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Skip White Performance
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Kingsport, TN 37660

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 423-722-5152

SBC CHEVY 421 SHORT BLOCK KIT FORGED CRANK RODS PISTONS 4.155x3.875 -9.5cc DISH

$3,350.00

Available



Product Information

UPC371243306553
Product TypeShipped Product
Shipping Cost $250
Number of reviews 0

SBC 421 cid COMPLETE SHORT BLOCK KIT. FULLY FORGED, DART SHP BLOCK 4.155 bore, SCAT 4340 CRANK 3.875 stroke, -9.5cc RD dish pistons

READY TO ASSEMBLE

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The Probe SRS pistons have a -8cc reverse dome dish. Compression ratio will be approx. 11.50:1 when used with 64cc heads, or 10.67:1 with 72cc heads. Perfect for street rod use on pump when used with a 72cc or 75cc head.


Item Code

15211-030

Vendor Name

Probe Industries

Product Type

Pistons

Product Model

Sportsman Race Series - SRS

Engine Displacement (cu.in.)

421

Engine Family

CHEVROLET - Small Block V8

Material

2618- Forged Aluminum

Base Bore (in)

4.125 + .030 = 4.155

Stroke (in)

3.875

Rod Length (in)

6.000

Compression Height (in)

1.080

Top Type

Reverse Dome

Net Head Volume (cc)

-9.5cc

Deck Thickness (in)

0.205

Valve Pocket Cutters

2.250 I - 2.250 E

Valve Pocket Depth (in)

.250 I - .250 E

Wrist Pin Diameter (in)

0.927

Wrist Pin Length (in)

2.500

Wrist Pin Weight (g)

118

Pin Lock Type

Dbl Spiral

Ring Set #

315-0036

Top Ring Groove Size

1/16 in.

Second Ring Groove Size

1/16 in.

Oil Ring Groove Size

3/16 in.

Top Ring Land (in)

0.220

Second Ring Land (in)

0.155

Bottom Ring Land (in)

0.075

Our choice of rods are the 6 inch SCAT COMPETITION SERIES rods with ARP cap screws.

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The Scat Pro-Comp extreme duty I-beam rods should not be mistaken for ProComp rods. These rods are made exclusively by Scat, and have nothing to do with the ProComp company. The critical sizing and installation of the ARP cap screws is performed on a Sunnen machine in the USA by Scat Industries. These rods are excellent for those wanting the extra security offered by a rod with 7/16 ARP cap screws.

Take notice of the design of these rods. They are far superior to conventional style I-beam rods. We are now using this rod in all of our Stage 4 and up SBC engines. We also use this rod in our big block 540/555 engines, making approx. 700+hp

If you do a search on the Scat Pro-Comp rods, you will find a vast amount of info on many car forums. All of the info is 100% positive. These rods are run in engines that not only produce high horsepower levels, but also run at continuous RPM. Notice the general appearance in the pictures. These rods do look impressive. The style is reminiscent of a steel billet rod.

The fact that these rods are incredibly strong and well made, coupled with the fact they are light weight and offer better clearance than any H-Beam rod on the market, made it an easy decision to use them in all of our high horsepower street/strip engines.

The Scat Pro-Comp extreme duty I-beam rods with ARP 8740 Series cap screws. are not to be mistaken by the model name, "Pro-Comp" These rods are made exclusively by Scat, and have nothing to do with the company known as Procomp. They are not only a much better designed rod, they are made from forged 4340 alloy. The critical sizing of both ends of the rods is performed on a Sunnen machine in the USA by Scat Industries. These rods are excellent for those wanting the extra security needed in high horse power applications. Take notice of the design of these rods. They are far superior to conventional style I-beam rods. We are now using these in all of our Stage 4 and 5 sbc engines. These engines are making up to 630hp. We also use the 6.385 version of these rods in our big block 540 engines, making approx. 700+hp We find this rod to be slightly heavier than the regular I-beam rods on the market, yet slightly lighter than most H-Beam rods. This weight range is usually right in the workable area for crank balancing. If you do a goggle search on the Scat Pro-Comp rods, you will find a vast amount of info on many car forums. All of the info is 100% positive. These rods are ran in engines that not only produce high horse power levels but also running at continuous RPM. Notice the general appearance in the pictures. These rods do look impressive. The style is reminiscent of a steel billet rod. They are clearanced well for most stroker applications, but as a rule, do check for clearance before finalizing your build. The fact that these rods are incredibly strong, and well made coupled with the fact they are light weight and offer better clearance than any H-Beam rod on the market made it an easy decision to use these in all of our high horse power street/strip engines. This is the perfect upgrade to your rotating assembly.

  • The ultimate I-beam rod that incorporates the strength and technology of the H-beam rod.
  • One rib cap design for added strength and bearing support
  • Polished beams to eliminate stress risers
  • Profiled clearance for stroker applications
  • Special hollow dowels and huge 7/16'' cap screw bolts greatly increase strength and horsepower capabilities
  • .927 WRIST PIN WEIGHT

    2.100 PIN DIAMETER

    .940 BIG END WIDTH

    WEIGHT 590 average.

    We have noticed some engine builders using low cost generic rods and crankshafts in their engines. These non-branded, (no-name) products are often poor quality in many ways. You will notice many of the low end engine builders fail to mention the actual brand of the rods or cranks used in their engines. Upon further investigation you will find such parts not to be a branded name product. They may label these parts with a name, but one that is totally unrecognizable in the industry. Our experience in years past with such rods and cranks has been disappointing to say the least. Besides the obvious issues such as incorrect sizing and machining that is difficult to correct, the questionable alloy these items may be produced from and the potentially incorrect heat treating methods used, could prove to be disastrous. Little can be done to verify this and nothing can be done to correct it. Failures of such critical parts will usually result in catastrophic damage to the engine. As you may have noticed, this is why we specify the brand name and series of every part used in our engines.

    Many of the inferior "no-name" rods on the market will also have "no-name" rod bolts in them. We have seen these bolts before, and they are very low quality. They don't have ARP's rolled thread design, and they don't torque down with the same characteristics as a genuine ARP bolt. It's not just a matter of having a different brand bolt in the rods; these bolts are low quality in many ways. They have been known to fail in engines to a much greater degree than a high quality rod bolt, and this failure usually causes catastrophic damage in the engine. Beware of rods that don't mention the rod bolt brand. As far as we're concerned, ARP bolts are the only brand we would ever use or accept in a set of rods.

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    This is a file photo. Actual appearance may vary.

    Dart SHP 2 pc rear main seal block with splayed center main caps. Scat 4340 fully forged crank 3.875 stroke, Scat HD competition rods with 7/16 ARP-8740 cap screws, Probe 2618 aircraft race grade pistons 4.155 bore size. Hastings plasma moly, ductile rings. 1/16 1/16 3/16 size.

    Pictured below is the Dart High Performance Block that is included. Notice the massive splayed caps. This block is built for extreme duty.

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    The block is bored to size with our new Centroid DRX-750 touch probe block boring machine. We then deck the block with our Centroid block machine to an ra finish of approx. 15. Pistons will sit at zero deck allowing for a perfect quench/squish zone.

    We often find many brand new blocks to have a sloping deck of up to 4 thous. When were finished decking the block it is within one ten thous. accuracy from end to end. Many machine shops fail to catch this as the machinery they use doe's not allow for such accuracy. The final step is to wash the block in our high pressure parts washer. You should always re-wash your block and all of the parts before assembly. This is to assure that you know the block is free of contaminants.

    SCAT 4340 FORGED CRANK. 3.875 STROKE.

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    A complete set of King HP rod and main bearings are included with the crankshaft. The HP bearings by King are far superior to the regular King bearings.

    The part number for this crankshaft is 4-350-3.875-6000 This is a first line product directly from Scat engine products.

    The Scat Crankshaft is one of the best values you will ever find when it comes to crankshafts. These cranks are far superior to any of the other low cost cranks on the market. We feel the same way about the King bearings. The bearings are included with the crankshaft.

    SCAT 4340 FORGED STEEL CRANKSHAFT RATED AT 800+ HP

    PRO RACE BRAND DAMPER.

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    Pro Street Series, made by Pro Race Performance Products. Non S.F.I. internally balanced, (non-weighted)

    6.75 INCH DIAMETER.

    SFI APROVABLE FLEXPLATE INCLUDED.

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    SFI APROVABLE HD FLEXPLATE. This flexplate will resist cracking and warpage, leading to imbalance in the engine. One good telltale in identifying a cheap flexplate is the lack of welding on each side where the plate mates to the ring gear. They usually have a pale grey color to them, as they are not coated, and will rust quickly. Ours are welded on both sides, and are approximately 30 thousandths thicker than an OEM plate.

    The actual flexplate appearance may vary, with either the zinc dichromate finish or the black powder coat finish.

    This is an extremely heavy duty flex plate.


    Your actual flexplate is balanced with the rotating assembly. Those running manual trans will need a flywheel, which we offer at an additional cost.

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    This short block kit is not assembled. See our other listings for this in assembled form.

    We also offer this setup in a 427 cid size.

    We do our own balancing with our brand new, 2013 model CWT 5500 Series Balancer. This machine will replace our 2011 Hines Legend balancer. The CWT 5500 is the absolute ultimate for precision balancing. When we balance the assembly for this engine, it will be to very high specs. Usually plus or minus 1-2 grams. We include a balance sheet with your setup.

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    The damper is included with this setup. The flexplate is SFI aprovable. Bearings are King HP race grade series. The cam bearings are from Dart. They are special coated bearings, and are very high grade. The rods used are Scat I-beam, competition series. These are not your regular Scat I-beam rods, but a much better rod used in many race engines. They have 7/16 ARP 8740 cap screws, polished beams. They are made from 4340 alloy. It is not uncommon to see engines making 700+ horse power using these rods.

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    MELLING FREEZE PLUG KIT INCLUDED.

    Note from our company President, Skip White

    We are often asked if the SHP block is able to handle high horse power builds. My answer is that if your building this for street and strip applications, then this block will handle most any buidup you do. 800hp builds are not uncommon with this block. Durability and longevity with high horsepower builds are not a problem with the SHP Dart block. Nos, twin turbo, blower, high compression builds are also not a problem. As many of you know, Dart has a one step up from this block known as the Little M series. Those blocks are slightly stronger in a few areas, and are more suitable for running extreme build ups, or engines running very high horsepower, and continuous duty such as dirt or circle track or all out competition drag racing. Those using the Little M block for drag racing often exceed 800hp, combined with very high rpm, (8,000 up to 11,000) The SHP Dart block should last a lifetime on a street rod, even if built up to 800hp. You will also find this block used in many marine applications.

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