converting the head to accept a 2bbl carb

P

Positively Ralf

Well-known member
For anyone who has done this, was it worth it? also, what are the costs like?

BTW, I see CI sells converted heads but there are no prices. anyone know how much they cost? I was actually thinking of just removing the head and sending it to CI for a rebuild since I will have it in storage during the winter. Would this be a better route to take over some random machine shop in my area?

thanks for any replies guys!
 
Here's the results of some dyno testing we did this summer.
http://classicinlines.com/DynoSwap.asp

As for CI prices, I'm working on a web page and hope to finish it up TG day or over the coming weekend.

Looks like we'll be doing crate motors too. I looked at some shop space last night, which is right next door to my machine shop, and I've started buying up 200/250 long blocks, when I can find them. :)
 
Howdy Back Ralf:

To answer your question, YEs, it is worth it if you are looking for any level of increased performance! I've upgraded a '65 200 with an 1101 and '68 point distriburtor and also tried a Carter RBS. I've tried funnel adapter with 2100s too. Nothing is as significant as a direct mounted wide base two barrel. I cannot accurately quantify how much better because while the head was off I cleaned and shaped the ports, polished the chambers, milled, installed a port divider, had a three angle seat, back-cut the intake valves and modified the exhaust manifold. Oh, and added a direct mount 2V opening. The two barrel conversion also included a conversion to a Maverick throttle pedal and cable, adapting and rerouting the gas line. That was on a stock '65 200 block. The difference, with an Autolite 1.08 over the 1101 was night and day. Later the head got a clean up and was installed on my current 250 built block along with a DS II and a single outlet header. Since then, it has had several sizes of 2100s, currently a 1.33, and a Holley 500 (#4412).

My truck is a daily driver, with an SROD 4 speed and a 3:1 8" rear. It is not intended to be a race car, but I do enjoy an ocassional bout of spirited driving. Oh, and it also gets good mileage with a 1.08- 16-17 in town, and 21-23 on the highway. Another advantage of the 2V mod is the wide variety of carbs to choose from and the ease of swapping and tuning. Stock hood clearance is another bonus. I've adapted an aluminum Climactic air cleaner system from an 80's LTD with the lid chromed, added a chromed "Powered by Ford" valve cover to ease throttle cable adjsuting, and it looks like something FoMoCo should have done.

So, again, Yes, it is worth it, but the mod will likely provide you with an opportunity to do several upgrades while the head is off- all worth doing. It is hard to pull out the costs related to the 2v mod because other stuff was done at the same time/bill. My total bill for the head work back then, about 8 years ago, was $270. It would be safe to say that the 2V conversion would be about half of that. In today prices, I'm sure it woule be more.

That's my two cents, for what it's worth.

Adios, David
 
8) i agree with mike and david. i put an autolite 2bbl on my 66 falcon, using an adapter, and even though that is not the best way to go, there was an improvement in overall performance, and no change in fuel economy. a direct mount is the best way to go.
 
David
I have also wanted to know what these head mods would cost. So the direct mount 2v mods on your head accounted for roughly $140.00 lets say. Did that include the adapter plate attached to the head so you could just bolt on the 2100? What machine shop did that for you and are they still in business? Did you go to 1.5" exhaust valves? I have a 66 Bronco with a 250 and am looking for a head to rebuild with these mods you have mentioned. Once I have this I planned to just swap the heads for very little down time and a noticeable increase in power. Low to midrange torque is what I am looking to increase. I live at 4200 feet elevation and thinking about a 9:1 compression.The cost for the rebuild/mods only, not head or carb, I had hoped to bring in for about $400.00 more or less. Does this seem reasonable? If anyone else on here has done this recently would like your input as well.
While the head is off I am going to put some thought into a dual pattern cam or the high lift rockers from CI. If I am feeling up to it I might do both however if the bottom end looks questionable I would just go with the rockers.
I have really enjoyed your book and fordsix.com is invaluable. Ford six guys are really fortunate to have these resources.
David
 
Howdy Back David:

We made an aluminum adapter from scrap. I wasn't aware of any commercial adapters at that time. I think Mike carries an adapter at CI. Most any competent machine shop could do the work required. The shop I used here in Idaho Falls is no longer in business, but Troy's Machine shop in Rigby, Idaho is who I'd use today. Troy now has a CNC machine that can mill just about anything out of aluminum.

I uses the intake valves from a 144 six, which measure 1.467",for exhaust valves. I was not aware of SSI, 1.5" exhasut valves at that time. CI has them for you and they are a worthwhile upgrade when you're doing your head.

Look for a '78 - '83 head D7xx and later. These heads are on both 200 & 250 engines these years. What year is your 250 engine? With a stock cam 9:1 is a good goal CR. If you upgrade to a longer duration cam you may want to shoot for 9.2:1 at your elevation. I'm running about 9.75:1 here at 5,000 ft. elevation, but have to use an ocassional fill of 91 octane gas in the heat of the summer. Your cost estimate seems reasonable to me based on eastern Idaho prices, I don't know about your area, but if you do a little shopping and can find a shop that likes the idea of what you want to do, and is willing to work with you, you'll do better. I had the shop clean and inspect the head before I started. They did the major mods for the 2V carb adapter and cut the preliminary valve seat and told me to not touch that area. Then I took the head and went about cleaning up the ports, polishing the chambers, fitting the exhaust port divider. Then the head went back to the shop where they milled it, finished a three angle valve seat, back-cut the intakes and installed the valves. Then I took it to balance the chamber volumes, clean and paint it. The point is, how much of this work can you do/are you willing and able to do?

FYI- the albatros of the 250 engine is the huge deck clearance of the pistons. If/when you do the block, I hope you seriously consider addressing this problem. My 250 block had a deck clearance of .150"!!!! That is not untypical of a 250 engine. There are several ways to address this, but that's another post. And we've got to stop hijacking Ralf's thread.

Adios, David
 
Mike carries an adapter, several in fact:

http://www.classicinlines.com/products.asp?cat=46

These will greatly simplify the process and reduce the costs as they take all the engineering out of the conversion for the machinist. As for cost, I spent around a grand on oversize stainless back-cut valves, springs, retainers, and a full head rebuild with with new guides & machining for the adapter and to raise compression. It made a huge difference in performance even though I had been running the same carb with a funnel adapter before. I gained 700 rpm on the powerband, and significantly more power across the rev range.
 
But wouldn't the conversion actually yield the most out of the 2V carbs?

I want to build a mild motor and I never really considered what those other things you listed do the motor when the head is off of the block. Would it really be necessary to do all that? How much more HP/Torque or whatever the gains would be if you do all that other stuff when the head is off?

Cheers!
 
The adapters on the page, well, some of them (the ones with oval openings), are intended for doing a conversion. Yes, the conversion will yield major benenfits by itself without porting or big valves. You should probably get a valve job while it's in the machine shop though unless ou've had one recently.

Here si the write-up i did on mine
viewtopic.php?f=1&t=43240&start=0&hilit=head+pics
 
I haven't had any major work done to my Maverick's 6 since I've owned the car. What would a valve job to the motor? Better exhaust breathing cause that's what it sounds like to me in which case it would be a good investment.

Cheers!
 
I currently have two motors at the machine shop, a 200 and a 250. The 250 belongs to a forum member that I'm helping out. Once its done, we are going to break it in on their engine dyno. We plan to start with a stock log head, then swap to a converted head, then add high ratio rockers. Hopefully this will all happen over the next month, as the short block is almost done. We just need to assemble it.

As for the conversion, we charge $200, which includes the billet adaptor, gasket, stainless steel hardware, machine work, and labor.
 
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