HI guys, I have a sbf dart block 349c all forged bottom end 9 to 1 compression. It has a 850 c&s carb and intercooler air to water. Right now, i am running a gt47 88mm turbo and vp c16 fuel,the msd #7535 . I would like to make it run 20 psi and up and need some pointers about where I should start and end with timing boosted and unboosted so can anybody help me with that ?

 

Redline/cam/head and CC design?

Always start overly low. Say 10-15*. Dial in your AFR and peak boost, then bump a degree at a time watching plugs. With a healthy cam that fuel/setup will like 24-32* of timing I'd guess. The plugs will tell you when to stop.

 

I'm in the same boat as dartblock and am new to this so what are you looking for on the plugs?
Thanks Carter

 

The ground strap will have a heat mark . Do some searching and read up as much as possible. If you don't get it right you will find out the hard way. Here are a few examples of what you are looking for not all are as easyto see.

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This will tell you if your in the right heat range for your engine. But, don't you have to read the white porcine part to look for detonation?

 

Minor detonation shows up as little balls or specs on the porcelain/electrode/base ring. They will vary in size and amount depending on how bad your detonating. Severe detonation will melt the whole strap.





Also any reading needs to be done on a new plug (with very little idle/cruise time) right after a pull with the engine immediately shut down for the best read. Trying to read a plug that’s been in a motor for 3 months is impossible.

 

Pretty cool info on the plugs, learn something new everyday.