I put an original GM spring back on and went for a spin at 40 degree temperature with the spring hooked up this morning. I didn't get stopped by vapor lock, but the gas still percolates a bit. Maybe the gas comes from China too.

1946 Chevy pickup, 1948 Chevy suburban, 1950 Chevy pickup, 1952 GMC pickup, 1957 Chevy pickup, 1939 Chevy pickup