7.4ltr wot, plug gap, timing?
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7.4ltr wot, plug gap, timing?
Hey guys:
I have a pair of 1999 Merc 7.4ltr engines. They now have HP500 style intake and Holly 750 carb. Edelbrock alum heads, 502 roller cams, emi thunder exhaust and msd 6al boxes with pro billet dist.
Nothing fancy, just made to breathe better.
Lower is all stock.
What is a safe wot RPM?
Plug Gap? Now set at 35 thousands
Timing? 8 deg btdc at 750-800 idle rpm
Any thoughts would be appericated.
I have a pair of 1999 Merc 7.4ltr engines. They now have HP500 style intake and Holly 750 carb. Edelbrock alum heads, 502 roller cams, emi thunder exhaust and msd 6al boxes with pro billet dist.
Nothing fancy, just made to breathe better.
Lower is all stock.
What is a safe wot RPM?
Plug Gap? Now set at 35 thousands
Timing? 8 deg btdc at 750-800 idle rpm
Any thoughts would be appericated.
#2
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Hey guys:
I have a pair of 1999 Merc 7.4ltr engines. They now have HP500 style intake and Holly 750 carb. Edelbrock alum heads, 502 roller cams, emi thunder exhaust and msd 6al boxes with pro billet dist.
Nothing fancy, just made to breathe better.
Lower is all stock.
What is a safe wot RPM?
Plug Gap? Now set at 35 thousands
Timing? 8 deg btdc at 750-800 idle rpm
Any thoughts would be appericated.
I have a pair of 1999 Merc 7.4ltr engines. They now have HP500 style intake and Holly 750 carb. Edelbrock alum heads, 502 roller cams, emi thunder exhaust and msd 6al boxes with pro billet dist.
Nothing fancy, just made to breathe better.
Lower is all stock.
What is a safe wot RPM?
Plug Gap? Now set at 35 thousands
Timing? 8 deg btdc at 750-800 idle rpm
Any thoughts would be appericated.
Last edited by getrdunn; 04-28-2010 at 11:36 PM.
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Read the owners manual on the MSD box if you have one. In most cases the shorter the curve the better. That's why you'll see many boaters who use the TB ignitions like to use the v-6 modules with a 16 degree curve. It helps get you to full advance quicker as well as cleans up the idle while allowing you to have a higher base timing. Just remember though regardless of your base timing make sure your total advance is as mentioned above. Do you use marina fuel or 92?
Last edited by getrdunn; 04-28-2010 at 11:47 PM.
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Thanks
Should have mentioned, total timing is at 34 deg .
Being as compression is stock I run 89 mid grade fuel.
I think I'm where I need to be, safe for best overall performance.
Thanks for the help.
Being as compression is stock I run 89 mid grade fuel.
I think I'm where I need to be, safe for best overall performance.
Thanks for the help.
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Open up the gap! I was running .050 with my Jacobs setup, I tried setting them at a tight .040 it scrubbed about 1mph of top end plus the idle was not a smooth. If you have the fire power use it that is what it is for!