Product Summary

  • Includes support strap, spacers and new bolts for the center main cap
  • Also can be used on the front main cap but pan modification is required
  • Requires no machine work
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Key Specs

MFG. Part #5603408
BrandSpeedway Motors
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Need To Know

Quick and Easy Returns

Return Policy

Speedway Motors 5603408 Details

If you're building a serious flathead for either street or racing, you need one of these flathead main cap supports. These supports include the support strap, spacers and new bolts for the center main cap. It adds an incredible amount of strength to the lower end. Can also be used on the front main cap but pan modification is required. Requires no machine work.

CARB Warning

For race/ off road use or for use on pre-1966 vehicles.

Emissions warning: this part only legal for sale or use in California for racing (competition) vehicles which may never be used, registered, or licensed for use upon a public highway, or if installed in vehicles model-year 1965 or older; motorcycles model-year 1977 or older; or off-highway recreational vehicles (such as off-road motorcycles and all-terrain vehicles) model-year 1996 and older. Any other use renders the vehicle tampered and not legal for use on California public highways (any public street or roadway, public dirt road, public park, or publicly maintained right of way open to the use of the public for vehicular travel). Violations subject to $37,500 penalty per violation per vehicle, revocation of registration, loss of use on California public right of ways, and proof of correction for tampering. There are similar restrictions and penalties under federal law and the laws of all other states with penalties under federal law of up to approximately $45,268 per tampered vehicle and/or engine.

Speedway Motors 5603408 Specifications

KEY SPECS
MFG. Part #5603408
BrandSpeedway Motors

Ratings & Reviews

4.9

7 Reviews

Overall Assessment

Our product is highly recommended for its easy installation, practicality, and high-quality build, important factors that set it apart from other similar products. Described as a 'fantastic' and 'great addition' to build projects, users particularly praise its ability to effectively strengthen the centre main of all flatheads. It fits easily, as confirmed by the machine shop, and it's well-built, which guarantees safety and durability. However, some users suggest improving the instructions to instill more confidence during installation.

4.9

7 reviews

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Filter by Ratings

I would buy again

5.0

2 years ago

Po' Man

NC

Verified

Good Quality

Would Recommend

It's been installed while the flattie was on an engine stand

5.0

3 years ago

KenRMer

Seven Hills, Ohio

Verified

Engine still on the stand as more work needs to be done

Would Recommend

Nice part

5.0

4 years ago

Flathead

Akron oh

Verified

Great addition to build

Would Recommend

Yes, I would buy and continue to buy this product

5.0

6 years ago

Spike

Melbourne Australia

Verified

I use this product to strengthen the centre main on all my flatheads I build. Good quality and the machine shop rates them as an easy fitment.

Would Recommend

I would buy this product again

5.0

8 years ago

Spike

Melbourne Australia

Verified

Fantastic product and easy to install

Would Recommend

Missing something

4.0

9 years ago

Not sure

Bel air, md

Verified

Seems good however the directions are very lacking. Not confidence inspiring.

Would Recommend

great made product [...]

5.0

16 years ago

Fuzzy

Portland Or.

used in 52 ford flathead. Very well built

Would Recommend

Showing 7 of 7 reviews

Questions & Answers

3 Questions • 3 Answers

The original center cap bolts had lock washers under the bolt heads. Should those lock washers be used with the bolts for the cap support?

by Ktgovols

• 10 years ago

1 answer

Can this Main Cap support work on the rear(flywheel) Main cap too ? I've purchased 1 of these for the center main cap, and I'm wondering if it will fit on the rear main cap too? The block is away at the machine shop so I can't just run out and look. if it does, I want to get it ordered...

by Aird

• 12 years ago

1 answer

is there a certain torque spec for the center bolt, or just run it up snug?

by aaronc

• 13 years ago

1 answer

3 of 3 questions shown

Fitment

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Customer Impersonation Script