Hi i just bought a 74 comet and any help would be appreciated. specs: 302 engine ram tunnel air intake and 2 660 holley 4 barrels i believe that they removed some emission controls, engine steam comes out the passenger side valve cover, i think this this is to be sent back into the carb or both i dont know? was there a catalytic converter on it? and what other possible emission control where stock? Also i have no idea what the rpm should and if it should different from stock because of the mods, i have it set to 600 rpm now. thanks!
If the engine idles at 600 rpm then a ram style manifold and two carburetors is way too much for the engine. What you need is a nice dual plane (idle to 5500 rpm) manifold and a single 550 - 600 cfm carb.
carbs would be the right size if you were running 408 stroked 351w. (Way overkill on the 302.) Btw the vapor is blow by (its normal to see vapor in small amounts but if its blowing out you have problems), I suggest doing a leak down on the motor before you do anything else or compression test. (not counting the cam, but 600 rpm is low).
could the 2 660 carbs run properly if the headers where changed by the previous owner, second i am getting back firing at 3500 could this be because the floats are not properly adjusted or is this another symptom of too much carb for the 302 also i have adjusted the idle a little higher to around 700 it sounds like it runs better this way, p.s. previous owner removed chock idle flaps
a dual carb tunnel ram is a sign that the motor has been extensively modifyed. if you dont have very much experience with modifying cars then you have a big learning curve ahead of you. what is the list number stamped on the choke horn of the carbs? get a vacuum gage and hook it up to a vacuum port. what is the vacuum at idle and at 2500 rpm? can you take a few pics of the engine from different angles, and even some pics of the car and post them?
so i have disconnected the back to flaps on each carb and had a buddy hold them so they would not open all the way. and the engine ran to 5000 rpm with no back firing. i believe the engine is running to rich. i have orded a edelbrock dual plain intake manifold and i will just use one 600 carb keep the other for parts, and if that doesnt work after setting proper engine idle speed and float levels, i assume it is the timing advancer. I agree with what everyone is saying the ram air is just overkill. P.s. put in new valve covers with a pcv valve and breather on oil cap no more engine vapours in engine compartment
