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Flowtech Upright Headers - 11551FLT

Flowtech Upright Headers - 11551FLT

SKU: 11551FLT
Regular price $434.95 USD
Regular price Sale price $434.95 USD
Sale Sold out


Flowtech Headers are the perfect combination of quality and value. These Big Block Chevy Upright headers available in 2-1/4" tube diameters are ideal for even big cubic inch Big Block Chevy engines


  • CNC Mandrel-bent tubes provide consistent tubing diameters for smooth flow and increases the cylinder scavenging effect and improves engine breathing
  • Heavy duty 16-gauge 409SS tubing for increased strength and durability
  • 2-1/4” tubing diameter for increased exhaust flow increasing performance and improved throttle response
  • Extended 4” collector for maximum strength and exhaust flow
  • Extra thick 7/16” header flange for a leak-free seal and maximum strength
  • Welded-in collector merge spears to control exhaust gas re-entry into primary tubes
  • Center of exhaust port to end of collector length is 33-1/2"

  • 1975-1995 Chevrolet G30
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  • 1968-1974 Chevrolet K10 Suburban
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  • 1968-1974 GMC K15/K1500 Suburban
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  • 1968-1974 GMC K25/K2500 Suburban
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  • 1992-1995 Chevrolet C2500 Suburban
  • 1992-1995 Chevrolet K2500 Suburban
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  • 1975-1978 GMC C15 Suburban
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  • 1987-1988 Chevrolet R20
  • 1987-1988 Chevrolet R20 Suburban
  • 1987-1988 Chevrolet R30
  • 1987-1988 Chevrolet V20 Suburban
  • 1987-1988 Chevrolet V30
  • 1975-1976 GMC G25
  • 1976-1977 GMC K25 Suburban
  • 1973-1974 Chevrolet G10 Van
  • 1973-1974 Chevrolet G20 Van
  • 1973-1974 Chevrolet G30 Van
  • 1979-1980 GMC C1500
  • 1979-1980 GMC C1500 Suburban
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  • 1969-1970 Chevrolet Nova
  • 1973-1974 Chevrolet Blazer
  • 1969-1970 Chevrolet Estate
  • 1989 Chevrolet R2500
  • 1990 Chevrolet V2500 Suburban
  • 1976 GMC G35
  • 1976 GMC K15
  • 1980 GMC K1500
  • 1976 Chevrolet G20
  • 1968 Chevrolet Chevy II

Application Big Block Chevy
Brand Flowtech
Collector Diameter 4.00 inch
Emission Code 4
Engine Big Block Chevy
Finish Natural
Header Finish Natural
Header Style Upright
Primary Tube Dia. 2-1/4 inch
Product Type Headers
Tube Material 409 Stainless Steel
Warning California Proposition 65
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Policies and FAQs

Return Policy

We accept returns on products within 30 days of delivery. Return shipping is the responsibility of the buyer unless we, the seller, are at fault.

Fault reasons include but are not limited to:
  • Buyer was shipped the wrong product
  • Buyer was shipped a damaged product
  • The product page had incorrect fitment and the part does not fit the Buyer's vehicle
The Buyer will not be refunded outbound shipping unless the Seller (Modern Day Muffler & Brake) is at fault.
In cases where the Buyer purchases and ships the return please note that if the Shipper (ex. USPS, FedEx, UPS, etc.) loses the return we will not be able to offer a refund as the Buyer must contact the Shipper and make a claim.
All products must be returned in original condition, meaning that the product must not be damaged, installed, or missing pieces/parts. If the product is not in original condition a deduction will be issued of up to 100% of the purchase price of the product.
Opened boxes, plastic bags, and other packaging are not considered damage (excluding single use items such as, but not limited to, liquids, software, and other components that cannot be reused/resealed).
When we, the seller, are at fault, please Contact Us for a return label, products returned with a shipping label not provided by the seller will not be refunded to the buyer. Please also note that our return labels are issued with the dimensions and weight of the original shipment, if the product is being returned in any box/package besides the original please Contact Us with the dimensions and weight.

Returns must be sent to this address:
Modern Day Muffler & Brake
774 Broad Street
Wadsworth, OH 44281
Products returned directly to a manufacturer or the incorrect address may be issued a deduction or denied a refund entirely.
If a product was delivered outside the 30 day return window or is no longer in original condition please contact us as we may be able to issue a refund in store credit and/or with a deduction. If this is the case please Contact Us as these situations are handled on a case by case basis.
If there are any questions, concerns, or doubts about return eligibility please Contact Us and we would be more than happy to assist you.

This page and policy were last updated: July 14th 2023


This is the line that runs from the front of the vehicle to the rear. On most vehicles it connects to a junction then you will have rear axle lines. On a few cars the intermediate lines will connect to the rear wheels. It is recommended to change the axle lines if you are replacing the intermediate lines.

Our kits include all of the solid metal lines for that section of the vehicle.

We are happy to help! Please help us to help you by going to our return form and filling out the form as best as you can in order to request a return.

  • Modern Day stands by our parts and is happy to accept returns within 30 days of purchase. Parts must be in new condition.
  • If a part arrives damaged, or is defective, Please report it to us immediately. So we can handle it for your promptly.

Yes but you will need to order in advance. All of our items are not stocked at our location. So please place your order online and we will notify you when it is ready for pick up.

Unfortunately we cannot offer single lines outside of kits

Yes, all are covered by the manufacturer's standard warranty. Most warranties cover the cost of parts. Any installation or other fees are non-refundable.

Online we accept PayPal and all major Credit Cards. If your are picking an item up we gladly accept cash.

We can only ship to your confirmed address in PayPal or your billing address if you pay with a credit card.

Orders typically Arrive within 3 to 10 days depending if it is a stocked item or something we have manufactured at time of sale.

Yes please send us a message through our custom orders page.

Yes, but items sent out of the continental U.S. may incur additional charges based on their destination

The left and right sides on a vehicle are determined as though you were sitting in the driver's seat. The left is the driver's side, and the right is the passenger's side.

Check it again tomorrow. It takes up to 1 day for the carrier to give status and a delivery date. UPS and FedEx provide delivery dates, USPS usually does not but they take no longer than 5 business days.

Yes! Thank you for your military service!

Still have a question or concern?  Please contact use our contact us form!

Yes! Thank you for your military service!

Warranty Information

Customer service is our top priority and because we value your time and energy we ask you to visit our Contact Us page and reach out so that we may assist you in finding the correct warranty for your product. Please include your name, the name on the order, the order number, and the SKU of the product to ensure the quickest and most accurate response to your inquiry.

Product Notices

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