Hi all i have a few questions .i have an 85 f-150; in it is an 89' 5.0 HO engine i removed the fuel injection and installed a weiand stealth dual plane intake, with a holley 4barrel; i installed a dura spark II distributor with vacuum advance and the module on the firewall.. the original spark plug gap is 054 i believe , but i want to know what is the best setting for the engine now that its carburated and also what is the best thing to set the timing on wit the vacuum advance distributor .. i figured disconected the vac advance and set the initial timing on 14 degrees but it doesnt seem to have the power that i think it should .. a friend of mine told me to set it 36-38 degrees mechanical . by seting the idle to 2400rpms wit the vac advance disconnected set it at 36-38 then leave the vac advance disconnected ..and reset the idle ;that wit the camand timing it this way i wouldnt need to use the vac advance ... someone please help me wit this .. whats the best plug gap and whats the best timing setting it has dual exhaust , E-303 Cam ,and 750 Holley carb , shift kit 2200 stall and 3.73 gears .and also in addition to what ive asked already the secondaries on the carb dont seem to want to open when i floor it i was told to change the spring in the secondary diaphragm but then somone else told me just cut the spring in 1/2 ..alladvice needed and appreciated ..

 

i hook my vacuum advance to a vacuum port that has no vacuum till the motor is revved up (ported vacuum) so it shouldnt matter if the advance is disconnected or not at idle cause the timing wont change till the motor is revved. i set mine at 8-10 deg. while idling. with the engine at 2500-3000 the base timing+mechanical+vacuum equals about 36 deg. total timing.

 

I assume you have a vacuum advance carburetor. With this style of carburetor the secondaries only open when the engine requires the additional air flow. With a 750cfm carburetor, this might never occur at anything under racing rpms.

In other words, the carburetor might be too large. This would also explain the lack of power.

 

thanks ..i removed the holey 750and installed an edelbrock 1406 600cfm Carb .. the truck is a 85 short bed with 3.73 gears and aod trans with 2200 stall converter with the duraspark distributor with vacuum advance and the initial timing set @ 14 degrees .. to me the truck stll feels slugish .. the plugs are autolite 26 set @ 052 .. the engine again is an 89 5.0 H.O ..the engine has dual exhaust with 160 termostat and 4 row radiator.. i know it wont pull like a 351w but it just dont perform as i know it should .. im wondering should i bump the timing up to 16 degrees ..

 

You are hauling around a lot of weight and pushing lots of wind with this truck. You might be expecting more than a 302 is able to deliver.

As far as timing goes, it's time for a little experimenting. Use ported vacuum for the advance and set your total timing with the vac advance disconnected. Set total at about 36 degrees and try it. Then retard it to different settings from there in about two degree increments, then try it again.