Bootybandit Posted July 3 Author Share Posted July 3 I don't know what timing set you have in your Bronco. "If" as in if it has a proper straight up timing chain, then you can consider advancing the ignition timing for more power. But you don't have an ignition module that automatically retards the timing while cranking. That may cause laboured starts and kickback. It will certainly strain the starter and may hurt instead of help. There's thousands of members here. I can't possibly remember all their details, and your sig says nothing about a cam or timing gear set.... I don't even know either, not sure how to tell. I'll just keep it at 10 but will go to the air fuel and see what I get. Ive had a hard time in the past noticing the movement on the gauge. But I do know I can always go back to 1 and half turns if I screw up. Thanks again for all the help Ill post results. Link to comment Share on other sites More sharing options...
Bootybandit Posted July 3 Author Share Posted July 3 I don't even know either, not sure how to tell. I'll just keep it at 10 but will go to the air fuel and see what I get. Ive had a hard time in the past noticing the movement on the gauge. But I do know I can always go back to 1 and half turns if I screw up. Thanks again for all the help Ill post results. Ok this is never ending. Set the mixing screw from 15 psi to 17 but what Ive noticed..... Is that with the engine running the throttle won't snap back all the down and rest on the curb idle screw Only when its off. Am I crazy? Its very snappy with the engine off but slowly returns with the engine running. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted July 3 Share Posted July 3 Ok this is never ending. Set the mixing screw from 15 psi to 17 but what Ive noticed..... Is that with the engine running the throttle won't snap back all the down and rest on the curb idle screw Only when its off. Am I crazy? Its very snappy with the engine off but slowly returns with the engine running. Bill Vose is our resident carburetor expert. I will ping him.... I can tell you that GM did have a 5 pin HEI module with retard You can use the (I) terminal of the fender mounted starter relay to trigger it. They were found in 1980 Toranado's... Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted July 4 Share Posted July 4 Bill Vose is our resident carburetor expert. I will ping him.... I can tell you that GM did have a 5 pin HEI module with retard You can use the (I) terminal of the fender mounted starter relay to trigger it. They were found in 1980 Toranado's... I've been thinking about this... You say you can only get 17" of vacuum but the throttle won't close while running, and the engine won't idle at 650 like it should. Your build includes HEI, heads, headers, an Edelbrock intake and a 4160 carb.... (no mention of cam, compression ratio, carb CFM, model of intake, primary and collector size or muffler and tailpipe diameter) We definitely need more information before trying to tune a vehicle over the internet. Pretend we are completely blind... because basically we are! Did you buy the Bronco with all this installed? If so, can you ask the previous owner about it? Low vacuum and not wanting to idle down sounds like a mean cam, or a massive vacuum leak! But, that kinda precludes the part where there's so much vacuum that the throttle won't close while running. Is the carb warped from over tightening? Have you tried adding a second/stiffer throttle spring? Hopefully Bill can chime in about your carb tuning. Link to comment Share on other sites More sharing options...
85lebaront2 Posted July 4 Share Posted July 4 I've been thinking about this... You say you can only get 17" of vacuum but the throttle won't close while running, and the engine won't idle at 650 like it should. Your build includes HEI, heads, headers, an Edelbrock intake and a 4160 carb.... (no mention of cam, compression ratio, carb CFM, model of intake, primary and collector size or muffler and tailpipe diameter) We definitely need more information before trying to tune a vehicle over the internet. Pretend we are completely blind... because basically we are! Did you buy the Bronco with all this installed? If so, can you ask the previous owner about it? Low vacuum and not wanting to idle down sounds like a mean cam, or a massive vacuum leak! But, that kinda precludes the part where there's so much vacuum that the throttle won't close while running. Is the carb warped from over tightening? Have you tried adding a second/stiffer throttle spring? Hopefully Bill can chime in about your carb tuning. Jim, there are some strange goings on. I can't fathom a reason the throttle is staying open at idle, unless he has a cruise control with a leaking valve in it. If he has cruise control, I would start by disconnecting it from the carburetor linkage. If the throttle is part way open, the idle mixture screws won't have much if any effect. Saying he has a Holley 4160 is like saying he has an AFB or AVS or 4GC or Quadrajet. It is simply a model number. I have a 4150, model, list number 4609, Ford PN C9AF-9510-U which happens to be a 1969 428 CJ carburetor for a vehicle with a C6. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted July 4 Share Posted July 4 Jim, there are some strange goings on. I can't fathom a reason the throttle is staying open at idle, unless he has a cruise control with a leaking valve in it. If he has cruise control, I would start by disconnecting it from the carburetor linkage. If the throttle is part way open, the idle mixture screws won't have much if any effect. Saying he has a Holley 4160 is like saying he has an AFB or AVS or 4GC or Quadrajet. It is simply a model number. I have a 4150, model, list number 4609, Ford PN C9AF-9510-U which happens to be a 1969 428 CJ carburetor for a vehicle with a C6. I get it. Simply disconnect the bead chain. I also understand "4160" can be anything! What would help is a photo of the build & list #'s on the front of the choke horn... Link to comment Share on other sites More sharing options...
Bootybandit Posted July 4 Author Share Posted July 4 I get it. Simply disconnect the bead chain. I also understand "4160" can be anything! What would help is a photo of the build & list #'s on the front of the choke horn... I bought the truck and drove it home and had now idea what had been done to it. I just replaced the holley 4160 with a Carter AFB. I put the headers on because one of exhaust manifolds were cracked and the headers here actually cheaper. As far as what's been done to the motor I have no idea. I was just hoping there was a reason a carb would not close when running but would close when off. Could be the throttle spring needs replacing. It is pretty old. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted July 4 Share Posted July 4 I bought the truck and drove it home and had now idea what had been done to it. I just replaced the holley 4160 with a Carter AFB. I put the headers on because one of exhaust manifolds were cracked and the headers here actually cheaper. As far as what's been done to the motor I have no idea. I was just hoping there was a reason a carb would not close when running but would close when off. Could be the throttle spring needs replacing. It is pretty old. Okay, so it has an Edelbrock and not a Holley? There should be numbers stamped on the base flange near the passenger front bolt. Can you tell us what they are? Is there any way to ask the old owner what they did to the engine? Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted July 4 Share Posted July 4 Okay, so it has an Edelbrock and not a Holley? There should be numbers stamped on the base flange near the passenger front bolt. Can you tell us what they are? Is there any way to ask the old owner what they did to the engine? I can buy CI Windsor manifolds all day long for $45-50 + $19 shipping. You must have found quite a deal on headers! Link to comment Share on other sites More sharing options...
Bootybandit Posted July 4 Author Share Posted July 4 I can buy CI Windsor manifolds all day long for $45-50 + $19 shipping. You must have found quite a deal on headers! I bought the Holley and manifold combo from Summit. The manifold is a Summit brand I'll check the numbers on it. My current AFB carb is # H1 9627S Link to comment Share on other sites More sharing options...
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