None of them are 1.5.

there are 1 and 5/8ths and one a three quarters.

If you're not running a cam or ported heads, i'm sure the smaller primaries will be more ideal for your car.

the WBS headers are using what appears to be pacesetter primaries, not SSAC.

My SD's look like aaron's SSAC's after one winter, only not as bad. But getting there.

They still polish up nicely though.