View Full Version : tuning help

12-30-2013, 09:53 AM
Iv got no.idea.how to tune an engine ...it runs but craps out when u get on t he throttle.. i got tools and beers if anybody can come help out.. im located on No.3 rd near yarrow.
Engine is a 1978 460..plz help me im wanting to learn but have no idea where.to.start.

12-30-2013, 04:41 PM
some quick things to look at , plug air cleaner and fuel fliter, thats easy if still no go live in the wack so can stop by .

12-30-2013, 05:02 PM
what kinda carb?

12-31-2013, 01:14 PM
Everythings new so it shouldnt be plugged up.. the carb is a brand new holley truck avenger 770cfm..everything works, truck idles fine an revs up in neutral but under load it craps out spits and pops... I just dont really no what im doun anymore so i need help tuni.g..

12-31-2013, 02:14 PM
Timing or Vacuum leak?

In The Zone
12-31-2013, 02:47 PM
sounds like the timing is retarded ...is it poping on deceleraton?

12-31-2013, 02:48 PM
word of warning the truck avenger carbs suck. I am a holley fan have used them and played with them since I was a kid, learned from my old man and his engine guy when they drag raced. I would not use a vacum secondary holley on anything other than a country putt putt driver. On a 460 I would use a 750 to 800 double pumper and from there you are going to have to tune. Anybody that thinks you can drop a generic carb on an engine and it is set up right needs to give their head a shake.

Sounds like on your's it needs some acc pump adjusting. From idle you will want just a little bit of slack between the pump arm and adj spring. You might need to change pump cams. Might need to change squirt nozzle size. Guaranteed you will need to change jets and power valve.

12-31-2013, 03:24 PM
I agree with nutbar and its isn't easy to set up a carb like that without a basic knowledge so go on you tube .also check the cap rotor and wires also points ect...

12-31-2013, 05:26 PM
Ok...couple questions.
1. Is it a new carb out of the box or a used one that you picked up?
2. was your 460 running with another carb and then you put this one on?
3. Vacuum leaks check'd and corrected?
4. Timing at least set roughly

I can help you set it up over the phone if you don't have it done alread

dirka dave
12-31-2013, 07:53 PM
Easy fix.
Swap in a 350.

12-31-2013, 08:13 PM
My old 93 with the 460 in it (1970) had a 650 Holley and worked great once the floats were set and the distributor was recurved at Marks ... in Abbotsford but before I did that it was very hard to drive a couple things to also check if you tell Mark what you got and running he will check it all out and set it up proper. Its better to set up stuff when the rest is working properly ;-)