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Flo-Tek 203505 Small Block Ford Aluminum Cylinder Head

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Specs
Material Type:
Aluminum
Sold in Quantity:
Each
Finish:
Natural
Cylinder Head Style:
Assembled
Spark Plug Style:
Angle
Combustion Chamber:
58cc
MFG. Part #:
203505
Intake Runners:
180 cc
Exhaust Runners:
62 cc
Intake Valve Diameter:
1.94
Exhaust Valve Diameter:
1.54
Spring Diameter:
1.47
Notes
Recommended Spark Plug: Motorcraft AGSF-32C or equivalent. Bored for 1/2" head bolts.
Flo-Tek 203505 Small Block Ford Aluminum Cylinder Head
Flo-Tek 203505 Small Block Ford Aluminum Cylinder Head
Flo-Tek 203505 Small Block Ford Aluminum Cylinder Head

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Details

Reviews (14)

Q & A (83)

What's in the Box

Info

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.

  • 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)
  • 115 lbs. spring seat pressure
  • Compatible with most flat tappet 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:  AGSF-32C
  • Valve Spring Type:  Single w/ Damper
  • Valve Spring Application:  Hydraulic & Solid Flat Tappet 
  • Valve Spring Diameter:  1.465" O.D.
  • Valve Spring Seat PRessure:  115 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"

Notes

  • 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 and requires the use of adjustable rocker arms like our part number: 91511772. You will need to check your push rod length to determine the correct length before ordering them.
  • 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.
  • We recommend using part #1011543601 with this head, this is an ARP head bolt kit.
  • These Flo-Tek aluminum heads for the small block Ford are specified to take plug number AGSF-32C

Specs

  • Recommended Spark Plug:  AGSF-32C
  • Valve Spring Type:  Single w/ Damper
  • Valve Spring Application:  Hydraulic & Solid Flat Tappet 
  • Valve Spring Diameter:  1.465" O.D.
  • Valve Spring Seat PRessure:  115 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"

Customer Reviews

Rated 4.6 out of 5 by 14 reviewers.
RATING BREAKDOWN
14 reviews
5 Stars
8
4 Stars
6
3 Stars
0
2 Stars
0
1 Star
0
RECOMMEND THIS PRODUCT:

Roy beckett
Verified Purchaser
Verified Reviewer
Beaver, ok

Great quality

June 14, 2016
Great heads for the money for a street build. Great quality and finish. Had to use different guideplates though.
Pros:
  • Low Cost
  • Great Finish
Cons:
  • Have Emission Exhaust Hol
  • Guide Plates Needed Repla
Yes, I recommend this product.
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Frank
Verified Reviewer
Connecticut

A lot of Power for the price.

June 05, 2016
I put these on my 1968 302 Mustang bored .30 over and They woke the engine right up lots of torque lots of power I don't even have that large of a cam and it's such a noticeable difference it will put a smile on my face every time you take it out .
Yes, I recommend this product.
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Joey
Verified Purchaser
Dawson, Al

Flo-Tek

April 29, 2016
Excellent customer service. Great product with an affordable price.
Yes, I recommend this product.
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chuck
Verified Purchaser
Bonaire, Ga

Flo-Tek SBF Aluminum Heads

March 07, 2016
I liked the overall fit and finish of the heads. what short time I had to run them (17year old decided to cut through station and needless to say it'll be a while before I'm driving it again)they seemed very strong. A little disappointed in the pushrod guide plates, little cheap for the heads and several were off-center. Lucky I had others available.. and I think they should come with thermo plugs or at least inform you that they and thread adapters would be needed.
No, I would not recommend this product.
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Mustang Mke
Verified Purchaser
Seattle

Great product.

March 02, 2016
Great value for the money, worked great on my 1966 mustang.
Yes, I recommend this product.
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Frank
Verified Purchaser
Connecticut

Lots of Bang for the buck

February 02, 2016
Easy to install great Iend results
Yes, I recommend this product.
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Brannmark
Verified Purchaser
Verified Reviewer
Sweden

Nice product

December 30, 2015
Nice finish on most parts. Guide plate is very low budget. Holes in guide plates dont fit too well.
Pros:
  • Nice Finish
  • Lightweight
Cons:
  • Low Budget Guide Plate
Yes, I recommend this product.
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5.0 jay
Verified Purchaser
Verified Reviewer
el paso tx

awsome product

October 13, 2015
Strong hard launches
Yes, I recommend this product.
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Engine Wizard
Verified Purchaser
Alabama

great budget head

October 01, 2015
If you are looking for a great budget had you have found it. I have used 3 sets. Hci 302 made 313whp on the dyno.can ask for more for the price!
Yes, I recommend this product.
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the builder
Verified Reviewer
enterprise al

great budget heads!

September 06, 2015
Great heads, made over 300whp in a 93 coupe stock bottom end, only issue was finding the thermactor plugs but issue resolved by local machine shop!
Yes, I recommend this product.
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Page 1 of 2

Product Q&A

83 questions : 88 answers

1 answers

will this fit a '76 Ford 351M/400 engine w/Edelbrock manifold? Engine comes originally from a 1976 Ford station wagon. Virtually the same engine that was later put in the Ford Trucks.

Scooter53147
Clyde NC
March 15, 2015

will this fit a '76 Ford 351M/400 engine w/Edelbrock manifold? Engine comes originally from a 1976 Ford station wagon. Virtually the same engine that was later put in the Ford Trucks.

Answers

March 16, 2015
EricM
No this cylinder head will not fit your engine. This is for a 302 or 351W only.
1 answers

How much can these heads be safely milled? How much can to take off to safely attain a smaller combustion chamber?

merritt5
March 11, 2015

How much can these heads be safely milled? How much can to take off to safely attain a smaller combustion chamber?

Answers

March 13, 2015
EricM
Sorry Flo-Tek does not specify a maximum amount that can be removed from the deck surface.
1 answers

Head Flow Numbers? What are the actual flow numbers? You show them on your website as listed below Lift Intake Exhaust .400 209 137 .500 223 161 .600 248 191 But the article lists them as below Lift Intake Exhaust .400 192 144 .500 203 148 .600 215 149 Thanks in advance

DubH
Oklahoma City, OK, USA
March 01, 2015

Head Flow Numbers? What are the actual flow numbers? You show them on your website as listed below Lift Intake Exhaust .400 209 137 .500 223 161 .600 248 191 But the article lists them as below Lift Intake Exhaust .400 192 144 .500 203 148 .600 215 149 Thanks in advance

Answers

March 02, 2015
EricM
The difference you see between the manufacture advertised flow numbers and the flow numbers from the magazine article is due to different flow benches being used. The same cylinder head will come up with different flow numbers when checking it on different flow benches. This is due to countless factors which are hard to compensate for.
1 answers

can i buy one at a time, what year intake fits these heads, and what year headers ? thanks

chargerdave
ca
February 07, 2015

can i buy one at a time, what year intake fits these heads, and what year headers ? thanks

Answers

February 09, 2015
EricM
The GT40P intake manifold size is the best fit for these cylinder heads. Other intake manifolds will bolt on but the intake port size is similar to the GT40P heads and performance will not be as good with standard SBF intake manifolds. Standard small block Ford headers will fit these heads.
3 answers

Will these heads work with stock ford 289 pistons or will the bigger 58cc combustion chamber reduce compression too much over the original 54cc heads? Can the right cam compensate for the lower compression?

spomerle
January 23, 2015

Will these heads work with stock ford 289 pistons or will the bigger 58cc combustion chamber reduce compression too much over the original 54cc heads? Can the right cam compensate for the lower compression?

Answers

December 12, 2015
JW
Yes they will work fine they should put your compression ratio around 8.7:1 with the small 58cc chambers and 1.94/1.60 valves. I have the GT40p heads on my 289 and they are 58cc heads and it runs fine.
June 03, 2015
angstfree
You will lose some compression but these heads are light years away from your stock heads the will make a lot more power and save a lot of weight and you could always have the heads milled no one makes a sbf head under 58 cc
January 23, 2015
EricM
These heads are not a great option for a stock 289 for just that reason. You will end up with a very low compression ratio.
1 answers

head question I have a 94-96 302 from a bronco all stock, iron heads, non-gt40. I have an edelbrock intake, carb, and a ford e303 cam. With these flotek heads, intake, and cam what's other parts will I need?

BrockGrimes
January 23, 2015

head question I have a 94-96 302 from a bronco all stock, iron heads, non-gt40. I have an edelbrock intake, carb, and a ford e303 cam. With these flotek heads, intake, and cam what's other parts will I need?

Answers

January 23, 2015
EricM
Yes these heads will work with your 94-96 302 engine as well as the Eldelbrock intake and carburetor. You will also need roller rocker arms such as 57534543 to clear the valve springs and head bolts 1012543708 which have a step to allow the use of these heads on your 302 engine.
1 answers

are these heads drilled and threaded for all of the brackets. P/S, AC etc> ?

hallguy
beaumont tx
January 12, 2015

are these heads drilled and threaded for all of the brackets. P/S, AC etc> ?

Answers

January 12, 2015
EricM
Yes these heads have acessory bolt holes in the ends of the heads.
1 answers

I have a 1974 302 bronco. I want to put the 1999 ford explore 5.0 set up on it. do you make these heads in a 60cc. I want to leave the pistons stock and add the gt40 intake and maybe one step hotter cam. I want it to be reliable. no ping

rutcutter
December 20, 2014

I have a 1974 302 bronco. I want to put the 1999 ford explore 5.0 set up on it. do you make these heads in a 60cc. I want to leave the pistons stock and add the gt40 intake and maybe one step hotter cam. I want it to be reliable. no ping

Answers

December 22, 2014
EricM
These heads are only offered in a 58 cc combustion chamber. The compression difference from 58 cc to 60 cc combustion chambers will be so small it would likely never be noticed.
1 answers

will I be able to use my stock push rods I have a 91 351w

carlscavuzzo
Kearney, MO, USA
December 19, 2014

will I be able to use my stock push rods I have a 91 351w

Answers

December 19, 2014
EricM
No stock pushrods can not be used with these heads. You will need hardened pushrods for use with guide plates. Also you will need roller rocker arms such as 57534543 to clear the valve springs on these heads.
1 answers

Flo-Tek 203505 Small Block Ford Aluminum Cylinder Head Will these heads work with 302 1974 motor but I'm putting on a 1999 explorer gt40 intake?

rutcutter
November 28, 2014

Flo-Tek 203505 Small Block Ford Aluminum Cylinder Head Will these heads work with 302 1974 motor but I'm putting on a 1999 explorer gt40 intake?

Answers

November 28, 2014
EricM
Yes these heads will work fine on your 1974 302 engine. They work best with the GT40 type intakes like you plan to use. The intake port size is similar to the GT40 heads.
Page 1 of 9

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