71 440 rod and main bearing, advice needed..

[flathead31coupe]

I know it has had to be covered here just cant find it... how do I know witch to use.. full 3/4 or 1/2 grooved bearings...the ones I took out were 1/2 grooved on the mains with a thrust flange dia of 3 9/16 = 3.5625 looking for the right bearings.... crank is 30/30...thanks

 

[Dubob]

What's your intended use ? Personally I'd run a 3/4 or half groove. Now this is just my thoughts but I've always viewed it as the 1/2 or 3/4 groove provides more surface area on the side that receives the most abuse. Probably other thoughts out there but that's mine.

 

[flathead31coupe]

What's your intended use ? Personally I'd run a 3/4 or half groove. Now this is just my thoughts but I've always viewed it as the 1/2 or 3/4 groove provides more surface area on the side that receives the most abuse. Probably other thoughts out there but that's mine.

daily driver/little fun when needed... summit offers the1/2 groove with a different size thrust ring than the 3/4 groove.. just tring to find the right ones.
Brand:Sealed Power

Manufacturer's Part Number:4924MA30

Part Type:Main Bearings

Product Line:Sealed Power MA Series Main Bearings

Summit Racing Part Number:SLP-4924MA30



UPC:614046632387

Bearing Usageerformance

Grooved Bearing:Yes

Groove Location:Upper and lower

Groove Style:1/2

Bearing Material:Bi-metal aluminum alloy, A-Series

Quantity:Sold as a set of 5.

Notes:Maximum outside diameter of thrust flange surface is 3.624 in. 1959-1960 383 cid. engines must verify flange OD before ordering. or,,,Brand:Sealed Power
Manufacturer's Part Number:5025MA30

Part Type:Main Bearings

Product Line:Sealed Power MA Series Main Bearings

Summit Racing Part Number:SLP-5025MA30



UPC:614046632615

Bearing Usageerformance

Grooved Bearing:Yes

Groove Location:Upper and lower

Groove Style:3/4

Bearing Material:Bi-metal aluminum alloy, A-Series

Quantity:Sold as a set of 5.

Notes:Maximum outside diameter of thrust flange surface is 3.930 in.

In-Store Pickup:Choose In-store pick-up (OH, GA, NV) on our web site.

 

[Dubob]

Being as yours is a 71 block it should use the smaller thrust bearing diameter.
The info below is from 440 source.com

Clevite 77 Main Bearing Info.

Because "B" (361/383/400) and "RB" (413/426/440) engines use different size main journals, each will have a different size main bearing. The "RB" uses a 2.750" main journal diameter, while the "B" uses a 2.625" so the two sizes are specific to each engine, however there is one additional difference...

From the beginning of production (when these engines were designed) in 1958 up until the 1973 model year the diameter of the thrust surface's outer edge (on the #3 bearing) will be approximately 3.470" for the "B" engine and 3.600" for the "RB" engine. Starting in the 1974 model year, this diameter was increased approximately .280 thousandths to 3.750" for the "B" engine and 3.880" for the "RB" in order the give the thrust surface more surface area. To allow the new larger bearings to fit, the machined recess area in the block webbing and the main cap in which the thrust bearing shells fit was increased an equal amount.

In the picture below, we have put two #3 thrust bearing main caps together. The one on the bottom is from an early block, and the one on top is from a late block. You can see the difference in the size of the machined recess area.



We refer to the pre '74 bearings as "Early" and the 1974 and later as "Late." It is possible to use the early (smaller) #3 bearing in all blocks, regardless of the year manufactured. For this reason, we offer bearings with the "Early" style thrust flange only. Using the later style bearings in an early block is not possible since they will be too big to fit in the smaller machined recess area. All other bearings except the thrust (# 1, 2, 4 & 5) are the same for all years.