# Tri- Power Loading up and backfiring



## timmyg (Jan 2, 2012)

Hello, I have a 65 GTO with a 70 HO 455 with a 66 Tri-Power set up on it. I rebuilt the Carburetors on the car just before I took the car to the Paint shop back in August. I purchased rebuild kits from I believe the name was "The Tri-power guy" or something close to that. He had the "new style kits" that had the needle seat, etc. that are supposed to be for the Ethanol that is now in Gasoline. Anyway the car is loading up very bad when you start it. The only way you can get it to run pretty decent is to disconnect the rod from the choke and hold the choke open. This makes it better but does not fix the issue. Also, once it runs awhile if you give it a moderate accelleration while sitting in park it will rev up fairly well, but if you get on it pretty good, it will backfire through the center Carb. I have rebuilt a ton of carbs. in the past and they all were fine, so I dont think it is anything I missed, but I sure could have. It also runs better when the center air cleaner is removed prior to holding the choke open. When I tried to move the car the other day out of the garage, as soon as I would put the car in gear and start to give the car some accelleration, it would cut off. It would start right back up each time. I know it could be alot of different things wrong, but I was hoping someone maybe could nail the issue down pretty close for me. I am concerned about the backfiring as I know that could be Cam related. 
Specifics of engine: Engine is 70 455HO with 66 Tri-Power set up - Mckellar#10 Solid Lift Cam - Pontiac Points Distributor.
Any advise or guidance is much appreciated.:confused


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## Rukee (Feb 8, 2007)

Check the choke pull off, it should open the choke slightly as soon as the engine starts. it may need to be adjusted.
If your using paper air filters, I would have to change them sometimes several times a week. Swap them out for some K&N filters and that problem will be done with.
The back firing could be an issue with the solid lifter cam if an intake valve is adjusted too tight.


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## BearGFR (Aug 25, 2008)

:agree Also, check all the 'basics'. Make sure the ignition timing is right, points dwell set correctly, "run" the valve lash, etc. In short, eliminate as many variables as you can then dive into whatever's left.

Bear


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