're doing around 4400 RPM at 50MPH in first gear.

So either my math is REALLY wonky, or the internet calculators are not all that great.

In any case, it seems that any sort of semi-modern 4-bbl carburetor and more modern intake manifold is going to improve things over the stock stuff. Or, as I've read somewhere, carburetor technology has vastly improved more since the proliferation of EFI than at any point in the heydey of carburetion. So I really think you can't go wrong with a decent 4-bbl and intake selection.

Doesn't the VV's design hearken back to the late 70s? Or did it evolve a lot during the use in the 80s?

[johnunit]

Yeah I'm in an emissions area, and also an area where they'll do anything they can to ding you for "street racing" under a section that essentially means any modified car is designed for racing and not meant for the street. That was actually part of why I was trying to leave the original carb and air cleaner and all that, even if I swapped the cam and heads, was so that if I ever had to pop the hood for a cop they wouldn't see anything untoward.

Sounds like I'd just wait and see as far as air cleaner and PCV and all that, since if I had to go aftermarket it wouldn't cost much.

I know what you mean about the underhood being a mess. I'll admit there's still stuff I'm not 100% sure the use of after almost a year of ownership.

If/when I do this, it'll be while the car is off the road, so it sounds like all I need to dig in is a 351W intake (recommendations? is the edelbrock from the original post a good idea or has something better come along?) and a 1406 Edelbrock or similar plus gaskets. Then I should also budget in a cushion for an air cleaner assembly and throttle bracket.


What about the feedback electronics? Can I basically cap off anything going to the computer from the carb and leave it in it's place for now or will I screw up the timing and whatever else is also run by the computer?

[johnunit]

King V, it shifts a little before 50, maybe 47-48 (hard to remember because I'm changing from an approximate KPH to mph). at 4400RPM I would be going 53MPH, which is well over 80KMH, which I know I don't quite hit in first.

4000 RPM brings me to 48.5 MPH, which considering the nice round RPM number and all sounds about right. The car is still pulling plenty strong when it shifts, so I'd be surprised if it ever spins past 4K.

[1987cp]

The Total Performance TV setup appears to be identical to the Lokar, as I have one of each. The Summit Racing TV correctors are likewise identical to those available from Sonnax or TCI.

The Edelbrock/Carter carb is easy to tune, and has good street manners. If you're looking for power, there are better choices. Go to a parts store where you can actually see the carbs in person, get them in your hands, and take a look. It will be plain as day as to which ones are quality pieces. I went with the 1406 because I was following the Edelbrock Performer 351 recommended parts. I ran out of money before the heads were purchased, so rebuilt E7TEs went in. Times have changed, and there are far better choices now.

This reminds me, if actual power is planned, Mr. Land Yacht has some carb parts that may be coming up for grabs, including (IIRC) a BG carburetor with relatively little run time on it. I really ought to buy that carb from him, but I have zero money and will see little if any benefit with my crap heads and cam.

[johnunit]

Are there any reasons to prefer an edelbrock over a Carter of the same CFM and specification other than it likely being newer?

Something like this plus a rebuild is a lot more "accessible" than a new Edelbrock, and helps me with my wanting to look stock underhood at a glance.

http://toronto.kijiji.ca/c-cars-vehicles-auto-parts-tires-engine-engine-parts-CARTER-AFB-CARBURTOR-4-BARREAL-W0QQAdIdZ182602149

Also, what are the pros and cons of a similar Holley (like below, though I think that's manual choke) compared to an eddy? I know they're more complex to tune and generally touchier, but I'm assuming the tradeoff is better performance potential.

http://toronto.kijiji.ca/c-cars-vehicles-auto-parts-tires-other-parts-accessories-Holley-600-CFM-Performance-Carburetor-Carb-1850-3-Nice-W0QQAdIdZ182188699

[1987cp]

The benefit of an Edelbrock over a Carter is that it can be purchased new, since Carter hasn't made carburetors in quite a number of years. The Edelbrock Performer Series AFB and Carter Performance Series are the exact same carburetors, with the except that the Carter Performance Series could be had in a 400cfm version, which Edelbrock does not offer. To get started tuning an old Carter, buy the corresponding Edelbrock tuning kit.

Holleys are a completely different critter, using power valves instead of metering rods to handle fuel enrichment, and having separate fuel bowls screwed to the fore and aft of the main body rather than the integral fuel bowls of the one-piece AFB design. One benefit of the Holley is the extensive tunability of the power enrichment circuits, and another is the cam actuation of the accelerator pumps that allows more (and more precise) fine-tuning of the accelerator pump. The different Holley pump cams even have different profiles, so you can fine-tune how quickly the squirter is squirted as well as exactly when in the pedal travel it squirts more or less. Neato stuff.

One thing to watch out for with Holleys is that the inexpensive models often have metering plates instead of metering blocks, which if I remember correctly don't even allow for adjustment of primary metering without changing out the whole plate. There are also center hung versus side hung fuel bowls, and of course mechanical versus vacuum secondaries (you'll typically want to avoid mechanical secondaries for a street car) and fun stuff like quick-change vacuum secondary covers so you can change springs on the fly. By contrast, the AFB design uses a velocity-activated "air door" above the actual secondary throttle blades to control air flow through the secondaries in response to demand. The AFB air door is held shut by weights, and is not inherently adjustable, though a refinement called the AVS has a spring-activated air door mechanism that is designed to be adjusted easily.

BG carbs are a modern refinement of the Holley design.

[Lincolnmania]

if you are on a low budget, a motorcraft 2bbl would be cheaper route.
i never bothered with a 4bbl carb on my first box, a 84 cvpi with a 351......when i bought the car the ford dealer had already replaced the vv carb with a motorcraft 2150 carb....... i rebuilt it once and when i had problems with it again i rebuilt the motorcraft 2100 from a 73 cougar.........car had plenty of power and got decent fuel economy

[carasdaddy09]

Through a 3 2bbl intake on and 3 VV's on it. Performace issue solved.

[1987cp]

That would actually be pretty interesting to see! Not sure a typical 6V intake has room for VV carbs, though ....