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Newb here, looking to turn a 502 into a 540, have questions

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Old 03-30-2021, 08:05 AM
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Originally Posted by ICDEDPPL
This one post wonder is really involved in this discussion.. hasn`t been back since he made the post .
Still here, got to start tear down this past sunday, to stay within budget were looking at just making it a 509 and then converting to roller cam. Bore was stock, supprised it had tiny domes in it already, figured stock would have been flat tops or even dished, heads are 188 castings, deffinantley going more modern than them.
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Old 03-30-2021, 08:44 AM
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Welcome back.

If I were you, I’d change the rods and pistons. For the cost of a rebuild on the rods, you can get better rods for just a little more money. And the pistons... they are a JE/SRP piece made for GM that use a metric ring pack that is expensive and allows some oil leakage into the combustion chamber. They are hard to find. A replacement set of pistons can be had for around $600 and rings for another $100 or so, both from JE/SRP.

The above is the route I took with mine.

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Old 03-30-2021, 09:13 AM
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Originally Posted by GPM
Just an opinion, go with the 540, boats like cubic inch. Scat, Lunati, Compstar, forged crank kit, 320 or so cc heads, 8 degree split on the cam, 112 lsa, air gap dual plane will make more torque and just as much HP as the single plane but in the RPM where you will use it.
how is this for the cam?, it fits your split and lsa criteria, melling 22472 duration @.050 237/245 lift .626/.639 lsa-112, I can get it new for under $200 and yes its a roller cam.

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Old 03-30-2021, 03:21 PM
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I would think that's a little small for a 540, you are probably better off calling someone like Bullet Cams for advice. I mostly run solid rollers.
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Old 03-30-2021, 03:37 PM
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Before you can select a cam, you really need to know what you're doing for heads.
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Old 03-30-2021, 04:45 PM
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Originally Posted by tchapps88
how is this for the cam?, it fits your split and lsa criteria, melling 22472 duration @.050 237/245 lift .626/.639 lsa-112, I can get it new for under $200 and yes its a roller cam.
For that price is it a cast cam ? OE GM amd Merc use steel cams even for black motors, not just blue.
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Old 03-31-2021, 12:40 AM
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Originally Posted by tchapps88
Still here, got to start tear down this past sunday, to stay within budget were looking at just making it a 509 and then converting to roller cam. Bore was stock, supprised it had tiny domes in it already, figured stock would have been flat tops or even dished, heads are 188 castings, deffinantley going more modern than them.
I think you may be happier with that in the end. The reason I mentioned the Bravo is a 509 puts down the power a little more up top when the drive has had a chance to unbury itself instead of driving that 540 torque to it while it’s still mired deep. I’m just an Internet shade tree hack but that’s my understanding of it when I considered bigger power.
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Old 03-31-2021, 01:32 AM
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I'm going with the stroker 540, I figured that I can control the throttle to lessen the stress on the outdrive down low but torque × rpm is hp so ill let it sing on the top end. I purposely chose a mild comp cams extreme marine cam to avoid issues with reversion.
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Old 03-31-2021, 03:06 PM
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Originally Posted by Baja Rooster
I think you may be happier with that in the end. The reason I mentioned the Bravo is a 509 puts down the power a little more up top when the drive has had a chance to unbury itself instead of driving that 540 torque to it while it’s still mired deep. I’m just an Internet shade tree hack but that’s my understanding of it when I considered bigger power.
It's all in how you run it,
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Old 03-31-2021, 05:06 PM
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Originally Posted by TomZ
Welcome back.

If I were you, I’d change the rods and pistons. For the cost of a rebuild on the rods, you can get better rods for just a little more money. And the pistons... they are a JE/SRP piece made for GM that use a metric ring pack that is expensive and allows some oil leakage into the combustion chamber. They are hard to find. A replacement set of pistons can be had for around $600 and rings for another $100 or so, both from JE/SRP.

The above is the route I took with mine.
pretty sure the mkiv bowtie block 502’s had standard rings
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