Finally had a customer just test a set of ported 205's I optimized and went thru for him a few months ago with no other changes. I have helped a number of people on this board with the exact same mods and the key to this work is focused in the chambers with some light porting and refinement done in the ports. This highlights more airflow without more port volume adding even more airspeed and efficiency to an already very efficient design.

Its been a popular mod on a handful of 346's, a few 6.0 liter's, and a handful of medium sized strokers as well (383/402/403 combo's). Most if not all of these combo's have produced above average results when the rubber finally hit the rollers (all of them with amazing throttle response as well). It really works well with the larger bore stuff taking more advantage of the unshrouding I do in the combustion chambers but as evident by these results is still very effective on a 3.900 bore combo also. The graph below is an F-body with a mild 383 and a smallish 234/238 camshaft (very street friendly). I have normally been quoting 10-15 HP based on the gains I have seen on the flow bench which certainly looks inline based on the results seen below. I would say a 4' or larger bore motor would reap even a few more ponies from the better matched cylinder wall to combustion chamber transition and additional airflow the larger bore unlocks when the same head is placed on a larger bore fixture on my flowbench.

Note the head was 1-2 cc's smaller after I did the work and milled the deck, so the motor did have a couple of tenths higher static CR. Also, this was not done on the same day (almost a year apart actually) but per the customer the weather and conditions were very similar (same dyno and shop which was New Era Performance). The big news, IMO, is the area under the curve. It simply looks like a larger motor was tested by the way the increase in torque is available immediatly (much like a stroker would offer) and carries even larger gains in the middle with an 18 RWHP gain at it's widest point. Discounting a few ponies for the small CR bump, still a very effective gain from the work performed.

Most of my other customers have incorporated this work with alot of other changes....cams, ported intakes, sizable compression and/or displacement increases, etc.....so this is kind of a unique glimpse of what the bulk of the gains from just the head work is worth which a fair amount of you have inquired about. Previous to this I just quoted other package results that were similar and the 10-15 HP my "air dyno" told me it might be worth....LOL

Enjoy....

 

Tony,

are these changes going to be made to the cnc machine so that all 205 heads will incorporate these changes and be more efficient out of the box?

 

Thats a very good point and something I should have clarified a little better...

The reality is as good as our CNC programming is (and anyone else's for that matter short of some ultra exotic programs found in the one off big dollar stuff), in a production environment there will always be room for more in the hands of a very capable cylinder head expert. The fact I designed the original prototype enables me to know exactly what area's to finese that might be sensitive to flow and respond with some gains. Basically, I take a reeaaally good CNC piece and I perfect it essentially all by hand. It would be impossible for a mass produced piece to be as perfect as I could create/refine by hand.

Some of the gains related to this work will in fact be incorporated into some new products that are a few months away (our all new 215 LS head and finally the completion of our big boy which has grown from 235cc's to 240 which will be its moniker). Both of the new heads are cathedral style ports and neither is six bolt (before you ask) which is really a perk that few of you actually need (you have to be over four digits to the tire before a four bolt head will start to give you long term reliability issues). But even those heads massaged by the guy that created the prototyper they were digitized from would see small gains from "blueprinting" and some fine romance work with the grinder. How much time do you think is invested in a head destined for a NASCAR engine or the like. Countless additional hours looking to romance and optimize the last few precious CFM.

This work isnt for the average hot rodder....its for the guys that are looking for every last ounce they can wring from their engine (and are willing to pay the premium to get it).

Hope this clears a few things up for you guys....I knew as soon as I hit send I probably should have included a paragragh or two touching on this....LOL

-Tony

 

OK I'll take the lead. How much extra does this romancing and massaging cost and or is a "sale" or economic stimulus from AFR a possibility soon??

 

Good luck on that....

You know what they say....if you have to ask.....LOL

Seriously, PM me for more info but anywhere between $750 and $1000 depending whether we are starting with new or used castings.

Not cheap but then again decent value looking at the graph/comparison above.

The reason I posted the info is because I get PM'ed once a week or once every other week from a guy looking to quantify the difference....till now it was all specualtion and "look what this independly built and tested similar combo made" etc.

-Tony

 

Great info Tony thank you for taking the time.
I am looking to install one of your AFR heads on my LS2 A4 with 3:73 gears. My goal is to have a fast NA car that can pass emissions.
Question on your new LS 215 head a few months out, will the intake valve size increase too?
What will the trade offs be with the 215 vs the 205?

 

Not much....on a 346 a 205 would still have better tip in and part throttle response....a good choice for a guy in a 224 cammed combination or smaller.

With a 6.0 or larger engine the 215 would be a more natural choice....a little larger cross section and more flow to feed the inches. It will have similar flow figures to the 205's I prep by hand with a slightly larger cross section and a little more peak flow as well. Great head on a 364 up to a 418 or so....even an aggressive 346 as well. Very versatile piece as is a ported 205 which has worked fantastic even on 400 CID strokers still making big power upstairs which somewhat goes against conventional wisdom with the smaller cross section. Its just that it has such good area under the curve and so much airspeed it gets those cylinders packed better than the flow numbers alone might lead you to believe (not to mention alot of number tossed around the net are BS anyway).

There's alot more involved in a truly great head than reading a flow chart in various magazines or catalogs could possibly clue you in on....it's just one piece of the puzzle as they say and thats assuming all the numbers are legit which is the first flaw in all the "assumptions"

-Tony

PS....I have helped a handful of low 240's duration 402/403 strokers make low/mid 500's to the tire with a 305 CFM small port romanced 205.....on paper most shops/individuals would tell you it cant be done....but it obviously can and its all about the package and the rest of the details surrounding the head and total combination. Makes for brutal torque and responsiveness which I personally love in a street car.....waaaaay fun if you can hook it.

 

Here is a build similar to what you descibe wanting....you should try and copy this as much as possible. Scroll down aways to see the dyno graph. This was with a conservative tune with the tuner (Tom Wong) knowing it would be in a road race application usually seeing a fair amount of heat. Thru a stalled auto these are solid numbers for a mild 6.0 build...I know the customer is very happy with the power and overall tractibility of this combination. It basically drives like stock but has alot more power

http://forums.corvetteforum.com/c6-t...-425-rwtq.html