ThirdGenLS1

iTrader: (11)

Looking for some opinions on my build right now. I'm putting together a 370 iron block currently right now since thats the best option i see right now for my budget.

I currently have dart 225 heads out of the box which made good power with my previous set up so would like to keep them. The problem lies with what exactly to do with them, i called dart and they do have a cnc program for there heads which open them up for a 4 inch bore and the price fits great into the budget, bu the problem lies to if this cnc job would be right for me.

Heres the flow numbers from there ported head.

INTAKE 144 214 264 305 329 344
EXHAUST 114 157 192 219 232 240
0.200 0.300 0.400 0.500 0.550 0.600

And heres stock just for you to compare of the 225 head.

INTAKE 144 202 254 290 301 313
EXHAUST 214 109 154 187 205 210
0.200 0.300 0.400 0.500 0.550 0.600

Both heads were flowed on a 4.03 bore on a superflow 600

There ported head version has a 250cc intake runner and a 90cc exhaust runner.

The intake seems pretty big even for a 370 inch motor but dart has told me that they would do well for my set up. I have been reading and i know flow numbers and cc's dont tell the whole story and you can have a big head that will still make good power through the band.

I'm also aware that mid flow numbers are really important and looking at the flow sheet the ported version do flow more in the mid range but with the added cc's of the head i'm unsure of the actual outcome.

I'm planning on running a cam in the 240/246ish range give or take depending on what the final specs become. I'm looking for a 3k-7k rpm band, basicly a car that is a blast to drive during the summer and will make it to the track 2-3 times a month.

Basicly i'm trying to figure out if the port job is worth it and will make more power then say if i just opened up the chamber for a 4inch bore and called it a day.

Sorry for the really long post but i'm looking for any kind of input, and i would really appreciate it if i got responses from people who know something about this.

Thanks a lot
Justin

Bo White

iTrader: (59)

I ported a set of 225s not too long ago for an "all out" car and they went over 240cc. The low lift #s look good for a large port so you shouldnt loose any low end over the stock casting Dart.

ThirdGenLS1

iTrader: (11)

thanks a lot bo you are the kind of people on the board i was hoping to get opinions from.

Bo White

iTrader: (59)

The thing about the 225s are they dont cc out at 225 as cast....atleast the ones Ive ported hadnt. More like 230-235cc

ThirdGenLS1

iTrader: (11)

so do you think when dart tells me there cc on there ported heads are 250 that they are really 250cc's ?

Bo White

iTrader: (59)

It may be wierd but I would think so or close. Like production castings I have seen anywere from 198-204cc on LS1s and 209-213 on LS6. Sure, 235 is not 225 but Ive also only ported 3 sets and 1 set I didnt cc.

ThirdGenLS1

iTrader: (11)

bump for more opinions