My new AFR heads
#13
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Originally posted by PatriYacht
My new AFR 335 CNC heads came in the mail today. What a treat! I feel like a kid at Christmas. These things are jewel like in their finish, l
My new AFR 335 CNC heads came in the mail today. What a treat! I feel like a kid at Christmas. These things are jewel like in their finish, l
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#14
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Join Date: Jun 2003
Location: Park Ridge, IL/ Sheridan Beach, IN
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I used the AFR315 CNC heads on a pair of Dart 540's I built over the winter for my boat. With Crane 741 cams, 9:1 compression, Victor Jr single planes with Holley 850 cfm carbs, they made between 690 and 695 hp @ 5700rpm and 670 tq @ 4600rpm on a Superflow 600 dynamometer. That was with headers though, so I'm figuring somewhere around 650hp with Stainless Marine manifolds.
AFR's BBC heads are really nice castings, much better than some of their SBC castings I have used for automotive apps. The only issue we had was one of the heads required us to mix and match guideplates from COMP, Brodix, and Manley to get everything lined up properly. We were able to use all COMP on the other 3 heads, and the one that needed the mix & match plates wasn't really that bad and it probably would have been fine, but we had the time and the plates to get it perfect.
Also, we flowbenched the cylinder heads and they actually exceeded AFR's published flow numbers for those heads, but we did use better valves (Del West) and we added an additional 30* backcut for better low lift flow. At some lifts we exceeded AFR's claims by almost 20cfm.
The recommended Victor Jr manifold was a perfect port match and we didn't have to do any matching.
I test fitted the Stainless Marine manfiolds on the cylinder heads and the ports match up very nicely and there is no interference issues, even with head studs.
AFR's BBC heads are really nice castings, much better than some of their SBC castings I have used for automotive apps. The only issue we had was one of the heads required us to mix and match guideplates from COMP, Brodix, and Manley to get everything lined up properly. We were able to use all COMP on the other 3 heads, and the one that needed the mix & match plates wasn't really that bad and it probably would have been fine, but we had the time and the plates to get it perfect.
Also, we flowbenched the cylinder heads and they actually exceeded AFR's published flow numbers for those heads, but we did use better valves (Del West) and we added an additional 30* backcut for better low lift flow. At some lifts we exceeded AFR's claims by almost 20cfm.
The recommended Victor Jr manifold was a perfect port match and we didn't have to do any matching.
I test fitted the Stainless Marine manfiolds on the cylinder heads and the ports match up very nicely and there is no interference issues, even with head studs.
#15
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I haven't had a chance to match up the exaust or intake manifolds yet. The intake locations are supposeded to be stock, so with some port matching I should be alright. The intake is a Merlin single plane with a holley 1050. I'm hoping to keep the Merlin because it has the longest runners of any I've seen. It's really tall. Kind of like a semi tunnel ram. The exaust is a question. While the port and bolt pattern is standard Chevy, the entire head is rolled a couple degrees and the ports may be higher on the head. I have a little play where the tailpipes go through the transom. Hope it's enough.
AFR has a website www.airflowresearch.com. Jack also backcut the valves and installed Isky springs. The valves are Ferria(sp).
AFR has a website www.airflowresearch.com. Jack also backcut the valves and installed Isky springs. The valves are Ferria(sp).
Last edited by PatriYacht; 03-17-2004 at 09:41 AM.
#16
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Monty:
Love hearing about that engine, it sounds perfect. Good point about the head studs. I had to change the head bolts under the exhaust ports with the engines in the boat, because I didn't trial fit the exhaust manifolds.
PatriYacht: How high is the Merlin intake? From block to carb flange a Dart is just over 6".
Love hearing about that engine, it sounds perfect. Good point about the head studs. I had to change the head bolts under the exhaust ports with the engines in the boat, because I didn't trial fit the exhaust manifolds.
PatriYacht: How high is the Merlin intake? From block to carb flange a Dart is just over 6".
#17
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Ian you should have struck a deal with Kaama for his 540's they made 699 hp at 5600.....
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#18
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Originally posted by tomcat
Monty:
Love hearing about that engine, it sounds perfect. Good point about the head studs. I had to change the head bolts under the exhaust ports with the engines in the boat, because I didn't trial fit the exhaust manifolds.
PatriYacht: How high is the Merlin intake? From block to carb flange a Dart is just over 6".
Monty:
Love hearing about that engine, it sounds perfect. Good point about the head studs. I had to change the head bolts under the exhaust ports with the engines in the boat, because I didn't trial fit the exhaust manifolds.
PatriYacht: How high is the Merlin intake? From block to carb flange a Dart is just over 6".