Holley 2300, 5200, Weber 38 DGES, DEGV, or other?

[Anonymous]

Hello.

Before I start, here are my specs:
'73 Australian Ford Falcon XA, 250 loghead intake with a wheezy 1bbl Stromberg carb (BOV? something)

I'm currently ready to swap my Stromberg out with a more capable carb. Additionally, I'm a newbie to all of this, so this will be a learning experience for me. I'm slowly upgrading my engine, as I learn about each part, and right now, it's the carburetor.

Does anyone have any suggestions for having a stronger carb that will adjust to my engine as I replace parts such as the head to a 2V, cams, etc. etc.? I'm happy to go with rebuilt, as long it's something I can still get parts for with relative ease.

Thanks, in advance.

Makoto

 

[xctasy]

Option One

The Aussie I-bbl XB was really just a pre 69 200 up top, with small diameter log head and tiny hole for the gas to flow through. It is compatiable only with small carbs. 350 CFM 2300, or 32/36, or 5200. Not 500 Holley or 38 Weber. Aussies never got lead free gas untill 1985, mandatory in 1986, so your 73 is only designed for leaded hi-test, so you need to consider if you are going to risk valve seat recession on a stock head as in Option Two below

The 32/36 or 5200 is by far the best swap. Height is the issue with this carb. The XB's 73 Mustang-style bonnet should have enough space for a stock Clifford or whatever adaptor is used, but the XA bonnet is quite trim. You'll have to check this out. It may be okay, but the air cleaner on XA's was only 2" deap. I don't think the stud spacing on Aussie engines was different...seams to me the bolt pitches look the same. There is little option of getting a one-size fits all carb for the 1-bbl head, that will also fit the 2V, unless you do a lot of fiddly work on the existing 250 head.

Distributor is nice, simple vacum and mechanical adavance, so its no problem upgrading the carb like it is on pre 1963 US Falcons. Technically, the 32/36 or 5200 is too small, but its very economical and suits the tiny 1.3 to 1.5" hole in the manifold inlet, and its dirt cheap. The manifold is the restrictor in this engine. Its okay to about 130 hp, which you'd get with a 25/65 cam (about 270 degrees).


Option 2

Since any US log head walks over an Aussie 1-bbl, then perhaps a 1.75" 78 Granada 250 head is the best option. A 38 Weber or Holley 2300 500 cfm on that would be a great compromise on the right adaptor. Look at Mustang Geezers set-up, he uses a Holley 2300 500 cfm carb, direct mounted. The sizing of this later log is very good, and asside from some sharper 90 degree turns, it is a much better head.


Summary

Any cam with moderate lift will wake up the 250. A 2V or log, the cam needs to gain lift and duration, and theres little risk of making a dumb choice if its under 30/70 280 degrees (at lash duration), or 215 degrees at 50 thou. I'd look to domestic cams such as FSP, since they are doing some new stuff. You could get a bumpstick form Aussie, but its all a question of money.

Any headers will be similar no matter what you use, and again, there is no wrong choice, but be carefull with the gasket interferance with the head on a US head gaskets. Some 2V guys are finding there may be a slight fouling of the stud bosses on the head.

 

[addo]

You say parts should be easy to get. One way to look at it, sees the fact that a phone call to a business here, will usually see the parts airmailed the next day. You should be able to get a whole carb, no core, from Sydney or Melbourne to Tucson inside a week. Same deal goes for brake parts, whatever. To me, that qualifies as easy.

If you must buy locally, then for the current state of tune, a progressive carb will be best. It won't run very well with a 2V, so bear that in mind when installing. Overcarb the current motor and you could do what alloydave did - wash the bores. Not good.

To check clearance, I suggest you grab a tape measure. Extend the blade about 8", and sit it between the carb and rocker cover with the blade up. Slowly close the bonnet, thus pressing the tape back into the housing. Don't forget to add the thickness of the tape measure case when calculating your clearance. The Ramflo type air filters are probably the flattest.

BTW, I would change the ignition before the carb. It's a much more satisfying exercise with instant result. A Duraspark should drop right in, but reuse the gear off the old distributor.

Cheers, Adam.

 

[Anonymous]

Adam and Xecute,

Thanks a bunch for the help. Of course, that spawns more questions that I hope you can help me with.

As for getting parts from Down Under--I don't mind that at all. I'm married to a Kiwi, so even having someone walk/drive/run to a store for me isn't totally out of the question (unless I overdo it, then it's gonna be a problem).

Here we go:

So:

A Aussie 2V Head
better than:
Later-model American Log Head
better than:
Earlier-model American Log Head and any Aussie Log Head.

Is this right? BTW, if I'm right, is it the inner diameter of that log that makes the latter heads better?

If the 2V head is better than the later American log heads, could a 500 cfm carb be used on a 2V head as well? I think Ford six makes an Holley->2V head plate, so if I got the latter American head now, and the 2V head later--that might work out if I get the Holley??

I like option 2 since I'd like to go ahead and replace the valves, springs, rockers, etc. etc. anyhow.

That being the case, what is risking "valve seat recession"?

I have a lot of cam/lobe questions, but I'll wait on those until I get the stuff done that I feel confident I can do right now.

As always, thanks in advance.

Makoto

 

[Anonymous]

http://www.rmahc.com/valveseat.html

^^^
valve seat recession.

 

[Anonymous]

I bought my redline adapter plate for about $25 for my 350 Holley on a 2V. Its listed as an item to fit 350 on a 253. When I put the 500 H 2bbl on I thought it would be better to enlarge the 350 adapter plate and manifold a bit, this I did. I could not get a 500 Holley adapter plate for it.
The 250 2V likes the smaller bores of the 350 Holley which help velocity and make it feel sharper and more responsive down low in rpm. Problem is that a 250 2V can often need more that a 350. A Small barrel 4 should work well so long as its jetted up enough (thats if you can be bothered moding the manifold)
The Original 2 bbl stromberg on the 2v had 36mm bores the 500 H has 42.5mm (too big) the 350 had about 37 mm, the 390 cfm has 36.5, Im not sure what the 465 has but it would probably be ideal falling somewhere between the 39.5mm 600 4bbl and 36.5 390 4bbl. The jetting is important as I think Execute stated they only set up for about 170 hp as they come.

 

[xctasy]

So:

A Aussie 2V Head
better than:
Later-model American Log Head
better than:
Earlier-model American Log Head and any Aussie Log Head.

Is this right? BTW, if I'm right, is it the inner diameter of that log that makes the latter heads better?

If the 2V head is better than the later American log heads, could a 500 cfm carb be used on a 2V head as well? I think Ford six makes an Holley->2V head plate, so if I got the latter American head now, and the 2V head later--that might work out if I get the Holley??

I like option 2 since I'd like to go ahead and replace the valves, springs, rockers, etc. etc. anyhow.

That being the case, what is risking "valve seat recession"?

I have a lot of cam/lobe questions, but I'll wait on those until I get the stuff done that I feel confident I can do right now.

As always, thanks in advance.

Makoto

Some rules. Ideal intake runner volume is about 30 to 50% of the engine capacity (4089 cc)

Yes, the 2V is the king.It had huge ports, and loves to shift air. Adam may know the runner volume...I'd estimate 2100 cc's.Thats 50%, ideal for a screaming six.

The US large diameter log from 1970 on is good, the post 73 is better, the post 78 head is perfect with its nice big valves, bigger than 2V valves. The runner volume is about 1280cc's, and it has the large welch plugs in each end, around 1.3 inches or so from memory. That's 31%, pretty good for a streeter.

The stock XA 1-bbl is just a baby. I think the intake runner volume is about 800 cc, or about 1" drilled through to the centre 1-bbl carb. That's less than 20%. The valves are kind tiny too.

Valve seats recead only when the hard layer of TEL wears off. Some heads can run for years on unleaded if they are not reved too hard.

The later unleaded US Log heads had either induction hardened seats, which have a stronger layer of metal about 30 thou deap. Durring normal service, it does a great job. One valve cut, and its often gone, but it depends on if you do a 3-angle cut, and what the valve margin is in thou. If you want it to live a long and fruitful life, get it inserted, as not many shops can do induction hardening via 11 KV electromagnets.

Some later US Log heads were inserted from the factory, apparently. These would be the ticket, as you could cut it back a considerable amount, if your machinist had the right cutting tools.

The 2V would respond to the US Log valves and inserts as long as the water jackets don't get compromised.

Kinda complicated to give hard and fast rules. Any thing other than the stock head would be a bounus, and most modifications listed in the Falcon 6 Performance Handbook will do any head a great boost.


Check it out http://falconperformance.sundog.net/default.asp

 

[Anonymous]

My 2V has a 1.5 inch exhaust which Ive seen used in engines up to 350 HP. So Id have a hard time believing it needed to be bigger (is bigger than my log head). After porting mine my machinist said that he could fit hardened valve seats to these no problem and suggested going even bigger until I told him I thought they already were.
Im not sure if the 1.65 inlet is big enough as the Crossflows have 1.75 and 1.85s. Not sure If the 2V head would be better of not with these. Ive heard it said that a smaller valve can give a straighter shot of fuel air into a longer stroke engine. The Crossflow is designed around slightly the bigger valves.
I use Moreys valve seat protector in mine with unleaded and believe that it has the additional benefit of coating the inside of the headers and exhaust and aids the prevention of corrosion the unleaded petrol can cause.