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[bbboswell]

What size primaries are y’all running on 550’s hp big blocks?

 

[crazycoonass]

I'm having a 540ci bbc being built right now. I plan on going long tube 2'' primaries with 4'' collectors.Big engine, big tubes to get the hot gases out.
Also I'll be making about 740hp.

 

[bbboswell]

I'm having a 540ci bbc being built right now. I plan on going long tube 2'' primaries with 4'' collectors.Big engine, big tubes to get the hot gases out.
Also I'll be making about 740hp.

Thanks for the input.

454 @ 540hp and I have always run 1-3/4 primary 3” collector but engine builder wants 2” primary long tubes. I always thought the smaller tubes aided scavenging to help tongue but he thinks they are over scavenging and pulling still burning fuel into the exhaust which was causing my header glow issues.

 

[crazycoonass]

Header glow? Hmmm. That sounds more like a timing problem. Or possibly a lean carb.

 

[bbboswell]

Header glow? Hmmm. That sounds more like a timing problem. Or possibly a lean carb.

Plug color was good and no run on after shut down