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Main Caps We carry both used original type main caps, and aftermarket billet types. "RB" (413/426/440) engines use different caps then "B" (361/383/400) engines, since the main bearing size is different. Used stock replacement caps are available individually or in sets. Don't throw away that block just because the caps were lost years ago. |
| Our new billet steel main caps
finally allow you to upgrade the strength of your block for an incredibly
reasonable cost! With the increased popularity of our stoker kits and forged
rotating components, the block and factory cast iron main caps are often
finding themselves as the weakest link in modern stroker engines making over
600-650 horsepower. With these upgraded caps, you can extend the reliability
of your factory block far beyond that range... and for a small fraction of
the cost of other main caps on the market, or especially an aftermarket
block. These caps are FACTORY HEIGHT. That means they are compatible with
any off-the-shelf Big Block Mopar main studs or bolts (no special lengths
required) and they'll work with any of the aftermarket girdles available
(for a super strong combination) AND you won't have interference issues with
the aluminum rear seal cap due to these caps being taller than stock. The
bolt holes are spot faced to make sure the main stud nuts and washers have
a flat, even surface to clamp down onto, and the thrust surface is already
pre-cut into the #3 cap. We've thought of everything. And, the best part? We
include ALL FIVE caps for the incredible price listed below.
A great choice for upgrading an old set of cast iron factory caps, or even for replacing a set of missing originals. These work with both "B" and "RB" engines. As with any aftermarket main caps, fitting the caps to your block's registers and line boring and/or honing is required. Part No: 200-1039 - Set of 5 Billet Steel Main Caps - Price: $139.95 /set of 5 |
| We have a limited supply of Mopar
Performance high strength Ductile Iron main caps, part number P5249132.
Brand new set includes all 5 caps. The high strength ductile iron is
considerably stronger than the 40 year old factory cast iron caps from used
blocks. Racer net on these back in 1996 was $280! We have them on clearance
for less than a third of that, while supplies last. These are great for
upgrading an old set of factory caps, or even for replacing a set of missing
originals. As with any aftermarket main caps, line boring is required. Once
these are sold out, they're gone forever!
Part No: P5249132 - Mopar Performance Ductile Iron Main Caps - 2 bolt - "B" and "RB" Qty: 5 - New - Price: $89.95 |
| Used "RB" main caps. As pictured
above. Call for availability. Part No: 100-1102 - Set of 5 "RB" Stock replacement Main Caps- Used. Price: $89.95 Part No: 100-1102A - Single "RB" Stock replacement Main Cap (specify bearing #) - Used. Price: $34.95 A note on thrust bearings (#3 caps:) 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. This means there are two different #3 caps for both "B" and "RB" engines, one for 1973 and earlier, and one for 1974 and later. 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, so remember to specify block year when ordering #3 main caps.
We refer to the pre '74 thrust caps as "Early" and the 1974 and later as "Late." It is possible to use the early (smaller) #3 caps in the later blocks, however you will need to use the early bearings and not get the added benefit of the increased thrust surface area. Using the later caps in an early block is also possible, however you will still need to use the early style bearings, since the later style would be too big to fit in the smaller machined recess area. It is possible to have your machine shop enlarge the machined recess in the block and/or cap with a flycutter during line boring to enable use of the later style bearings. Also, all other bearings except the thrust (# 1, 2, 4 & 5) are the same for all years. |
| Used "B" main caps. As pictured
above. Call for availability. Part No: 100-1103 - Set of 5 "B" Stock replacement Main Caps- Used. Price: $99.95 Part No: 100-1103A - Single "B" Stock replacement Main Cap (specify bearing # & year) - Used. Price: $34.95 See above notes when ordering #3 thrust bearing "B" main caps. |
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