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PMS · 11-06-2004, 07:09 PM

I am trying to get the most performance from a 72 LWB GMC. We have installed a new GM 350 HO w/ 330 HP and 380T. We have been playing with the timing and carb. Should you be able to kill the engine by placing your hands over the carb? Also we changed the jets from 78 pri. to 73 and sec. 78 to 75 and installed a lighter sec. spring. Now when driving the truck you can feel the sec. kick in but from a dead stop we can't get it to leave very hard - only about 10' of tire spin. The truck has a 3.42 rear with a 2800 rpm stall. Shouldn't it destroy the tires from a dead stop? The dist. advance is set-up with the second fastest curve possible. Do I need to change accelerator cams or what? Any suggestions would be helpful. Initail timing at 12 deg. with max. 28 deg. in at 3200 rpm. Am I missing something?

11-06-2004, 07:09 PM	#1
PMS Registered User Join Date: Aug 2004 Location: Overland Park, KS Posts: 79	Power Tuning I am trying to get the most performance from a 72 LWB GMC. We have installed a new GM 350 HO w/ 330 HP and 380T. We have been playing with the timing and carb. Should you be able to kill the engine by placing your hands over the carb? Also we changed the jets from 78 pri. to 73 and sec. 78 to 75 and installed a lighter sec. spring. Now when driving the truck you can feel the sec. kick in but from a dead stop we can't get it to leave very hard - only about 10' of tire spin. The truck has a 3.42 rear with a 2800 rpm stall. Shouldn't it destroy the tires from a dead stop? The dist. advance is set-up with the second fastest curve possible. Do I need to change accelerator cams or what? Any suggestions would be helpful. Initail timing at 12 deg. with max. 28 deg. in at 3200 rpm. Am I missing something?



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