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Afr220

20K views 15 replies 4 participants last post by  Iowan 
#1 ·
hi all I am new here and wanted to see what people thought of afr 220 sbf heads on a 306 at 7500 rpm would do with srp pistons part number 150069 for 13.4.1 compression a hydraulic cam with mid 250 @ .50 and 647 lift would do with a 5 speed and4.30 gears in 1/8 mile I already have the short block put together and I already have the afr 220 heads brand new I know that every one say's that afr 220 are way to big but I bought them because I can grow with cubes later and don't have to sell heads to bye new ones I just wanted to see what power you might think it would make and I had afr 205 on my last car it was a 331 stroker and had a 236 @ .50 cam with 610 lift and ran 98.7 mph in the 1/8 last year on 93 pump gas so with 700 more rpm and 3 and half points more compression and 14 degrees more duration and a tad bit more lift it should at least do 103 mph in the 1/8 mile I would really like to see what every one opinion would be thanks
 
#5 ·
hi thanks the flow for the heads are 330 @ 700 lift on intake and 255 @ 700 exhaust also the intake is 307 cfm on number one four five and eight runner number two three six and seven flow a little more coming in at 315 cfm and no the intake and heads were not flowed bolted up I know that's the best way to know were you really stand flow wise but its just how every thing went down spend a little here and there till its done is the way I am having to do it the holley 750 is untouched and will only be adjusted with jets at the track also the car is a 95 cobra and will weigh around 3100 with me in it thanks again
 
#8 ·
#10 ·
thanks for the info looks like with these heads and cross section and the 306 ci that I am going to need 8500 rpm for max power from the heads so I guess I will be leaving some on the table that's for sure next year at tax time I will do a shp block 3 inch stroke by 4.155 bore and turn that kind of rpm I have a stock block right now that I am going to use this year thanks for the info again
 
#11 ·
update on the 306 high rpm (7800rpm) high compression (12.0.1) afr 220 heads build ok so I wanted to keep posting updates on the route and end results of this build so people like me can have a inside look at what it takes to build your own racing motor and drag car so after talking with a guy on here (turbo2256b) and some simple math I have decided that to take advantage of the AFR 220 heads I would need close to 8800 rpm so I have got with comp cams that specked out a cam for me that will make power to 7800 rpm and I would shift some were around 8200 rpm with that said I just bought some forged rods that are 5.090 stock length that are full floating with bushed ends and have arp 7/16 rod bolts good for 8200rpm and 1000hp I know that they are over kill but like my big heads I would rather have more then not enough so the rods should be here Monday 4/10/2017 and I will take the new rods pistons and crank to be balanced I also bought thicker heads gaskets to bring down the compression from 13.4.1 to 12.0.1 because it will see some street time if anyone has any question's about this build please leave a massage or if you see any problems with this build also let me know what you would do different thanks again for your reply's (turbo2256b) and what are the pro's and cons of using e85 fuel if you have used it please weigh in on that subject thanks
 
#14 ·
UPDATE LOL LOL so happy just wanted to say that I should be starting this beast up next week cant Waite till I turn that key its been almost a year in the making but its been worth it anyone want to guess what power it will make and I made a few last min changes and bumped the compression back up to 13.0.1 cause with my cam it will have a dynamic compression of 8.43.1 and 187 cranking psi so I can run 93 octane on the street I also might sell both of my holley hp 750 carbs and get a 850 dominator carb and might go with 4.30 gears and 29 inch tall slicks I would like to hear every ones guesses on power at fly wheel
 
#15 ·
That is honestly way to much head for 306 unless you are going to turn 10k and have a stick or giant converter. I personally spun 8k on ported iron heads with a 5400 Munsinger converter. ( I'm getting old) that weren't near that big. Car was on the cover of car craft in 2001.
Remember that port volume might make Dyno (computer) hp but will likely be a dog on the track. Port velocity will make a bigger difference since you are low end limited. honestly in a 302, I recommend to run no more then AFR 205 and have a cam in the 255 plus duration @.050 range. Lift is all about what fits and flows. With a roller cam and good range under the curve stay around 575-600 lift. Split duration also works well to help with exhaust scavenging and please dear God make sure you have great headers and NO flow restrictions. ( personally Lost 2 tenths putting race flowmasters on the same package).
 
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