Flo-Tek 203505 Small Block Ford Aluminum Cylinder Head

#7223000

Flo-Tek 203505 Small Block Ford Aluminum Cylinder Head

Name: Flo-Tek 203505 Small Block Ford Aluminum Cylinder Head
Brand: Flo-Tek
SKU: 7223000
Price: 469 USD
Availability: InStock
Rating: 4.5 (44 reviews)

44 Reviews

48 Questions

Features hardened locks and retainers
Head is compatible with most roller camshafts
Includes high-temp exhaust seats and bronze guides

$469.00

/each

In Stock

Quantity

Need Help? Call to Order

Add to a list

Select an engine to verify Fitment

Select Engine

Product Summary

Assembled Cylinder Head Style, Aluminum, Natural

Features hardened locks and retainers
Head is compatible with most roller camshafts
Includes high-temp exhaust seats and bronze guides
Made from lightweight, yet strong aluminum with a natural finish
Intake valve diameter measures 1.940" and the exhaust valve diameter measures 1.540"

See more details

Key Specs

Cylinder Head Style	Assembled
Material Type	Aluminum
Finish	Natural
Combustion Chamber Volume	58cc
Intake Runner Volume	180cc

See more specs

Need To Know

Need help?

855.313.9176

View the Help Center

Quick and Easy Returns

Return Policy

Installation Details

Installation Tips

These Flo-tek aluminum heads are the answer to the performance enthusiast and work on the small block Fords including the later EFI series when used in conjunction with an aftermarket intake, carb, and camshaft. Aluminum heads allow for a higher compression ratio than cast heads without creating pre-ignition problems. Check your piston usage with the 58cc combustion chamber for accurate ratio computation.
If using the heads on a 289 or 302 the upper row is 80 pounds net and the lower is 70 pounds. Torqued in stock sequence and increments. If using on the 351 with the larger bolts it is 100 pounds net torque in same sequence and increments as stock.
The head uses 3/8 rocker studs 915-99156 and requires the use of adjustable rocker arms like our part number: 915-11772. You will need to check your push rod length to determine the correct length before ordering pushrods.
Depending on the how much extra lift you are going to go with, you may also need different valve spring retainers that allow for more valve spring installed height
289 and 302 engines with 7/16” head bolts use 1012543708. 351W engine with ½” head bolts use 590HBK35100.
These Flo-Tek aluminum heads for the small block Ford are specified to take plug number NGKR5671 or Autolite AR3932
Valve springs are suitable for most hydraulic flat tappet and mild street hydraulic roller camshafts

Have a Question?

Call one of our U.S.-based customer service professionals.

Tech Support - Opens at NaNpm (UTC)

Flo-Tek 203505 Details

You don't need to spend a fortune to get a top-performing, lightweight aluminum cylinder head for your small-block Ford V8. This Flo-Tek head has a long list of high-end features, minus the hefty price tag.

Will likely need to plug the EGR connection holes in the end of these heads on 86-up fords. Please use 5775804 to do so. One set of plugs will do a pair of heads.

Head is sold individually
180cc intake runners
62cc exhaust runners
1.94" intake and 1.54" swirl-polished exhaust valves
58cc chambers
Performance valve springs (.550 lift)
130 lbs. spring seat pressure
Compatible with most roller camshafts
Hardened locks and retainers
PC seals
High-temp exhaust seats
Multi angle valve job
Bronze guides
3/8" rocker studs and guide plates

See how this Flo-Tek head stacks up against the competition in Car Craft Magazine's tech article; 6 Small Block Ford Cylinder Heads That Work.

Head Flow Specs:

Lift Intake Exhaust
.400 209 137
.500 223 161
.600 248 191

Application

Recommended Spark Plug: NGKR5671 or Autolite AR3932
Valve Spring Type: Single w/ Damper
Valve Spring Application: Roller
Valve Spring Diameter: 1.465" O.D.
Valve Spring Seat Pressure: 130 lbs.
Valve Spring Rate: 240 lbs/in.
Max lift: 0.550"
Intake Valve: 1.94"
Exhaust Valve: 1.54"
Valve Type: Stainless, Swirl-Polished
Air Flow Data:
- Intake
  - 223 CFM @ .500"
  - 248 CFM @ .600"
- Exhaust
  - 161 CFM @ .500"
  - 191 CFM @ .600"

Specs

Recommended Spark Plug: NGKR5671 or Autolite AR3932
Valve Spring Type: Single w/ Damper
Valve Spring Application: Hydraulic & Solid Flat Tappet
Valve Spring Diameter: 1.465" O.D.
Valve Spring Seat Pressure: 130 lbs.
Valve Spring Rate: 280 lbs/in.
Intake Valve: 1.94"
Exhaust Valve: 1.54"
Valve Type: Stainless, Swirl-Polished
Air Flow Data:
- Intake
  - 223 CFM @ .500"
  - 248 CFM @ .600"
- Exhaust
  - 161 CFM @ .500"
  - 191 CFM @ .600"

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.

WARNING:

Cancer and Reproductive Harm – www.P65Warnings.ca.gov

CARB warning

Flo-Tek 203505 Specifications

KEY SPECS
MFG. Part #	203505
Brand	Flo-Tek
Cylinder Head Style	Assembled
Material Type	Aluminum
Finish	Natural
Combustion Chamber Volume	58cc
Intake Runner Volume	180cc

GENERAL
Exhaust Runner Volume	62cc
Combustion Chamber Volume Range	50cc - 59cc
Intake Runner Volume Range	180cc - 189cc
Exhaust Runner Volume Range	60cc - 69cc
Spark Plug Style	Angle
Intake Valve Diameter	1.94"
Exhaust Valve Diameter	1.54"
Spring Diameter	1.47"
Notes	Recommended Spark Plug: NGKR5671 or Autolite AR3932 . Bored for 1/2" head bolts.
Sold in Quantity	Each
GTIN Code	850134007075

Ratings & Reviews

4.5

44 Reviews

Overall Assessment

Customers appreciate the high quality and affordability of the product, often stating that it offers excellent value for money. Many commend its performance, highlighting the increase in power and torque it provides. Users also mention its good fitment and finish, praising its simple installation process. However, some customers noted issues with the product's guide plates, which were perceived as low-quality and poorly fitting. Still, these heads have been consistently recommended as an excellent choice for a budget street build. Despite minor imperfections, users recognize that the product offers performance comparable to more expensive heads, making it a "best bang for your buck" purchase.

Write A Review

4.5

44 reviews

Most Liked Positive Review

5.0

Excellent heads

Very nice heads. When I received them I took them to my head builder and he couldn't believe I only paid 800+ for them. Now at [$] is a complete steal!I then installed w/stage 1 cam.They have been on my drag car for 3+ yrs without a hic-cup.Unbelieveable is my only word for these!

Most Liked Negative Review

1.0

Mine needed a lot of work.

I had to fill and move the rocker stud holes about .160" to get reasonable pattern on the valve tips, The required clean up around the seats in the chambers to unshroud the exhaust valves was a pain. My guide plates didn't match the valve-stem spread meant that I had to fill and remachine the slots. Other than that I just cleared the very bottom of the rocker bolt holes for better oil drainback. The work pretty good on my combo (that hasn't and won't see a dyno). All in all, I'd do something different the next time. I got mine from Tri-state heads.

Filter by Ratings

Sort Reviews

I would buy this product again

5.0

a year ago

Utah

Verified

The items I purchased are engine parts, and I have not yet built the engine. But the cylinder heads appear to be of high quality and were delivered in a timely manner and come recommended by other commenters. It will probably be about a year before I can report on their performance.

Would Recommend

Flowtech cylinder heads

5.0

a year ago

Ryno

Idaho

Verified

Can't be these heads for the price throwing them on a 351w with 256 cam in a marine app.

Would Recommend

I would buy this product again.

5.0

a year ago

Ordin

Arizona

Verified

The quality is very good. This is the second set of these heads I have purchased. I am pleased with the performance and reliability.

Would Recommend

Incredible shipping and great service my new go to parts hou

5.0

2 years ago

Mikey

Lakewood Colorado

Verified

Perfect fitting and looks great

Would Recommend

Great buy for the price for great no fitment issues

5.0

3 years ago

Mr brown

Muskogee, ok

Verified

I used these on a 302ci that will be going in a 86 ltd crown Vick

Would Recommend

302 Mustang hears

5.0

3 years ago

Scsarge81

Crossville, TN

Verified

I was looking for these and Speedway had them in stock and for the right price. Fast shipping only confirmed I picked the right speed shop for my purchase. Thanks

Would Recommend

Absolutely

5.0

3 years ago

Jim

Graham wa

Verified

Price is great, fit is great, performance is great.

Would Recommend

Very Nice

5.0

3 years ago

Streetrodder23

Elizabethville Pennsylvania

Verified

The product was very nice, good quality and will do the job.

Would Recommend

I will not be buying them assembled again.

3.0

4 years ago

Verified

They advertise this as a flat tappet cam head however spring pressure is too high for even stock camshafts.

Would Not Recommend

Good head for the price

5.0

4 years ago

West Michigan

Verified

Putting these on a 302 sbf that's going into a pinto wagon. The heads seem like a good quality especially for the price.

Would Recommend

Load More Reviews

Showing 10 of 44 reviews

Questions & Answers

48 Questions • 11 Answers

Sort Questions

Will these heads work with my 35-320-8 xtreme energy comp cam?

by Jr

• 4 months ago

1 answer

View Answer

What is the torque specs for the rocker studs?

by Mickey L Worley Sr

• a year ago

1 answer

View Answer

I purchased a set of these heads for my 289 with a mild hyd flat tappet cam with rocker arm do you recommend

by Michael

• 2 years ago

1 answer

View Answer

What do the exhaust ports measure? Thanks

by F100

• 3 years ago

1 answer

View Answer

Is there any fitting issues with the headers especially the exhaust side? I read a lot of people complain about budget heads and header problems

by Dave

• 6 years ago

1 answer

View Answer

Can I use COMP Cams Magnum Steel Roller Tip Rocker Arms 1431-16 with these heads?

by BRUCE

• 6 years ago

1 answer

View Answer

I have these heads on a '74 302. Can I reuse these heads on a '95 351?

by norrillous

• 7 years ago

1 answer

View Answer

Will these heads fit my 260 ford small block. Currently have cast iron heads performer manifold mild cam. What rockers and stud set would I need.

by Randy

• 7 years ago

1 answer

View Answer

are these heads compatible with a ford roller cam with a .495 lift and roller rockers

by Mike

• 7 years ago

1 answer

View Answer

Would these be ok on 351/427 stroker with reverse dish pistons -16cc 9.5 block?

by Tracis

• 7 years ago

2 answers

View Answers

Load More Questions

10 of 48 questions shown

Fitment

1964 AC Shelby Cobra

Ford 289

1968-1973 AC Shelby Cobra

Ford 289

1967 DeTomaso Mangusta

Ford 289

1963 Ford 300

Ford 289

1966-1968 Ford Bronco

Ford 289

1963-1967 Ford Club Wagon

Ford 289

1963-1968 Ford Country Sedan

Ford 289

1963-1968 Ford Country Squire

Ford 289

1964-1968 Ford Custom

Ford 289

1964-1968 Ford Custom 500

Ford 289

1963-1968 Ford Fairlane

Ford 289

1964-1968 Ford Falcon

Ford 289

1964-1965 Ford Falcon Sedan Delivery

Ford 289

1963 Ford Ford 300

Ford 289

1963-1967 Ford Galaxie

Ford 289

1963-1967 Ford Galaxie 500

Ford 289

1964-1969 Ford GT40

Ford 289

1965-1968 Ford LTD

Ford 289

1964-1968 Ford Mustang

Ford 289

1963-1968 Ford Ranch Wagon

Ford 289

1960-1961 Ford Ranchero

Ford 289

1965-1968 Ford Ranchero

Ford 289

1964 Ford Sprint

Ford 289

1968 Ford Torino

Ford 289

1964-1967 Mercury Caliente

Ford 289

1966-1967 Mercury Capri

Ford 289

1964-1968 Mercury Comet

Ford 289

1967 Mercury Commuter

Ford 289

1967-1968 Mercury Cougar

Ford 289

1963 Mercury Country Cruiser

Ford 289

1964-1968 Mercury Cyclone

Ford 289

1963 Mercury Meteor

Ford 289

1968 Mercury Montego

Ford 289

1964-1967 Mercury Villager

Ford 289

1966-1967 Mercury Voyager

Ford 289

1963-1968 Shelby Cobra

Ford 289