I think you can scare 'em a lot easier / cheaper;(edit; oops sorry, erase cheaper/easier and substitute "just as well"), with a little re-engineering of the current combo. Your manifolds and small carb are killing your 360, and the 3.55s are like tying it to a tank.
That 380 motor has a pretty big cam in it the power peaks at around 5500, but the power only falls off a tiny bit by 6000. And Ima thinking it could go another 300 or 400 more after that.So lets call the 1-2 shift at 6300, which drops into second at 4540; yeah that looks about right.
But I bet you are short shifting it at maybe 6000, and dropping into second at 4430rpm, and the power there is about 350; look at the dyno-chart.
The thing is with 3.55s, 6000 is 53mph., and now
With only 9/1 scr and that big 288/292/108 cam in it, the cylinder pressure is about 131psi @ sealevel and the VP is a mediocre 104.
And therein lies part of the problem
For performance in my streeter, I gear it to hit the power plateau at or near 60-65mph. This means that you will go thru the power peak twice and annihilate the tires. Well, with the Caltracs maybe you'll just ET stupendously well.
So what gear is that"
Looking at the chart I pick 5700rpm. And with an 85" tire roll-out I get 3.82s for 62.5mph; so round up or down to 3.91s or 3.73s, depending on how much you wanna scare your passengers.
But the biggest problem still remains which is the 104VP/131Psi cylinder pressure.
