[RRF]

I need to know the correct timing for my setup. I have a '73 400 with 4X heads, a 290/465 cam, a '70 cast highrise intake and Hooker Comp headers in my '81 T/A. I am using the carb from the turbo T/A, which is a 800 cfm Quadrajet. I am not sure about the jets, but have purchased a set of 72's to install soon if stock jets turn out to be smaller.
The idle is very erratic when in drive. I had the timing set at 14 degrees, but recently read on a Pontiac page that 11 degrees was recommended at 1000 rpm. I setup to that spec but car did not seem as quick off the line and lags slightly now. Any help would be greatly appreciated.

[RRF]

I need to know the correct timing for my setup. I have a '73 400 with 4X heads, a 290/465 cam, a '70 cast highrise intake and Hooker Comp headers in my '81 T/A. I am using the carb from the turbo T/A, which is a 800 cfm Quadrajet. I am not sure about the jets, but have purchased a set of 72's to install soon if stock jets turn out to be smaller.
The idle is very erratic when in drive. I had the timing set at 14 degrees, but recently read on a Pontiac page that 11 degrees was recommended at 1000 rpm. I setup to that spec but car did not seem as quick off the line and lags slightly now. Any help would be greatly appreciated.

[RRF]

I just remembered Jim Hand's article, so I will apply some of his recommendations. From his page I realized my spark plug gaps are too high. I probably should have mentioned the heads have been done with good springs, competition valve job, gasket matched, and mild port work. And the coolant port has been matched to the intake. (that question always comes up from experienced pontiac guys). (Forged pistons, balanced etc.)Next step may be to mill heads a bit for more compression. Best part of this ex Turbo T/A is the body in and out is mint, with the original metallic maple lacquer paint and decals. Only it is a lot stronger than the 4.9 turbo advertised by the decals. [img]/infopop/emoticons/icon_smile.gif[/img]

[Bill Boyle]

Your terminology (290/465) has me puzzled. What does the 290 represent? Advertized duration on intake and exhaust? Something else? What about 465? Is that a reference to valve lift?
What is your cams duration at .050" lift for the intake and exhaust--those numbers are more important and realistic for us to assess. Also clarify the lift with 1.5 rocker ratio. The info should be on your cam card.
Bill Boyle

[This message has been edited by Bill Boyle (edited 06-14-2000).]

[RRF]

Unfortunately, when I bought the motor from a guy who had a fire in the interior of his 1970 firebird, all he had was a card indicating 290 duration and .465 lift. I don't know anything else about the cam. Since I assume it is not a split duration pontiac cam, I was planning to replace it one day.