Disappointing ET's with 408

Agree with the guys!

Yep needs more air in and out. In the day even 383's had 700-780 holleys, or a 650 AFB. Heck my dad's 440 had a 780 and that was in 71 when smog restrictions started. Stock q-jets on 400 firebirds were 800cfm. So with a nice 408 I think it is getting starved from about 4k up..


You really need to think of astroker like a bib block in a small package.

So yep get some more card on it, make sure it is jetted good, and sounds like you will also need more flow on the exhaust side too.

On the timing a lot of great replies too above. I would make sure you limit the total to the 34-36 range, but get as much as you can typical 16-18 initial and get it to come in quick like 2500-3000 should be all in.

I think you have at least 50-60HP in that baby that is trapped!