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This is a subject that isn't talked about a lot. I'm just finishing my cylinder heads and would like to see what others are doing in this area. I started with stock factory heads, pocket ported the intakes and polished the exhaust ports. I purchased Ferrea valves that are larger than the originals. Stocks were 2.08in/1.74ex new valves are 2.19in/1.90ex. I'm sending them off next week for new silicon bronze guides, new seats, and a three angle cut. If anyone has done this in the past, what gains did you get? I'm going to take pictures before I send them off and will post later.
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I am making 40hp more than the rated 375hp 440 with a stock bottom end. 275,000 mile stock cast pistons, 8.5-1, reringed with a top fuel hone. I ported the bowl after I had the valves replaced with the larger size stainless. Heads are 915 castings. I couldn't belive how good it ran. I just took parts I had laying around the garage and put a motor together. I was getting married and money was tight.
906, and 915 are pretty good heads, 452's are ok.
I think the 426 heads are better than 906 and 915. I hope you didn't port those.
Brian
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I did it to my BBC last year and I will say it makes a noticeable difference, no idea how much. If you put in new seats they should be blended back into the chamber and ports & make sure you CC them when youre done. Also try to get some old valves that you can use to cover the seats up with when youre doing the chamber work. After youve done youre blending work then send them in for the final valve job. Did you do port matching on the intake & exhaust where needed also?
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a few years back i loaned the boat to a friend and he ran it way too cold and dropped a few valve seats. so i found another set of heads (455 olds) and decided to do just a little porting to em. i gained about 300-400 rpm. the entire rpm range was much better.:D good luck...
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I went to from a stock 906 head to a fully ported stageVI head and there was a huge difference. The motor pulls way harder than before.
I wonder how it will pull with this 8-71 that was ordered?:rolleyes:
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I would have put a bigger intake valve in and left the stock sized exhaust valve in it, but then thats just me.:rolleyes:
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I have 2 sets of 906's, 1 set of 346's, 1 set of 915's, and 2 sets of 452's. I went with the 452's with I stamp because those are the beefest heads for porting as stated in Mopar muscle magizine. They all share around the same cc volume except for the 915's. I was always told with valves "what goes in must come out" if thats true, who knows, but it makes sense. So far all the pocket pinch is gone, and the exhaust ports are polished to a nice shine. I still have to do the gasket match. I saved the old valley pan for a pattern. And no porting to the Max wedge heads, because I never had them, but wish I did.:D
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Originally posted by Mopar426
I have 2 sets of 906's, 1 set of 346's, 1 set of 915's, and 2 sets of 452's. I went with the 452's with I stamp because those are the beefest heads for porting as stated in Mopar muscle magizine. They all share around the same cc volume except for the 915's. I was always told with valves "what goes in must come out" if thats true, who knows, but it makes sense. So far all the pocket pinch is gone, and the exhaust ports are polished to a nice shine. I still have to do the gasket match. I saved the old valley pan for a pattern. And no porting to the Max wedge heads, because I never had them, but wish I did.:D
Now that makes me feel better. Thanks.
If you want to make a fellow boater happy, I need another set of 915s, do you want to sell them? If so let me know about their condition and how much you want.
Brian
