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Old 05-03-2013, 12:25 PM
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searching your other posts: You have a comp Thumpr cam.

This cam requires full locked out timing to idle correctly.
Lock out the distributor advance curve. set the locked timing to 38deg BTDC
It does not move with rpm.
Remove the carb and flip it over and reset the pri and sec throttles at idle for proper T slot exposure at idle.
install a new 3.5 or 4.5" rated power valve.
Reinstall ,,, set the (now locked) timing at 38deg BTDC and warm it up. reset the idle mix screws for best idle.
If the plugs are fouled replace.
Be sure the PCV valve is installed and functional. It is part of the idle system on your carb.

BE SURE the starter mounting brace bracket is installed. If yours is missing get one.
If it is hard to re start hot install and use a ignition power interupt switch

When you lock out the timing curve (38deg BTDC LOCKED full time) and get the pri and sec Tslot throttle exposure corrected and the right 3.5 or 4.5" power valve it will idle.
This is the nature of the Thumpr cams. You will need a 10" high stall torque converter. A stock converter will n ot work with
that Thumpr cam.

There is no free lunch when it comes to camshafts... The racey Pro Stock "Thumpr" idle comes at al cost.
If you don't like it replace the cam with one with a wider LSA. Less overlap.

Last edited by F-BIRD'88; 05-03-2013 at 12:36 PM.
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