|07-21-2006 02:32 PM|
I have always found AFR's to be well within reason on the flow bench, up to their 220 runner 23 degree heads. Have not seen or done any heads larger than this, like their 227, 215 RR or big block stuff.
Brodix is well within reason as is Edelbrock on the flow bench versus advertised. Canfields that have been purchased assembled through Competition Products sucked but bare are nice heads. I have seen their fully ported 220 runner castings flow amazing numbers on the bench.
Those really cheap china knockoff that are out there are aweful. They flow squat at low lift then at .550 they spit out 260 or so. But if the cam only lifts the valve to .500 a customer is better off with a Vortec.
We have used lot's and lot's of Dart heads over the years as they are legal for our race classes. They typically do what's advertised as well. Your right Jay, we'd love to have an option on the SR head, it's suckey for a race class head. It's silly to not allow some better heads in some of these classes as everyone knows the inordiante amount of time and labor we go through to "make these heads work" within the confines of the "must be stock" rules.
|07-21-2006 12:26 PM|
Jay i'll shoot you a pm..
|07-21-2006 12:10 PM|
|1bad18||advertised numbers only mean jack if you are fixturing and testing the cylinder head in the same exact manner that was used to obtain the advertised data... and honestly, you'd want to test with a fixture very similar in dimension to the engine you are putting it on in order to achieve any meaningful data for your application... unfortunately tou rarely see the "important" information passed on with advertised airflow data... other than the depression it was run at... so just take it all with a grain of salt... gotta love fluid dynamics and creative marketing|
|07-21-2006 11:37 AM|
Not to change the subject of this thread, but you've got me curious. Can you give me and some sort of an example of what kind of numbers you where getting in difference to AFR's numbers when you flowed them. I've only had a few sets across the bench, but they where all cnc'd or someone had been in there doing some work. But must say the cnc'd ones where really close, usually within 4cfm at every lift point.
I hear what your saying, I dont know how many times I've flowed a head and checked it against their advertised numbers and thought "false advertising". I was a little impressed with the Pro1 180's myself. I recently did a little cleanup work on a set of Canfield's that I was impressed with out of the box, but have found that usually you can take everything they adv. up to about .400 and sometimes .500 and throw it out the window.
Another head that impresses me for what it is, is Dart's SS head. I had to check my set up twice because I couldnt believe a head designed to be a stock replacement would be that good. I bet alot of the dirt track guys would love to get these okay'd for there rules and get away from the World SR's.
|07-21-2006 07:10 AM|
One thing to think about,,, the amount of air that a head moves is only part of the story....There is a bunch of other factors that decide if the head works or not...
I have no testing on the smaller AFR heads but the bigger cnc'd heads are not that good IMO...Please don't buy in to the magazine and marketing hyp..any body that has a set of the AFR's on a bench knows what i am talking about.......
I personally think the track-1's would work with your combo, I personally have not had the track-1's on the bench yet but i understand they move "GOOD" air in the lower lift as well as the hight lift ranges... Maybe Rick can confirm that....
One of the best heads out there right now is the dart pro-1's.. They are priced nice and they work. Again maybe not the throw down numbers of some of the other heads but they move "GOOD" air...
|07-21-2006 05:51 AM|
|6426yy||I've heard nothing but good things about the AFR's and I think that a 180 intake runner would help the tunnel ram at slow engine speeds. The quote I got from Comp was with stock 991 heads so that is probably why their so mild on the cam spec's. I'll keep my eyes open for a deal on some good heads and keep you guys posted, thanks.|
|07-20-2006 10:58 AM|
If I may so bold, I would throw out some suggestions like AFR 180 or 190's, Canfield 195, or Dart pro 1 180's. All have good air flow for the runner size which sould work very well with your combo.
A recent one I was just involved with is a 350 with the Canfields with the CNC combustion chamber, flat top pistons, small solid cam which was very simular to the 240-246 Comp, Weiand Team G intake and a 750. Made 470 hp and 475 ft.lbs and is a brute on the street.
|07-20-2006 08:57 AM|
|Rick WI||With the setup that you describe I'd not be afraid to use the Track 1. BUT, given your going up like that in duration get the lift into the .550 or above range. That's where the head will flow well.|
|07-20-2006 05:51 AM|
Thanks for the replies guys, I knew they were pretty large for say a 350, just wondering if they'd work on a weekend warrior. I'm looking at heads for my 355, I've got forged .100 dome TRW pistons and the lower end is a fresh 4 bolt main. Haven't bought cam or heads yet. I just picked up a Offy dual quad setup last night with 390 holleys so that is the intake I'm going to run.
I'm going to install this in my 82 S10 with a powerglide, 3200 converter, and 4.11 rear gears. I just want something to tinker on this winter so I'm trying to gather all my parts.
Any suggestions, Comp Cams suggested cam 12-250-3 240/246 duraton, 507/510 lift 110 LSA. Still waiting to hear from Lunati.
|07-20-2006 01:10 AM|
Rick's got it nailed. Here's my opinion why. Depending on how many cubic inches you've got, and your intended usage of the engine I.E. mainly street driven, street strip, weekend warrior etc. and the rpm range your plan on running, will all dictate what head is going to work best in your combination.
Cubic inches and rpm range are going to require a certain amount of airflow to make the power thats wanted. Airflow usually comes hand in hand with port volume. Get to big of a head on your motor, port volume wise, and the engine doesn't try to consume as much air through the heads. This means that the air that is moving through the ports isn't moving very fast (velocity).
Slow down the air to much and lots of bad things start to happen. The fuel will actually start to fall out of the air charge and collect on the bottom of the runner just to be poured into the chamber is large drops which as you know burns much slower that small very fine particles. You also give up some swirl speed. The speed of the air fuel mixture as it swirls about the cylinder starts to decay after the valve closes and the piston travels up towards the chamber. Once again giving opportunity for fuel to collect. Than as the plug sparks and ignites the mixture, because it is moving slower, it takes longer to move across the chamber/piston top and you end up with some lost cylinder pressure which is what the whole process is trying to produce to begin with.
Get a head that matches your CID, and rpms and the power can go up a fair amount, and the torque can really take off. Now if, as Rick said, you've got enough motor, than these are a great head, if you don't, a smaller head will actually make more overall power.
Sorry it was so long winded. Hope it helps.
|07-19-2006 08:32 PM|
|Rick WI||The track 1 works fine on the street assuming you have an engine that can take advantage of it. Nothing unusual about the valves, seat, guides.|
|07-19-2006 05:52 PM|
Track 1 heads race only. Why?
Is it because of the valve seats? Sound like killer heads.