The new-style neck for a 3.5 reservoir. Howe's price list says it requires a 90 degree fitting, which you'd add separately.
- Size: 3.5
- New style
- Requires 90 degree fitting
Related: the updated 3.5 neck with radiator cap and 90 degree fitting is part 1010-1006.
Howe Performance part number 1010-1035.