I beleive the 503 is the 24/230 XE grind.

I would go the 230/236 CC XE grind with 1.6 rockers and the ported heads. It should easily get you 400 HP at the crank.

 

Something like a LE1 if you want a strong driver.

Bret

 

With out heads or cam I am about 380s at the crank, I would like to have 400rwhp when it is all said and done.

 

Then that extra 20 hp should be easy to get.

 

That sounds a little high for headers and rr's. I've seen people with full boltons and a hotcam not even get those numbers.

Benji

 

That's what the guy at the dyno said.

full list I can think of on the top of my head is

Long tubes

open exhaust, to a off road y pipe

cold air

tune

ported MAF

1.6 RR

250lh fuel pump


There may be a few other small things...but as you can see the RR and the LTs are the only real mods.