Carb Choices?

[pedal2themetal45]

I'm looking for a bolt on for my 200..
I have a 250 head on it so I have the bigger carb hole and its milled .60 to keep some compression. I've been hoping for a RBS but no one has one I've been looking for MONTHS...
The carbs I have found are.
Two of them are Holly II's the one for a
200 cu. is a part number of 411089
and the one for the 250 its 641090
I wonder what the differents is?
and then one for a 240 truck motor and it is a Champion rebuilt part number 6736. Would that one be to big for my 200?

Thanks All
Tim

 

[CZLN6]

Howdy back Tim:

None of those numbers worked in my data base. I'm guessing they are later then '79 Holley 1946 models. if that is the case, I can help you as I have avoided them because of their complexity. They were the last carb used prior to EFI and were crutched in many ways to comply with the EPA standards of that era. The cfm ratings were in the 180 to 190 ranges, but I believe them to be optimistic. For comparison, take a look down the throat of one of the 1946s and a YF or 1100. You'll see what I mean.

The 240 was the "Big" six used in full sized Ford cars. I believe the last carb used in that application was an EPA version of the Carter YF. It may have some use. Mustang Geezer tried to adapt a YF from a 300 six truck with limited success.

The RBS is rated at 215 cfm and is a simple carb to work on and to tune. I seem to recall the 300 YF was rated in the 225 cfm range, but had an internal idle circuit that was way too rich for our applications.

What is the casting code on your head? 200 and 250 heads become identical after about 1970.

About the best bet for a one barrel bolt on for your engine is to continue looking for an RBS (215 cfm) or an Autolite 1101 (210 cfm) from a '69 Mustang with a 250 six. Either will be compatible with a '69 and later, non Load-O-Matic distributor.

Sorry I couldn't be more helpful. Good luck.

Adios, David

 

[Bort62]

I have had good success with a YF from a 300 six.

However, I have not paid explicit attention to the finer details of driveability so I can't give too many recomendations there.

It was easy to rebuild and seems to perform well.

I've now modified the snot out of it to get me enough fuel w/ the turbo, so it isn't worth much as an example anymore

I wouldn't hesistate to use another on a NA six in the future... Idle mixture ratio issues should be solveable by adjusting the size of the idle jet, and the main jet is compatible with edlebrock AFB jets.

 

[kirkallen143]

I had really good success w/ the 240 version YF carb on my stock 200. Seat of the pants difference, especially w/ engine under a load like up steep inclines on the road.

Doug (mustang geezer) tried the 300 version YF, and had great results, even with his high compression engine he had. I believe his CR is up to 11 to 1 or around that.

Good luck and let us know your choice.

Kirk