Merge collectors

[Gary Smith]

Originally Posted by Darrin Christen

Interesting read. What would be the tell tale signs that a engine may be over scavenging? Anything noticeable in the tune up that would be an indicator of this condition?

The topic of lean rear cylinders is what drove my question. We haven't even run the motor yet, not looking for gains, just don't want to go backwards. Headers are nothing special...straight 2" primaries about 40" length. Last year we made some fixes (new fuel pump) and added 13" to the collectors and picked up 2 tenths. I suspect much was from the exhaust. But everything is bigger now, with lots of other changes with same basic induction. We'll probably put straight 4" collectors on to start. FYI this is not for my stocker. It's a bracket motor built with a lot of S/S technology.