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Discussion Starter #1
Been taking me forever to get started, but I'm finally starting to put something together. A 489, 4.25 stroke. I have the Moroso pan # 20403. I know lotta others run this same pan. So with it having windage tray, crank scraper, and anti climb lip, is it worth putting a small cover over the oil pump sump? Cover as much as I can and still get the pan on it? Be something like the picture attached. Mainly street deal, little strip maybe. Prolly looking at 6-6500 max deal, but you just never know...thx
697122
 

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I made one similar to that for my 20403 pan. I'll dig up some photos and post them later. It's going on a 565 fwiw (4.6" bore, 4.25" stroke).
 

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Here are two photos. The little blocks of wood (0.225" thick) between the pan rail and angle iron main cap mount were used to simulate the depth of the rear main register in the block plus the gasket thickness.
 

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Those pans definitely need help over 6500. I have seen many times where the oil pressure starts to drop off with the 403 and 408 pans with a 4.25 stroke crank. Never enough to hurt anything but enough to know that something is not right in oil pan land.
 

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Discussion Starter #6
Thx guys.

Dave, it looks like ur shield stays with the pump when u pull the pan. Is that right?
 

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Yes. I'll flip it over and take a pic tomorrow.
 
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I have that pan on a 489 (Summit wht box) and like Ray said the oil pres. dropped at higher rpm on the dyno, shop owner said he didn't think the engine liked the pan, dyno graph with oil pres. is in my album
 

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Discussion Starter #9
Agree. I did some reading on this pan, and although lots of people run it, there are some that say the same as you guys are saying, that over 6500, psi begins to drop. I wonder if the oil in the sump is being splashed so much that it begins to aerate and cause this to happen. Also wondering if the cover, as I showed in the first post, and like what Dave has posted above, would fix this problem.
I'm not overly concerned about it, as I don't plan over 6500, and if it is, not much over. But while I'm messing with it, maybe I can correct it so there isn't an issue. Putting a sump cover on it is simple enough.
 

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I use the same pan and with a 4.375 in,crankshaft.When I put it on the engine dyno we found that it was very particular regarding the oil level.
Too much and the oil pressure dropped at 6500-7000 RPM.After a bit of experimenting we found that 5 1/2 quarts was the sweet spot.
Guy
 

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I believe I have the same pan. It would be really nice if it had a relief to remove the oil filter with the headers still installed.
I had to use a remote oil filter kit to clear the kick out sump and the headers.
Guy
 

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I'll have to look back in part #s because my pan dont have a kick out, we also started with 5 qrts then 6 and made no difference
 

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mines the SUM-G3605 I believe Moroso makes it but maybe not the same inside as yours, looks like it to me though
 

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The only thing I can't say is IF the rear of the pan is where the issue is. I believe the issue is at the front of the pan with the stock front half and fitting in a stock chassis with the 4.25 crank. I ran the 21049 pan and 22187 pump in my car finally and the issue disappeared.
 

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Discussion Starter #16
Thanks for everyone's input on this. I think I'll most likely make some kinda sump cover, and go with it, with attention to oil level once I get that far. Like I said, mainly street car under 6500 most of the time. If I was racing in the 7000 and over range, I'd do something different.
I used to run Canton pans on my circle track engines, but they were dry sump engines turning about 8600.
 

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Thx guys.

Dave, it looks like ur shield stays with the pump when u pull the pan. Is that right?
Here's some photos of the sump shield and pump on the engine. It's a 4.6" bore x 4.25" stroke (565) and hopefully the Callies Magnum crank with profiled counter weights will minimize windage. Driver's side kick out was modified to make oil filter removal easier.
 

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if you see that pressure drop at 6500 try draining a quart out of it and try again. windage is a biotch.

I also thank you for your service Mt Bates. nice looking block there.
 

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Dave musta done real good work for the AirForce is all I can say. I'm with Tom. Nice work Mr Bates!
 
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