I'm going to be researching the different heads out there, can you post up any flow numbers with matching heads that you have or can find? I'm ultimately trying to compare ported LS6 heads to the aftermarket heads out there.

Also any differences in valve sizes and materials. I know AFR uses valve materials that reduce the risk of a valve float.

Can AFR's be ported further?
AFR 205cc Intake valve 2.020" Exhaust Valve 1.600"

Lift Intake Exhaust
.200 145 121
.300 210 173
.400 257 208
.500 290 223
.600 308 233

TRICKFLOW 215cc LS1 Heads Intake valve 2.040" Exhaust Valve 1.575"
Lift Intake Exhaust
.200 142 115
.300 215 185
.400 260 230
.500 300 251
.600 320 259

Dart PRO1 205cc LS1 Heads Intake Valve 2.020" Exhaust Valve 1.600"
Lift Intake Exhaust
.200 156 109
.300 215 154
.400 258 187
.500 290 205
.550 296 210

Patriot Performance LS6 Style Stage II Heads Intake valve 2.020" Exhaust Valve 1.570"
They also have a 2.055"/1.57" available but no flow numbers, probably better flow on the intake side
Lift Intake Exhaust
.200 140 124
.300 202 160
.400 244 196
.500 280 220
.550 291 226
.600 304 229

Edelbrock 202cc Intake valve 2.020" Exhaust Valve 1.57"
Lift Intake Exhaust
.200 141 115
.300 200 162
.400 245 196
.500 282 208
.550 294 213
.600 300 217

 

Also will combustion chamber size affect the flow results? Do the different size valves effect anything after the flow numbers, or do they contribute to the flow numbers already recorded?

 

The TFS are the hot ticket right now, and you can see why. Runners are slightly bigger than AFR 205 (215cc), intake flow is correspondingly slightly better, but the exhaust flow is significantly better. Pick the right cam to go with those heads, and you can reach and surpass 500rwhp on the stock bottom end with all the extra bolt-ons. (FAST90/90, water pump, good headers, etc.)

 

Combustion chamber size will affect your motor's compression ratio, and thus power.

 

If you wanted edlebrock, TSP sells "terminator' heads which are modified edlebrock heads, with 200cc intake runners.

 

Ported ls6 heads, no matter what peak numbers they may be able to attain, are inferior in the lower rpm ranges to aftermarket head designs like AFR or TFS. They achieve their flow through very large intake runners, much larger than 205 or 215cc, which hurts velocity.

If on a budget, I would go with the Darts over ls6 heads. If money is not an issue, TFS or AFR without a doubt. Whenever I change heads I plan on running AFR 225 small bore heads or the TFS 215cc heads, provided I stay with the stock displacement.

 

What's $1000 between heads? I was just trying to weigh whether it's worth the extra $1000 in heads versus the amount of gains to be had from them. Plus I figure this thread could help other people out who are looking at heads. Both seem to be about $2400, but the TFS already come with dual spring titanium retainers good till .650", the AFR's don't.

Has AFR made any 215cc's or can they? Tony could jump on here if he sees this thread. I imagine they would flow better than the TFS's if they had. And the Spring upgrade for the AFR's is only $100, so the price difference would be insignificant.

If AFR makes the small bore 225's, then this would seem to be the way to go, as even the 205's do flow close to the 215's down low. Are these the same price? Special Order?

 

I know that, but it has no effect on flow numbers correct?

 

Tony's on vacation until early next month (back east). It is definitely a cost trade-off. I bought the Darts when they first came out but really wanted the AFR's. I knew I left power on the table with the decision. This winter, I plan to upgrade from the Darts to the AFR's. Darts are "as cast" and are a nice head with good parts, but I believe you won't make as much power with them compared to a good CNC head like the AFR. Bottom line is you can't go wrong with the AFR head, unless your budget doesn't allow for it. I like messing with my car so swapping out the heads in the spring will be part adventure as well

 

The AFR's had been my original plan. Seems like the AFR's or TFS is the way to go.

 

Are the TFS heads legal here in SoCal?

 

I'm not sure, I know the AFR's are.