1969 nos chambered exhust

[Chevy454]

It looks like the diagrams on page 4 of the stuff I posted are backwards then? Looks like they have the chambers clamped and the mufflers welded?

And the ZL1 cam would definitely magnify the problem...too much duration and a very restrictive exhaust is a bad, bad combo! Yeah, our system was the 2.5" transverse Flowmaster system...the engine was rebuilt to factory specs, and was a whopping 10.2:1 compression, but was bracket car consistent...I did pretty decent at a couple bracket races, even on the skinny tires. Anyway, it's interesting you mention fuel...I bumped the compression up to 12:1, and am now running 12.3 @ 113+ (on Polys) with the stock AC fuel pump and factory lines. I did an A-B-A test with a 130gph pump this summer, and the car ran just as well with the stock AC, so that's what's on it, and what looks best!