Racing Fuel Systems

Hello All,

Stock marine 351 ford, 18 foot boat used for skiing. List 9392 4160, block marked 8107 8108. Has the recess for the brass tube with o-rings. Very nice shape, very little corrosion.

Should I swap to a non e-tube block, or is the original emulsion tube style block ok for this application?

I have a block from an old governored truck carb, marked 7425. It has the drilling for the brass tube, which is a plus. It has .028" IFRs, and slightly smaller [.055"] PVRCs than the original's apx .061", and .028"IFRs. However, it has only one large emulsion hole into the wells. I've seen a number of blocks like this on ebay. Could/should I plug the single hole, and resize it to .028" and add a 2nd one in the lower position? If a newer 1850 style block is better, I'll source one. I can deal with the brass tube issue.

I saved this recipe for a 1850 style carb from the old forum that I would start with, unless advised to do otherwise:

An example of a good stock/mild default place to start 600 VS "recipe" (with no e-tubes and standard "old school" e-holes in air wells into main wells) is:
PMAB - 0.025"
PIAB - 0.070"
PIFR - 0.026"
P booster air correction bleeds ("e-holes") - 0.028", 2 per barrel
PMJ - #65
PVCR - 0.046" (potentially bigger when there are e-tubes in the main wells)
SMAB - 0.025"
SIAB - 0.028"
SIFR - 0.029" (secondary plate # 39)
SMJ - 0.073" (secondary plate # 39)

Thanks
Dave

Link to 9392 thread on old furum [with weird bowl screw picture]
https://www.tapatalk.com/groups/racingf ... 407#p25407

Link to thread where i got the recipe
https://www.tapatalk.com/groups/racingf ... t1897.html

1850-2 600cfm and 9834-1 600cfm used them, so not sure where the concern is. If you want to clean the emulsion tubes , drill-tap and retract the solid brass plugs. Clean and reinstall . Plug the drilled and tapped brass plug with set screw.
Use new o-rings on accelerator tube to metering block and main body.
May not be a bad idea to pull the plugs on the idle well also. Surprising what corrosion you will find there sometimes over the IFR.
I would think the marine application may require a different setup than a typical 1850 recipe. May be better to work with what you got first.

Just out of curiosity does that truck metering block happen to have an Adjustable Part Throttle ( APT ) channel near the power valve?

I don't see any odd features on the truck block. Do you have a picture of one with APT? I tried to post a picture of the truck block, but it's too big, and I can't get it to resize.

I'll take your advice on trying the original block first.

Thanks

you can see the 2 PVRC and also APT . Factory drilled channel and tapped for adjustable needle. Preset at factory . 2nd picture shows fuel comes from float side of metering block. Also so you can see at bottom of block where they drilled the channel at then plugged it with aluminum.

So there's no confusion , this is a metering block from a 1968 427 BBC Governor carb I had sitting around

LOL. With glasses, I see that the truck block does have the APT. Although, the boss for the plug on yours is not present on mine. Just a plug.

I assume that the carb that this block is from a 366 or 427. I didn't bother to note the stampings.

Here is an emulsion tube I pulled out from a junk metering block. ( Practice ) Notice where the flashlight is shining how corroded the well is . Hard to get a good picture but this extended all the way down the primary well. The other wells have already been blasted at this point. The idle well has the IFR below the brass cup plug on this metering block and was covered with corrosion also before cleaning.

This was the first time I pulled emulsion tubes from a junk metering block and I still keep it around to remind myself how to do it right and the mistake made.
Basically centre mark ( very important ) the flush sitting brass plug in the primary well of the metering block. Tuner explained this better ( many thanks to him ) on the old site. Drill with a #35 bit ( aprox .200" deep )for 6-32 screw. Picture shows screw spacer and washers to retract the plug. When reinstalling you can fill the hole in the brass plug with 6-32 x 3/16 set screw.
Also you will see in the picture the one brass plug with the emulsion tube that I drilled to deep on an angle coming out the side of the brass plug. Live and learn.
I have done this on many metering blocks since with great success.

Thank you so much. Pictures are worth a thousand words.