[Eric68]

I think you need another point of compression for best performance with that cam.

Also, the H-beam rods are a bit overkill. Personally I prefer the Scat I beams with 7/16" capscrew rods. Better clearance.

You will definately need to look at the valvetrain closely to get the RPM out of the hydraulic cam. It will want to run to 7 grand in a 383 so maybe beehive springs and a rev kit are in order.

 

[Eric68]

Thanks guys.

Eric68, I plan on running aluminum heads, but I am still kinda scared to go up in compression as this will be a pump gas motor. Would I be better off stepping down to the next grind cam. It would be
242/248 @ .050 and .540/.562 on the lift. Or are you thinking with the amount of overlap I would still be okay. Incidentally, what would the dynamic compression be on a setup like this?

Your dynamic compression ratio with the HR300 is way low at just over 7.1:1 like Jim said. The next size smaller cam has you up to 7.4:1 -- still too low for my tastes.

With aluminum heads you will be safe on pump premium with over 8:1 dynamic. I have run 8.6:1 DCR in my last two motors and run pump 93 octane with no issues whatsoever (I have a good tuneup though).

If you shoot for 10.5:1 static you will have lots more choices for cams in the size range you are looking at and will be nowhere close to detonation on pump gas.