I installed a Holley 570 cfm Street Avenger & Holley high performance 80gph on my 302. I know I should have give it a better air/fuel mixture but how do I know how much air I should give it? Plus if anyone can give me on some pointers on how to get my 302 running right with my Holley upgrades I would appreciate it very much. I plan on working on it this weekend so I would like all my bases covered before then.

Also why do I see more smoke out of one tail pipe then the other?

 

You just need to drive it, then pull the spark plugs to see if they are white(too lean) or black(too rich) and make your jet adjustments from there.

 

I agree with LXman. The best way to tell what your engine is doing is to read the plugs. Make sure you ing. timeing is correct and check your air and fuel filters are in good shape before you start tuneing. Go buy you a good large dial vacuume gauge and use it to set the idle side of your carb. Ive seen carbs set to rich on the idle side but be to lean on the power (part throttle ) and wide open side. The plugs would still look as if the engine was running rich becuase of so much fuel on the idle side. I always get the idle circuit right then the power enrichment and then make sure its not to lean at wide open throttle. Hope this helps its always worked for me.

 

As said before, New air filter and fuel filter and set the timing. The first thing is to check the floats are adjusted correctly. Floats too high or low will cause driveability problems. After the floats adjust the idle mixture and set the idle speed. Make very small adjustmens or as few as needed to the carb and wright them down. then drive the vehicle and note any change.

 

My vaccuum pressure is 21 psi with my current settings on my carburetor. I did not adjust the floats because Holley said that the carburetor comes set almost to all factory settings so very little adjustment would be needed if any. I ran the motor like than and came to the conclusion that I should ask on this forum. Secondly I have the timing set at 8 degrees BTDC which is what the 1979 specs call for but someone suggested to timing down to 6 degrees because he got better repsonse under a heavy pedal at 6 degrees and someone else suggest to time it up to 10 degrees. My fuel filter is pretty new and my air filter is brand new, 2 weeks old, and I was thinking about a compression check too. That is where I stand at the moment and hopefully thsi helps you so you can guide me some more. Thanks for the replies too.

 

How is it running now? If it is good, then it may not need any tuning.

 

Well for starters my acceleration sucks. When I get to a certain point on the accelerator it sounds like the motor is almost like its drowning out. I cen feel the motor suffer when I hit the gas and the sad thing is that I am not even talking about flooring it. It just does not run like is should. Then when I am warming up the truck you can hear an inconsistent spudder while the engine runs but only when it's warming up. Once I hit the gas and the motor revs down it does not do it. Only when warming and the engine is reving higher. So like I said the acceleration sucks, the motor cries at a certain point and the inconsistent spudder has me to believe that it's all related some how. I know this may sound kind of hokey but trying to put the motor descriptions into words is not as easy as it sounds. Hopefully you understand and can tell me what is wrong or what you think the possibilities are. Thanks.

 

How was the truck running before the upgrades? Were any of these problems noted before the Holley pieces were installed? Will the engine rev up(no load) slowly and run OK?

 

No I did not have any of these problems before the upgrade. My old 302 ran smooth and fine. This one runs fine as long as I slowly run the motor. If I floor it it's quite depressing because it down right sucks. The only time my acceleration is adequate is when I am running top end. At 55 mph I can pick up ok but anything before the and the motor suffers. Not to sound stupid but do you know off hand how high or low I should set my floats with the given upgrades that I have?

 

The fuel level should be set so it is at the bottom of the sight plug in the side of the fuel bowls. Also check to be sure the vacuum advance line for the dizzy is connected to the proper port on the carb, inadequate advance can cause those symtoms. The smoke out one tailpipe is what color?

 

The sight plugs came installed on the carburetor but I removed them because the instructions said they are for temporary use only and not full time use. So I did not know any better so I left them in. Now I put the vaccuum line on the carburetor for the vaccuum advance on the exact smae location it illustrated in the diagram within the instructions. I noticed my motor running funny so I installed the line on the port I used with my old 600 cfm Holley carburetor and it made a dramatic improvement. Now I even double checked it to make sure and it was installed according to the directions but I now have it on the other port located on side the fuel bowl. The instructions have it to installed on a port on the bottom side of the carburetor next to a bigger port which I believe is the PC port. So I do not know that should have thrown up a flag but since it was running better with the vaccuum on the new port I never gave it much though since then. Do you think I may have a faulty carburetor? It's only 5 months old and well within warranty. Hope this helps you because I stuck like Chuck on this issue.

The tailpipes do not "smoke". See in the morning when the air is cooler as the truck warms up I notice that one tail pipe is blowing more than the other which is noticable because the cool morning air clings to the exhaust kind of like when you can see your breath in cold weather. The exhaust is not blowing any grey or black smoke. Nothing like that but I noticed my right pipe is definetly blowing more. I hope its not a serious problem but with my luck it is. This truck is turning into one giant problem and not to mention a serious money pit. Hopefully I can find the problem and finally be rid of all this knick knack B.S. Thanks for all your help thus far.

 

What I meant to say in my first paragraph is that I did not leave the sight plugs in due to the fact that the instructions labeled them for temporary use only.

 

Sounds like it may be running too lean. You may need to go up a couple of jet sizes.
What is the initial timing set at? It could be too slow as well.

 

My timing is set at 8 degrees BTDC which is what the '79 specs call for. Somone suggested to turn it down to 6 degrees BTDC because he got a better response under a heavy pedal and several other people suggested turning it up to 10 degrees BTDC. I think I shoud adjust it because it often is sluggish when starting after the motor is warm and sometimes I have to give it gas. I was thinking about turning it up rather than down. I am going to install my sight plugs today on my lunch break and hopefully get my fuel set right. Now you suggested going up a few sizes in jets but can you suggest a size? Where would I get such a product? Autozone? Napa? Internet? Are the jets easy to change? I never took apart a carburetor before so I may buy a manual on Ebay.

Hopefully I'll have enough time on my lunch break to fool with my truck so I can get back to you later on this afternoon and let you know where I stand.

I really appreciate all your help. I do not mean to sound like a broken record but I need to learn how to deal with this crap and all these ideas are really helpful. Thanks.

 

I installed my sight plugs and once the engine was idled right it started raining so I could not do any more to it at the moment. I noticed a couple of things though. I noticed the very top of the front fuel bowl bolts on to the block looks like it leaked. I did not tighten the bolts. Secondly I could not even see the fuel inthe fuel bowls. You said the fuel should be at the bottom of the sight plug and I could not even see it. Now the elbow on my vaccuum line for the advance broke off so I just put a longer piece of hose to reach. Someone suggested getting a bigger line for the advance because the one I have is kind of skinny. What about changing the advance? Or is that too drastic as of the moment? Once the weather clears up I'll try it again and holler back so I can update you on my progress if any.