Duraspark Conversion

[kimcrwbr1]

Kim can that be used with a Holley carb? I'm getting pretty close to being done with the conversion. I've had some other issues to take care of in the process and have been taking my time. A few things I'm unsure of with the Holley carb is vacuum hook ups and the throttle and choke hook ups. It looks like the throttle linkage stud needs to be swapped out to a ball stud instead of the flat on so the cable can be a hooked up correctly. I'm also not sure if I left the electric choke wiring when removing all the junk. What should I be looking for? Also how did you guys go about blocking off the smog pump pipe to the cat?

I dont know if it will fit on a holly carb. The advance goes to the ported vacume port it will have no vacuum at an idle until you open the throttle. Take some pics of the carb will help a little better. There are two check valves for the air system one goes to the cat and the other goes to the crossover on the back of the heads you can try just putting a hose connecting the two as long as both check valves are still working That way you dont have hot exhaust going through the hose otherwise you can cut and crimp the tube as long as you dont have to pass smog tests.

 

[edwards1687]

I'll have to snap some pictures next time I get a chance. I think I have all the vacuum ports hooked or plugged up that come off the carb. I'm having a hard time figuring out how to block off that smog air pipe to the cat. That emissions valve was rusted and broke off near the firewall so it's hard to access to crimp and fold over. I haven't noticed the two on the back of the heads. One thing I was curious about was the black box on the drivers side front fend well that has the rubber lines to run up to the intake manifold/carb? I'm not sure what it is or if the lines need to be plugged?

 

[drgrcr]

It is a charcoal canister for fuel tank emission. Should have a valve inline on the vacuum line that is connected to the engine. If you just converted it to dura spark in no longer works. Disconnect and plug the port to the manifold. The fuel tank will still vent. I removed the canister from my truck and shorten the line from the tank so that it vented back at the tank. Works fine, no fuel smell. Looks cleaner in the engine compartment. I mounted the dura spark module to the bracket that held the evap canister.

 

[edwards1687]

It is a charcoal canister for fuel tank emission. Should have a valve inline on the vacuum line that is connected to the engine. If you just converted it to dura spark in no longer works. Disconnect and plug the port to the manifold. The fuel tank will still vent. I removed the canister from my truck and shorten the line from the tank so that it vented back at the tank. Works fine, no fuel smell. Looks cleaner in the engine compartment. I mounted the dura spark module to the bracket that held the evap canister.

Thanks! I was thinking that might be what that was but wasn't sure.

Kim, I think I found what throttle solenoid I need to make the A/C work properly. Holley makes a bracket and solenoid for there carbs - http://www.holley.com/data/Products/Technical/20-9 installed.pdf. I guess I need to get it running and make sure my A/C works first

 

[kimcrwbr1]

I still have the vapor cannister hooked up I just put in a restrictor in the vacuum line so it gets a steady vacuum while the engine is running it looks like the one that is on the air filter housing that goes to the preheater door. What is the size of the holly your putting on it the reason I`m asking is the 2.8 is only pulling about 290 cfm max if you running a 350 cfm holly if your jets are too big the unburnt fuel will wash down into the crankcase. I am not sure on the holly jet size but my engine runs good on #42 jets you might get a few different sizes smaller to play with?

 

[edwards1687]

I still have the vapor cannister hooked up I just put in a restrictor in the vacuum line so it gets a steady vacuum while the engine is running it looks like the one that is on the air filter housing that goes to the preheater door. What is the size of the holly your putting on it the reason I`m asking is the 2.8 is only pulling about 290 cfm max if you running a 350 cfm holly if your jets are too big the unburnt fuel will wash down into the crankcase. I am not sure on the holly jet size but my engine runs good on #42 jets you might get a few different sizes smaller to play with?

It comes with #61 jets from Holley but I swapped them out with #54's. From what I've read most guys have good luck with #54's up to #58's.

 

[edwards1687]

Ok I got the fuel pump and fuel pump push rod replaced and it is getting fuel to the carb now but it's not wanting to fire up. What is the first or best thing to check? I'm guessing I may have hooked something up wrong or maybe the timing is way off. I did take my time to make sure I hooked things up right (or so I thought).

 

[edwards1687]

Any suggestions?

 

[drgrcr]

Got spark? at the right time?

 

[kimcrwbr1]

Have you had it running yet? To find TDC on the compression stroke pull the #1 plug and stick your finger in the hole and with a wrench turn the crank clockwise until you feel compression. Line up the TC mark on the pully to the pointer and pull the distributor cap. Ideally you want the rotor pointing at 11 oclock but for now you just put the #1 plug wire on the closest tower on the cap the rotor is pointing at and then set the firing order from there. Put the timing light on the coil wire and crank on it you should get a nice steady spark. If it starts disconnect the vacuum advance and plug the hose and set the timing at 10 DBTDC. The best way is to mark the pulley one line back from the 12 degree line with a white or yellow crayon. Its easiest to see from underneath the TC is the wide groove in the pulley. Did you put the TFI coil on it? You should be able to jump a 3/4 inch gap with a spark gap tester 5/8 minimum.