Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by JoseK5, Apr 9, 2002.
Anyone running AFR 180cc heads on 383? How do they compare to the vortecs?
really depends on your combo and where you are trying to make power. Also you really need to have the AFR's done up with at least a 3 angle valve job. No such thing as an "outta the box head" with aftermarkets, even if they say cnc ported blah blah blah. If you are just going for a motor under 4500 rpm, save the cash and go for the vortecs. They flow gangbusters in the mid rpm range. The AFR's will do better in the upper rpm range and flow similarly in the mid rpm ranges. The downside is the cost of intake and if you have to deal with the EGR setup. If you want to avoid those issues, a set of World Torquer SR's can be worked to flow gangbuster and will still accept the early sbc style or 87 and up style intake. They also are offered with 2.02/1.60 valves... a bit bigger then the vortecs for an added jump in the upper rpms if you need it.
I had a set of 180 AFR's on my other blazer that was stolen. Those heads made some serious torque and I also gained 2 MPG. They do come in either early or late style valve cover and intake bolt patterns. They are 50 state smog approved. They do come 100% CNC ported, combustion chambers, intake runners, exhaust runners. CHP did a big flow test comparison of about 38 different small block chevy heads catagorizing them by intake CC's and they out flowed almost everything they tested, even some of the bigger heads. I was very very pleased with them. I would not even think of running a vortec head. And yes they were on a 383 chevy.
Scott...I won't take anything away from the top notch AFR heads, cause they are nice heads and well designed, but these so called CNC ported from AFR is a bunch of whoeie. WTF is CNC ported??? CNC machined I understand but ported? The whole reason for minor porting is to basically fix machine error or variances. AFR says these will flow 250 on the intake side right out of the box(.050 lift)... I'm not sure what kinda testing they are doing, but the flow bench most of the guys I hang with have been going to flowed 190 AFR's at 185 at .050 lift. These are the heads that my friends Andy has on his 400. Plus if you rip these heads apart or order then bare you can look in and see that they need clean up.
Plus look who advertises in CHP... AFR, Brodix, Edelbrock... etc. None of these heads really blew anyone away. I love CHP for look at cars and some of the mechanical engine fundimental stuff is nice, but their build ups and comparisions are kinda BS. After all they are bias to their big advertisers, which AFR is a big one. Did you hear about the engine buildup last year by one of the mags that they found opps... these heads weren't out of the box... they have a stage III port job /forums/images/icons/shocked.gif Big performance difference from stock.
I don't want to start anything, but you can't believe what the advertisers and mags tell you... they are in it for the money more then anything else. Unfortunetly there are a lot of people out there who aren't experts and they trust these sources for information. If you really want info... talk to your local NHRA,IHRA, NMCA racers and the good race motor builders or shops in your area.
BTW... the one big gain is the AFR's have larger valves which will help flow a bit, but you could look into camel humps w/ 2.02/1.60 valves or World's heads for a cheaper price. I really think you have to look at your application and then look at the 500 or so dollar difference in price and compare it the the real world power you are gonna get
Thanks for the input guys, I think I will go with the cheaper vortech since my 383 will not see any RPMs higher than 5000+, and also i think the vortecs with a bit of prep work and their newer design will be adequate. I agree though that some other heads might be better but I think one gets more value for the dollar with the vortecs.
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