Hello,
So my earlier posts of an overheating 351w ended up being a cracked head. Looks like I worked em over too much when I had them at the shop. The engine only has about 40 hours on it. Magnafluxed them prior to the build, but they didn't stand up.
So now I am looking into a set of aftermarket heads but don't know what to go with. I want to stay away from the aluminum heads and stick with iron. Don't want to risk warping aluminum heads.
Cylinder Heads - summitracing.com
I was checking Summit and looks like they offer Dart and World Products Windsor (Jr & Sr). Any help picking out a good set would be appreciated. I am sure I am going to need at least cam specs and bore, what other info do I need to dig up to get the correct combustion chambers, valve sizing, etc. to stay at the 9.5+ compression? Will these work as well as my built heads? Will I be able to use my 1.6 full rollers on the new heads or do I need new rockers? Do I need to replace push rods, lifters, head bolts, etc. with so little use in the engine?
The bottom end is bored 030 with flat top pistons. The EFI is an Edelbrock MPI setup. I don't have the cam specs with me right now, they are in CO and I am in DC, but it's a strong RV cam.
I have seen a couple reports that the World Products heads produce decent power gains even with the stock EFI intake. I have a set of Dart Iron Eagles on order(haven't got them yet), and using actual head flow data this is what they look like in Desktop Dyno. These heads flow close to what the AFR185 heads do, which is considerably better than the WP heads. Flow data here... http://farm3.static.flickr.com/2089/...c89acd.jpg?v=0
Considering the thousands of sets in use every day for everything from daily drivers to full race use, you should set aside any worries about warping aluminum heads and buy some AFR165's. The guy who built my engine has dyno tested them all and said the AFR's blow away everything else. I quizzed him about flow numbers, etc.; he kind of laughed and said the dyno doesn't lie - AFR's outperform anything else out there by a wide margin.
Naturally, I ignored his advice and bought some FRPP X303 heads. But only because I got an awesome deal on them from a local speed shop. The X303 heads are about the same price as the heads you linked to at Summit, FWIW.
And from that link it looks like the only heads that would ship anytime soon are the World Sr. heads. Since you won't be spinning an engine with an RV cam much past 5,000 I'd stick with smaller runners to keep your low end response.
I'd invest in a set of ARP head bolts, but the rest of your parts should be okay.
Agreed.. the AFR heads are proven performers. What I have learned about the Dart heads is that they use very similar molds for both the aluminum and cast iron versions, and both versions get the same CNC port work, so there should be no significant performance difference between them. I'll have to find a dyno when I get this thing together and get some on-the-ground numbers, then we'll know.
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