575sci 502 to 540
12-06-2012 | 07:04 PM
#11
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From: chicago
Depending on how the pistons and crank counterweight are cut, they may or may not clear the crank counterweights with a stock (6.135) length rod. Usually, they won't clear, so you need to go to a 6.385 or 6.535 rod with a 4.25" crank. You would also have a less than desirable rod angle(1.44) with a 6.135 rod and 4.25 crank. If you use the longer rod, then you will have to change the pistons because the compression height will not be correct. Most would use a 6.385 rod with the 4.25" crank.
Eddie
Eddie
something to consider also. If your $hit's in good shape, and its power you seek, freshen it up, install some good headgaskets, a superchiller, a hyd roller cam, and up the boost a bit. If that doesnt sound like enough, sell those 256 blowers and bolt on some whipples, or 8-71s. You'll find more power there than just going up 35-40CI, for around the same money. Because at 540CI, your blowers will be smaller than they are now.
Last edited by MILD THUNDER; 12-06-2012 at 07:07 PM.
12-06-2012 | 07:04 PM
#12
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From: Naples Fl
My Potter built 540 is the short deck block .030 over with the 4.25 crank and 6.385 rod, this is what most do so you are starting out with a fresh bore, the right pistons, and is a totally fresh short block.
12-06-2012 | 08:07 PM
#13
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From: Midwest & T-Rock
12-06-2012 | 09:41 PM
#15
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From: MI
+1.
something to consider also. If your $hit's in good shape, and its power you seek, freshen it up, install some good headgaskets, a superchiller, a hyd roller cam, and up the boost a bit. If that doesnt sound like enough, sell those 256 blowers and bolt on some whipples, or 8-71s. You'll find more power there than just going up 35-40CI, for around the same money. Because at 540CI, your blowers will be smaller than they are now.
something to consider also. If your $hit's in good shape, and its power you seek, freshen it up, install some good headgaskets, a superchiller, a hyd roller cam, and up the boost a bit. If that doesnt sound like enough, sell those 256 blowers and bolt on some whipples, or 8-71s. You'll find more power there than just going up 35-40CI, for around the same money. Because at 540CI, your blowers will be smaller than they are now.
Last edited by JRider; 12-07-2012 at 05:45 AM.
12-07-2012 | 11:36 AM
#17
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From: chicago
I failed to inform that I already have upgraded the blower to an 871 littlefield and a whipple low pro cooler. The motor is out right now and my gears are turning. Maybe it is time to just upgrade the cam to a hyd roller...going to have everything inspected and make some decisions. Wouldn't mind going to some aluminum heads either.
12-08-2012 | 07:05 AM
#19
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From: Pompano Beach FL, USA
Just a thought - if your 502 is running sell the long block and start over from scratch.
What's left of your old engine if you replace the crank, rods, pistons & heads?
What's left of your old engine if you replace the crank, rods, pistons & heads?
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www.mercruiserparts.com
www.go-fast.com
www.bammarine.com
www.cyborgtransmissions.com
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12-08-2012 | 08:35 AM
#20
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From: MI
The biggest decision I have to make is heads. I cannot go with raised exhaust port heads due to my hatch clearance with the etops. That limits my selection of heads. I considered going with the edelbrock marine heads due to cost and hatch clearance...OR I could have Valako port my stockers on the exhaust side. Any input in this catagory would be helpful. After choosing heads the cam is next.
