carb-header upgrades

[bamastang]

I was at the MCA 30th show this past weekend and had a long talk with Tom at Pony Carbs. He questioned the advisability of upgrading to a 2bbl carb and headers. He also said that those that did have all sorts of driveability problems - normal driving was terrible - only good when at full speed. For those that have done this conversion, please let me know about driveability problems.

I need to understand how this conversion works. The only modification to the log is enlarging the hole 1/4 inch? Is this true? Does this work well since the same size tubes going into the engine are still there? Please explain the physics. Also, if the same size manifold tubes are there how does increasing the size of the outflow pipes help? Again, I'm having trouble with the physics.

I'm looking at purchasing an 80's 200 head to modify for my 200 engine. I have a 66 convertible with a 68 200 inline engine. Should I get a 250 head or stay with the 200? Are there any intake manifolds that I can get that work if I have a machine shop take off the log? How difficult is this conversion?

Thanks for all your help. I'd like to boost my engines performance to 190 or so horse power and have been told conflicting things from different people. I'd like to use an autolite 2100 and an tuned exhaust. Those that have modified your engines, please let me know how you did it and if it works well for daily driving?
Thanks.

 

[Bobscoupe]

Frank,

The guy from Pony carbs is wrong about two barrel carbs on the Ford 200 in-line 6 cylinder engine.

The good news:
There are many ways to upgrade to a two barrel. Direct mounting to the log style intake with a fabricated 1/2 aluminum plate is the best. This method is described in detail in the Falcon Six Performance Handbook which is a must buy if you want to improve performance on your 200.

You can also mount a two barrel via a 2 inot 1 adaptor. Several companies make them Clifford performance, Trans-Dapt, and Stovebolt engines are a few.

In addition to there being sevral ways to adapt there are several carbs to choose from. Autolite two barrels are a great choice as well as Holleys and Webers. Several of us are running Holley/Weber 5200's that we get rebuilt from Stovebolt engines.

I have a H/W 5200 mounted with a Clifford adaptor that I love. Combined with a DuraSpark II distributor and a MSD 6 control box it runs just as smooth as my wife's 2005 Toyota. I'm not making 190 horses but it is a big improvment over the stock setup.

The bad news:
You cannot make significant improvements in this engine without modifing the stock head. However porting and polishing the head, three angle valve job with a back cut on the intakes and milling to achieve desired compression ratio will make a huge difference.

The best cast iron head is the post 78. The 200 and the 250 heads are the same animal. The later model heads had larger combustion chambers to lower compression for lower octane fuels and to pass EPA requirements. They also have larger valves, hardened valve seats (for unleaded fuels) and the largest intake volume.

If you haven't checked out classicinlines.com for performance parts you probably want to start there. Mike (the owner) is developing an aluminum head that has great potential. It has not been release for sale yet but the prototype is in testing. He also can provide you with all the performance goodies you need.

Mustang Geezer has a nice web site with plenty of how-tos you will want to check out. Do a search for his user name and click on his web site under his profile.

Welcome to the board.

 

[nachoman]

It all depends upon what you are trying to do. Think of it this way: the stock 200 intake and exhaust is very restrictive. larger passages and wider bends mean less restriciton and less power that gets robbed from the engine. You have to slow down more to take a sharper curve in your car, and likewise exhaust is slowed more through the tight bends in the stock manifold. A header lets the exhaust out faster.

I personally don't see how much a 2 barrel into 1 adaptor will do for power, since the restriction is in the size of the intake more than the CFM of the carb. Others here will disagree. A larger 1 barrel will help if the carb spacer is opened larger.

My logic says neither exhaust or carb improvements will do much without a different camshaft.

hope this helps,
kevin

 

[Anonymous]

I too was hesitant to make the leap to a 2 bbl years ago. Then I looked at the carb size on my 74 cu in Harley. Technologically speaking, that carb was long in the tooth when they put it on in 1958. It was a larger carburetor than what was on the Mustang which had 200 cu inches to feed. Granted there are some additional physics of a 2 cyl vs a 6 cyl engine. But I was having problems with the Mustang's 1 bbl carb after a rebuild, and I figured I would try out the Weber 32/36. Seat of the pants says that the engine is making a tad more HP and the throttle delivers more snap than it used to. Overall, I would say the drivability is improved. Making a blanket assumption that the 1 bbl carb openning and the log head is limiting all of the performance is not valid. The head is not the limiting factor until you get to the higher flow ranges. Most of your driving is spent well below those operating ranges. A carburetor is going to operate in some ranges better than it will in other ranges. In some operating regions, the carb may be the limiting factor. It may not necessarily be sub-standard on air flow capacity, but rather it may not deliver a consistent fuel mixture. Properly tuned, a 2 bbl should probably have a broader operating range with fewer/smaller regions of compromised performance. Now that I think of it, why didn't the manufacturers continue just running a 1 bbl on the small 4 cyl engine Pinto's. I suspect the 2 bbl's gave better performance. Lord knows if it did not have some tangible benefit, the bean counters would have preferred installing a cheaper 1 bbl that could have satisfied the flow capacity requirements.
Doug