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Old 11-15-2002, 06:59 PM
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Post question on valve sizes

What difference would there be in torque and Hp, between 1.94/1.50 valves and 2.02/1.60 valves in a 350 SBC motor with fairly stock heads? If you was to step up to the 2.02/1.60 would you loose very much TQ? Just a thought!!

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Old 11-15-2002, 08:51 PM
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installing the big valves in the stock heads is a good example of an expensive waste of time and money. if you are not turning the motor over 5500 you are not using the valve area and at low speeds you loose some throttle response and torque because of the valve area.
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Old 11-16-2002, 03:05 AM
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Amen to the previous post, in most cases that's always something that seems to be on the "to do" list, when the money could buy some real usable power.
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Old 11-16-2002, 05:39 AM
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The reason I was asking is, that I already have a pair if 487X heads with the 2.02/1.60 valves in them, with a mild port and polish that was done a while back. I was trying to decide whether to use these heads or try and find some with 1.94/1.50 valves. Thanks for the info.
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Old 11-16-2002, 06:02 AM
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I have never found larger valves to hurt power, but without the added valve lift and duration to make use of the area no horsepower boost either. Use what you got it won't hurt and you have the larger valves if you decide to upgrade later.
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Old 11-16-2002, 08:07 AM
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My cam has a duration of 278, 222 duration @ 50 and .467 lift with a 110 lobe separation. Will this work good with those heads??
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Old 11-16-2002, 03:02 PM
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If not, does anyone have a set of 487 heads with 1.94/1.50 valves, or do you know where I can get a pair??
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Old 11-16-2002, 04:47 PM
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I think what Bob is saying is don't wase your time having bigger ones installed. IF you do so without unshrouding the valve you will not be happy. It will produce less hp and tq and any rpm range. Use the heads if you have them. I would go with a modern cam grind if you don't have this one purchased already, jmo. Good luck, Ryan
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Old 11-16-2002, 07:53 PM
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The cam is already in the motor. Will these heads work good with that cam good enough to get a fair amount of power?? I hate to have to buy another pair of heads, when these might work ok.
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Old 11-16-2002, 08:07 PM
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Bolt 'em on. You already have the cam. It's a fairly warm grind so it should work on the top end with your heads. I ran a pair of camel hump 2.02's in a 56 hardtop with several style transmissions, auto and stick. Depends some on what you are poking this thing in and the trans, rear gear, use, etc. Haven't seen anything on any oftrhat and it's really important.
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Old 11-16-2002, 09:31 PM
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Put um on,or wait no! You really want to trade me for my 993s.Thats what you wanna do!!!You really wanna trade me.Repeat this several times befor bed then in the morninfg you'll see the light and trade me.
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Old 11-17-2002, 08:19 AM
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LOL.....Very funny! You know the 487X is a better head. Now, why would I trade you for these?? You would be getting the better deal. I have heard from a couple places that the 487 and 487X heads came with hardened valve seats. Does anyone know if this is true?? Just a thought!! Thanks!
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Old 11-17-2002, 04:01 PM
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depends on the casting date anything after 1974 is hardened. most of the x heads aren't.
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Old 11-17-2002, 04:25 PM
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I know they are heavy duty castings, but what would happen if they didn't have hardened valve seats and they were used with unleaded gas? They came off of a 283 that was bored .060 over with domed pistons. The 283 always ran unleaded gas. So, I assume they have hardened seats.
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Old 11-17-2002, 11:01 PM
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OK fine!!!Your not getin my 993s now!!

I've seen double humps without hardened seats used w/ unleaded.I don't think it is really all that bad.I'd just dump in a bottle of lead substitute when you fill up.
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