Is that the front housing Nick might be ok whats the exhaust housing? .48 or .63?, plenty of t25 used on draw through without issues providing not too much boost and high compression. Especially with an A15. Draw through simple & effective for 100hp atw.

Clyons8 is doing log style manis for a great price, they work better in low / midrange to 5000 rpm after that equal length come on their own but only 15% improvement. Log styles are well proven for 100-280hp 4 cyls with excellent area under the graph if well tuned in DT carb or BT efi.

http://datsun1000.com/UserImages/clyo ... ifold%20Prototype%201.jpg