To see these on the dyno, click here: https://www.youtube.com/watch?v=RmWHzcgpImY
I decided to make this video of the Speedway Motors Flo-Tek aluminum small block Ford cylinder heads because I really couldn’t find any information on them besides what was provided by Speedway Motors on their website. So here it is, an in depth look at Flo-Tek PN- 203505 Cylinder heads.
Valve Spring Specifications: (As measured by my machine shop)
1.875″ Installed height
0.650″ Lift retainer to seal
0.780″ Lift to coil bind
100 lbs. @ seat
260 lbs. @ 0.512″ lift (F303 camshaft max lift with 1.6 ratio rocker arms)
General Specifications:
•180cc intake runners
•62cc exhaust runners
•1.94″ intake and 1.54″ stainless steel exhaust valves
•58cc chambers
•3/8″ rocker studs and guide plates
•Hardened valve seats
Note: These heads DO NOT require GT40P specific headers. Any conventional 289/302 header should work with these heads.
I bolted these heads to a 1985 block 306 Windsor without any issues using ARP head bolts torqued to 70 ft./lbs.. The engine has no coolant leak/ combustion chamber leak issues. Valve train geometry was perfect with factory length Ford 5.0L “roller” pushrods and 1.6 ratio comp full roller aluminum rocker arms. The rocker arm studs provided with the kit have the correct thread pitch and diameter to fit comp cams poly-locks.
Note: When bolting these heads to a Ford 289/302 small block, you must use cylinder head bolt bushings to reduce the bolt hole diameter from 1/2″ to 7/16″. I used Trick Flow PN: TFS-51400419 and they worked flawlessly.
Please comment about anything and thanks for watching!