Do bigger valves need bigger seats???
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From: Mount Dora, Fla
Do bigger valves need bigger seats??? I've got a set of Absolute Speed 5.3L heads with 2.02 and 1.57 valves and would like to go to 2.08 and 1.60 valves. Do the seats need to be changed or bored out or what? I'm moving up to a 408 and there is no way I can spend extra $ for a good set of heads now, so I need to max out the heads I've got. I hope new Manley or Ferrea valves and a valve job isn't over like $500. Does that sound about right?
For a good valve job and valves alone, it'll be close to $500. You could probably get a valve job for cheaper, but it sounds like you're looking for improved flow.
Anyway, I believe a 1.57 is the biggest you can fit on the stock exhaust seat, but I'm not sure on the intake diameter. Just make sure the shop working on your heads is up to the task. Ask to see some of their work. I've seen some heads ruined by shops attempting to change seats.
Ben T.
Anyway, I believe a 1.57 is the biggest you can fit on the stock exhaust seat, but I'm not sure on the intake diameter. Just make sure the shop working on your heads is up to the task. Ask to see some of their work. I've seen some heads ruined by shops attempting to change seats.
Ben T.
Last edited by Studytime; Nov 15, 2006 at 11:14 PM.
The valves you currently have are about the largest valves you can machine onto the factory seats. I'm afraid it's going to cost a good bit more than $500 to do the machine work to put larger seats in, blend the new valve seats to the valve bowls and supply the valves. Add in the hot tank, blast cleaning and reassembly charges and it can increase the cost pretty quickly.
Richard
Richard
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Thanks for your response Richard. You were on my call list when I take the heads off Thanksgiving weekend. The way I was looking at it was Manley Racemaster valves or Ferrea are about $10 each for $160, seats are about $3 each for $45. Assuming the guides are OK I figured $300 for the valve job and putting things back together. I already have TSP springs retainers and shims. I CCed the runners acouple of years ago and the intakes were hogged out to like 235cc so they should be good for 400+ci. The heads are 862 castings.I would really appreciate further input.
Last edited by bigdsz; Nov 15, 2006 at 11:46 PM.
More than likely the valve guides are going to be ok. Your right inline on the cost of the valves, however replacing the pressed in valve seats is going to run $18.00 per seat for parts and labor. Have the heads actually been flow tested as they are currently? If the airflow is respectable, then sharpen up the valve job, and put 'em on your stroker engine and enjoy.
Feel free to call us anytime to discuss your options.
Richard
Feel free to call us anytime to discuss your options.
Richard
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Jay liked to hog out the runners like Lingenfelter, as opposed to AFR who likes narrow runners with greater velocity. At .500 flow was 293 and 216 and at .600 flow was 313 and 227. The dilemma is that, as you know, there are so many inexpensive heads on the market now, my AS 5.3's aren't worth much and I hate to put more good money after bad in them. So I don't know what to do. Help??? When you say sharpen up the valve job I guess that means keeping the 2.02/1.57 valves. Can't the existing seats be messaged a little, bored, so that I could get better flow and go to maybe a 2.05/1.60??
Last edited by bigdsz; Nov 16, 2006 at 01:31 AM.
i had new seats installed and have 2.055/1.60 manley valves machined in my 241's. hot tanked and blast cleaning, i have $540 in them parts and labor, but they were also bare when i took them to the shop and i assembled them myself.
