triple carbs recomendations

[Anonymous]

just getting my 205" ( .060 over) ready to run. working on the carbs. will setup the timing and etc this weekend with a single stock 1100 on the center hole with the end holes capped. will be working on a set of 1904's to get it fully together and wanted any advice on jetting and or timing advance details any of you experienced.

i have a stock 68 head with small chambers and stock valve size but with inserts. mild porting to cleanup and portmatch at the exhaust. and a .020 cut on the face to cleanup with about 51cc chambers. the cam is fordsixparts 264-12 single pattern( .44 valve lift) and a pacemaker(fordsixparts dual exhaust header). i am running a C-4 with .283 rear axle and 225/75 x 14 on the back. also i figure i am right at 9:1 on thr compression

i expect this has been covered here but i dont have any time to do a lot of searching since they pulled the plug on work web use. so if there is a general direction or consensus of advice i would appreciate it.

i was thinking about either running three of the smaller 1904's on a straight non progressive and would like your comments and jetting recommendation. the HRM article started at 54-55 for a 144"

or possibly a bigger bore for the center 1908/1909 or whatever and the 1904's on the end with a progressive setup. anyone try this and if so what should i try for jetting?

i currently am using a 68 distributor with vaccum advance an vaccuum retard disconected, and a pertronix with matching coil. i expect i will have to weaken the spring on the vacuum advance to make it more sensitve or disconnect it altogether and try to get a wider quicker curve on the centrifugal advance

also i am running dual 2" through turbos all the way to the back.

i use the car mainly for freeway commuting and am interested in the performance mostly for keeping up with the SUV's( which it did pretty good anyway tired as it was)

but it should have a nice awakening if i can keep away from over carbing
or preigniting

also i am adding a 160 sq-in modine oil cooler for the engine oil and a tripple filter setup. this is by means of a spin-on adapter with filter and dual remote filter. my radiator is a new 2 row but i will upgrade to something bigger if need.

thanks for any advice frankie

 

[CZLN6]

Howdy Frankie:

If your stock Autolite 1100 is also a '68 it may be fine as is. If it is a '68 it will not have a Spark Control Valve, it will be a 1.10" venturi flowing 150 cfm and should be jetted about right for SoCal. Do you still have the automatic choke?

You have a good idea to just use the center carb for initial start up and break in. You may be overdoing it a little with add on oil coolers and filters. Make sure that your coolant and oil is getting up to a good operating temp for break in.

You will need to verify which Holley #1904, #1908 and #1909 you will be using. These carbs were used on 144s and 170s and the cfm changed accordingly. The 144s were flowed at 130 cfm. The 170s at 150 cfm. They were jetted differently in each application. In either case, I think I'd start with standard jetting and assess from there. The way to assess jetting on the outboard carbs is with WOT tests with fresh plugs. Too much idling will ruin the read.

I would strongly suggest that you use progressive linkage with this setup.

Hook the '68 distributor to the ported source on the stock '68 1100. If you have tight closure on the end throttle plates it should work fairly normal. Once the end carbs begin to open the vacuum signal will be out of the normal range. At that point you will be relying on initial and centrifugal advance to do the job. The centrifugal advance springs could surely be lightened to hasten that curve.

Know that you are over-geared and over-tired for this engine/trans combo. You will have this engine lugging often. For a start, consider 205x70x14" on the rear for a much smaller tire circumference. A 3.00:1 rear with a looser converter would also help.

Please keep us posted on your progress.

Adios, David

 

[Anonymous]

yes it is a stock 68 carb but i am not sure it is a california car. it didnt have the smog pump. the car was running real good just tired , using some oil. the plugs were reading always white maybe a little hot and lean. some preignition on steep hills.
but when i opened it up there was a lot of carbon, maybe 3/16" in some places. this was on a head only 20,000 miles old. one of the center exhaust valves was right on the edge of burning, but i found a missing sliver of gasket under the carb which may have caused that.
it is all a flat commute mostly to and from work 50 miles each way. so i liked the way the engine sounded running at 75, after i went with the big tires...not quite so busy. but it was an old engine with oiver 100,000 miles.
maybe the new engine will like the higher rpms better.

i have read about the plug readings process but never actually tried it to adjust jetting. but i hadnt degreed a cam until now either!!!! so i guess there a first for everyhting.

i have really benefitted from the book, this website and discussion with fordsixparts. Thanks for everyones support