What do you think about 1-3/4"OD primaries, and a 2-1/2" OD on the log itself? It makes sence to me to make the Log 2-1/2" since that's how large the collector is on my long tube headers.

So, for a single setup, I'd run a 2-1/2" cross over tube as well, and a 3" down tube.

Any opinions?

 

I built my logs with 1-3/4 ID and 2-1/2 ID for my 455 Pontiac. But I haven't run the car yet. I used a 2-1/2 cross over and my TV75 has a 5" downpipe

 

those are BEEFY! A nice job too, I might add! I think those dimensions will work for a 302, since the crossover tube/left header will taper down into a T4 flange for a T-62ish hair drier. I'll get all of my velocity from that merge point.

I could be wrong though...

But I DO think the bigger size on the Log will cut down on hot spots, and I'll try to use bends on the primaries in the direction of flow to keep turbulance down as well. Also, I could neck down the crossover tube to a 2" piece to kick velocity up a bit, but I'm trying to find out what other people think, as well as comparing against commercial stuff.

I wanna' build something that will grow with larger tubos, as I continue to blow major coin on this stuff... It could be worse. I could blow it all on Crack.

 

i'm running 1.625" pri, 2.5" log, 2.5" crossover on my setup. seems to work ok.