AFR PN 1660

Flowtested on a 3.900 bore
Radiused Inlet / Exh. tested with 1.875 curved pipe

NOTE: "Stock" combustion chamber volume is 65 cc's. They can be safely milled to the mid/high 50's but at the expense of slight loss in flow.

(Also including AFR 205 #'s for comparison (PN 1510)

INTAKE #'s

LIFT.....225cc....205cc

.200......141......140
.300......205......200
.400......252......251
.500......287......281
.550......302......292
.600......310......298
.650......317......N/A


EXHAUST #'s (w/ pipe)

.200......116......112
.300......171......170
.400......204......203
.500......222......221
.600......232......230
.650......237......234

Should have provided you guys with this info sooner....sorry bout the delay.

We have shipped a handful of them recently and I expect you will be seeing some dyno results over the next few weeks.

This head is ideal for any larger cubic inch small bore strokers (383, 395, etc.) and "aggressive" stock displacement builds with notched factory or aftermarket pistons, 230+ duration, and an owner who is OK turning his factory (or aftermarket) shortblock 7000-7200 RPM's...more with the added high RPM reliability of a solid roller set-up. Rodbolt upgrades a good idea even with a hydraulic roller cammed 7k combination.

Also, I highly recommend our 8019 spring upgrade to anyone using this head as undoubtedly the higher RPM and heavier valve (2.080 Int) will induce valve float. Our 8019 spring is made of the same proven, durable material our standard spring is made from but provides 15-20 lbs. of additional seat pressure and about 40-50 lbs additional "over the nose" depending on net cam lift. These springs are excellent and I have seen rock solid valve control to 7200 on the engine dyno with a hydraulic roller cam (with everything dialed in concerning pushrod length and valvetrain geometry).

Feel free to contact AFR if you have any questions....

Thanks,
Tony M.
(818)890-0616 Ext. 109

 

I'm very interested to see how Patrick's car does with these heads on it. Nice numbers on a 3.900 bore. Should make some good power.

 

I asked AFR to send me a flow sheet of my small bore 225s after they were milled to 59cc. Suprisingly, they're almost identical to the 65cc numbers Tony posted above. I guess starting with a small bore chamber means that milling doesn't hurt the airflow much. Not sure if that's true with other heads on the market, but the AFR small bore 225s flow incredibly well in a 3.900" bore even after they've been milled.

 

Tony, congrats on getting your new 225 small chamber head out. The flow numbers look good. Can you tell us a little more about this head?
Intake runner volume
Exhaust runner volume
Intake valve free drop with 65cc chamber

Are you planning and engine dyno comparison with different cam shaft for this head?
We are looking forward to Patrick G #’s
Bob

 

Hello Bob...

Good questions for sure.

Intake and Exhaust volumes are virtually indentical to our current "large bore" 225's...

(Approx. 229 cc's and 85 cc's respectively)


Free Drop info as follows:

Stock LS6 head @ 65 cc's .160 (with thin margin, lightweight factory valve)

AFR 205 @ 66 cc's (PN 1510) .176 (a little more than stock offering additional P to V)

AFR 225 "small bore" @ 65 cc's (PN 1660) .114 (obviously a fair amount less than stock)

AFR 225 "large chamber" @ 72 cc's (PN 1630) .147 (close to factory spec)


Also guys, we are still wrapping up the ridiculously awaited "large bore" 62 cc version of our 225 head (PN 1610) which is ideal for any combo's with a 4" or larger bore and the need for less chamber volume for higher compression, smaller dome or dish pistons, etc. This head will probably have the least free drop of all the products we offer....I'm guessing .015-.020 less than our small bore 65 cc 225'. I will provide that information as well as the flow data as soon as that product is in production (hopefully soon....don't ask....LOL)


Regards to all,
Tony M.

 

Thanks Tony
Bob

 

congrats on getting the heads out tony

 

Tony,
Will angle milling these heads "to decrease valve angle" increase power numbers? What are your thoughts on using a lesser valve angle on the LS1 type head?

 

It would require a SERIOUS angle mill (alot of material removal) to appreciably change the valve angle of any 15' (stock) LS cylinder heads (not a feasible scenario). While a flatter valve angle is usually beneficial to flow and power production (I say usually because there are very few absolutes in the business of airflow and power production), other factors such as cross section, port and chamber design, valve job profiles, etc. play a larger role in determining airflow and ultimately power output. It's common knowledge that some of our competitors offer cylinder heads that deviate from stock geometry (valve angles, port locations etc.), and Im just as curious as you guys to see the results that a lot of the average Joe's produce by running them.

AFR set their sites on building an LS1 product line that consisted of extremely efficient "factory replacement" heads (everything in stock locations) which makes achieving big numbers in airflow and power all the more challenging....

As the LS market continues to evolve, so will we, and I'm sure you will see a product from us in the future that is aimed at the more hardcore among us, especially as that style cylinder head starts becoming more "mainstream" and recognized by othe vendors as well.

Tony M.

 

Tony,
Can we run the stock lifters and rockers with the 8019 upgraded springs?
Bob

 

Looks sweet. These would be great for the FI guys that want to stay with stock cubes.

Mark

 

what head should i put on a 402ci? 225 big,or small boar? does the big boar make more hp?

 

A 4" and larger bore combination will make more power with our large bore 225's due to less shrouding of the valves with the bigger bore diameter. Also, the low and midlift flow will be stronger due to the more "open" chamber design.

Only caveat there is chamber volume....we dont recommend milling the 1630's below 65 cc (66 or larger preferred) and the large bore small chamber 225's (AFR PN 1610) aren't in production yet.

Assuming you need a head thats 66 cc's or larger your in good shape.

Hope this helps...

Tony

 

Tony what is the wait time for a set of these small bore 225's I am sick of waiting for my ET's or is it about the same?

 

I think a few of our dealers either have them or have them coming....even direct would only be in the 4-5 week realm (realistic lead time).

Call me at AFR and maybe I can point you in the right direction...

Tony

 

I have a 395 all stroke motor and was wandering what size intake valves you had it these heads. I am currently using a LQ9 head with 2.08 intake valves and was wanting a little more. What size valves does yours come with?

 

thanks tony,that does help. i'm running the 205's now and can't waite for my 402ci w/the 225 head.

 

David...

Stepping up to a larger valve size will do absolutley nothing for you. A 2.080 is already pushing the envelope on a 3.900 bore. Going to a larger valve would just increase it's weight needlessly and cause additional shrouding issues with the small bore. Not to mention you would have to have the perfect valvejob and properly rework the bowl and short turn radius (which are very sensitive area's) to see an increase in flow, again assuming the shrouding wasn't an issue which it is in your case. Just installing a larger valve doesn't increase flow and in fact could very likely reduce it because the intake runner has been so optimized with the current 2.080 set-up.

And BTW, all of our LS 225's are fitted with 2.080/1.600 valves.

Thanks,
Tony

 

Do not waste your money. The 205's will work great with your future 402 IMO.

 

I agree....Great low and midrange grunt, excellent "tip in" and part throttle, and "stupid" fuel economy considering it's power potential. The large bore 225's will make more peak power (10-15 RWHP if I had to guess) and that is mainly due to the increase in low and midlift flow. The intake will cancel alot of the peak flow gains seen on the flowbench between the two (even a ported FAST 90 appears restrictrive when you cross 300 CFM's of airflow @ the cylinder head).

If you get a good price for your used 205's and want to put up the big #'s (at the expense of the few perks mentioned above), the 225's would certainly be a good route to take but don't rule out the 205's as the end results might surprise you. You can go one notch bigger on the cam with the smaller cross section of the 05's because the airspeed will keep reversion to a minimum. The extra 2-4 degrees of duration might get you closer to 225 numbers when the smoke clears assuming you do up the cam a notch.

Just some food for thought....

Regards,
Tony