articfriends

iTrader: (1)

Rob,i just looked at the flow test #'s,a dart pro 1 w/325 cc intake port as cast had a flow of 325cfm intake/223 exhaust at .600 lift,a set of out of the box as cast afr 305cc intake port heads have a flow of 363 intake/276 exhaust at .600,ABSOLUTELY NO COMPARISON.My world vr's have a flow of 313/207 at .600 !!!I guess next time i buy heads i will do more research!!!

Strip Poker 388

iTrader: (6)

Thats a lot of difference .

What about the flow at low lift #'s where the torque comes in to play?I wonder what the price difference is ?

Has any body compared the Eldebrock alum. heads???

Strip Poker 388

iTrader: (6)

Thats what TMP uses on most of there motors.must be a reason???

WETTE VETTE

The Dart CNC Pro 1's have an advertised flow slightly higher than the AFR CNC heads. The AFR's exhaust appear better, but they insist on running a pipe for some reason which gives them another 5 - 7 % on the bench. I chose 355 Dart Pro 1's for my NA 598 and it has very strong HP!! I agree that 600 HP for a 500 HP base is attainable, but it will be at high RPM's (like 6000) with good headers and probably a 1050 carb. This combo may not be real tame idling around the docks, but it can be done.

z.zuperboat

I'm not a head guy but are you talking iron or aluminum heads.My 540 made 625hp at 5700 with stock gm heads and I was told with the AFR,s it would have made about 700.Going aluminum you can bump the compression a point.I don't know what a point in compression is worth in HP.

articfriends

iTrader: (1)

Rob(strip poker)here is a more complete list of flow #'s,all of these #'s are as cast,i couldn't find ant cnc flow #'s on the dart pro 1's. Out of the box on a motor with .600 lift or less the afr's with a 305 cc intake port kick the dart pro1 a--,even if you compare the dart pro-1's w 345/cc intake port !!
AFR 305 as cast pro-1 325 pro-1 345 AFR-345
.200 163/135 141/93 141/106 141/135
.300 241/192 200/135 199/138 212/169
.400 300/237 251/170 254/173 279/219
.500 344/268 293/200 292/204 333/249
.600 367/284 325/223 323/224 372/272
.700 368/298 -------- 350/237 401/285
What these #'s tell you more than anything is a out of the box afr 305 is a exceptional casting,a out of the box afr 345 will only hurt your power unless your running a 700+ lift cam and the dart pro-1's MUST be ported to even keep up(i think they must be designed with the intention of only being run AFTER full porting),SMITTY

cobra marty

I was just looking on AFR's website and it gives the flow numbers. Interesting is that the best to me is the 315CNC head which out flows all their other heads-305as cast, 325as cast, 335CNC, and 345as cast. The 335cnc beats it at .600" 385 to 380 and the 345 only beats it at .700" 401 to 386.

When I buy a set of heads it will be the 315CNC.
They flow .2"=169, .3"=249, .4"=312, .5"=353, .6"=380, .7"=386

articfriends

iTrader: (1)

Marty,i know what you mean! These afr 305's as cast put my merlin's to shame,there would be such a big gain for me over my merlin vr's (average of 25% between in/ex) AND a exhaust balance at almost 80% vs. 65% that i'd almost skip the cnc job! The 325/345's offer almost nothing (except worse low lift flow!) I know what i'm getting next time!,Smitty

Wobble

gen4 509", pocket ported gm rect. heads, merlin marine intake port matched, 9.8-1 comp forged je and polydyned, 92 octane, ultradyne roller cam, holley 850 with proform main body, 580hp/580ft.ibs at 5300. over 500ft.lbs from 2900 rpm up. Would have liked better heads but this is best I could get on a budget.

WAGS382

Thanks for the feed back everyone, some good research going on here. I am still undecided on the 305 with cnc cambers or the 315 with complete cnc. I don't know if the 502 will benefit from the 315, What do you guys think? I can't wait to get these on the dyno and back in the boat to see what really happens. If any one else is serious please p.m. me and we can get some prices and get this going.