head parts interchangability? |
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FUN-9C1
Senior Member Joined: January-29-2004 Location: Lakes Region NH Status: Offline Points: 206 |
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Posted: August-14-2009 at 1:39am |
Will the springs and rockers from my original '86 heads work on GT40P heads? The springs and rockers on the "cleaned and ready to assemble" GT40P heads I bought on ebay are covered in dirty oil, grime, mung, dirt and grit (don't buy anything from "larossfamily" on ebay- this is only one of 3 or 4 problems with this jerk) and I'd prefer to just use my nice and clean and probably less used ones from my old heads. How about valves while we're at it, are they interchangeable? They seem to be the same size but slightly different design on the valve head. One's cupped and one's flat. Can I use my old ones assuming I change ALL of them?
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'86 2001
'50 Century Imperial Sportsman |
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plumber538
Newbie Joined: October-09-2007 Location: Coventry , RI Status: Offline Points: 24 |
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I also bought a pair of GT40P heads on E-Bay for my 86 2001.I had the machine shop check them for cracks,and do a valve job on them,not knowing the story behind them I figured that was the way to go.Along with the heads I went with the Edelbrock manifold also.well worth the investment!!!
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mmartin
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21184 |
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I dont believe the valves are the same size, but you can swap the rockers over from your old heads.
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kapla
Grand Poobah Joined: March-27-2008 Location: BA, Argentina Status: Offline Points: 6148 |
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tim now I know why is good to pay the extra money on the heads from tristate!!! Haven't got the time to see them but my mate told they were excellent....
As for the rockers I will be using the old ones along with the pushrods... |
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<a href="">1992 ski nautique
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FUN-9C1
Senior Member Joined: January-29-2004 Location: Lakes Region NH Status: Offline Points: 206 |
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Well, after having my original (I assume) heads and the GT40Ps apart now, I've learned that everything but the int valves, exh valves in some cases (keep reading) and seals are interchangable. The springs measured the same height unloaded. Maybe somebody could tell me what the odds are that they would be different springs (diff pressure @ x compression)? I also learned that there are two different exh valve sizes on GT40P heads. Most seem to be 1.541, but the ones I bought have 1.450 ones. I think they're the same as my old heads exh, but not 100% sure. I wanted to buy new exh valves, but I couldn't find any info online and NAPA couldn't help me either, so I said screw it and bought reman from Tristate. I gotta say, my experience with them was my most pleasant business experiece in a long time. I just ordered them this morning, so I can't comment on the product yet, but based on my experience this AM I recommend them highly.
Anyway, I'd be curious to know if anybody has info on the 1.450 vs 1.541 heads. |
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'86 2001
'50 Century Imperial Sportsman |
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Gary S
Grand Poobah Joined: November-30-2006 Location: Illinois Status: Offline Points: 14096 |
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Sebastian, when you put it all together you'll have to check the lifter preload.You might need different pushrods. I did on my 302 block,but I had the old style rail rockers before on my old heads |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21184 |
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The stock valve size on the P's are 1.84/1.46. I believe 1.54 is a common size to overcut.
Its possible that the stock springs could be swapped over, but if you ever upgrade the cam, you want better ones in there that can handle more than .500 of lift. |
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kapla
Grand Poobah Joined: March-27-2008 Location: BA, Argentina Status: Offline Points: 6148 |
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tim didn´t want to hijack the post here, so please here is my concern on the push rods on my engine rebuilt post...
let me know your opinion.... btw is that the BFN on your avatar? push rods |
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<a href="">1992 ski nautique
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21184 |
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Kap, I replied in the other thread- youre confusing what I said about valve springs with the pushrods.
That is in fact our BFN. |
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kapla
Grand Poobah Joined: March-27-2008 Location: BA, Argentina Status: Offline Points: 6148 |
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thanks!!!
I´ll have to update my avatar with new pics when the resto is finished!! |
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<a href="">1992 ski nautique
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FUN-9C1
Senior Member Joined: January-29-2004 Location: Lakes Region NH Status: Offline Points: 206 |
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I hate to hijsck my own post- but to add to kapla's comment- that BFN sure is sweet. Love the graphics. I've always loved the slightly gaudy graphics on cars and boats of the '70s. I would love to add one of those to my collection of one someday.
Back to the valve question... |
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'86 2001
'50 Century Imperial Sportsman |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21184 |
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Ha, thanks Rob. We found this one about a month ago up on Sunapee. I think the late 70's graphics are cool too- theres nothing subtle about them! Its quite unlike the other CC's we've got... its a great addition to the fleet. |
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