oval port AFR head 565 BBC

[grumpyvette]

For starters, I realize that my choice of cylinder head is not the optimum choice of heads for the displacement of this build. Having the roval headed edelbrocks on my car now and having used a very small hit of nitrous along with a flat tappet cam that was never intended to run any nitrous I came to the conclusion that I'd like the equivelant power on an n/a basis so I decided to try to put something together without re inventing the wheel. My goal has been to retain the induction system I currently use and magically afr comes out with ad's for a 300cc roval port head. Since this head uses the same intake entry as my current head it made sense to go that route. I thought I'd build a 505 and be done with it. I was having a tough time finding a mkIV block and when you add up all the required work to make it useful you're out a coupla bucks so I decided to go with a big m. Well that turned into a why not go 4.600 bore even though it's big for the head. My goal is to footbrake the car so I thought I might replace the torque of the nitrous with displacement. So here I am at this point. I made a mold of the afr300 chamber, sent it to Ross Pistons and here we go with enough parts to start the process. I received the pistons today. I spoke with Jason Pettis yesterday about machine work and decided to let him do the job. He came highly recommended by a few of my friends who have used him, 69 Ratt Vette being one of them.

As stated some months ago I asked Tony Mamo to mamofy these heads and he produced some respectable flow figures for me considering how small these ports are. He ended up at 405cfm@.700 and 320cfm@.700 respectively without getting into the incrementals overall. I believe I have posted the complete numbers in a previous afr300 thread.

The Camshaft.... I cannot say enough how pleased I am with the folks at Isky cams, particularly Rod for helping me get a cam made for this build. The cam spec's are likely not something that would be suggested here by our resident cam gurus and Tony mamo told me he thought he was going to throw up when I told him the numbers. lol
I have a friend, Roger Helgesen, who attempted to assist me with this selection but in the end I personally made the choice. I think I was sitting on the can when I decided. The cam will be a gross lift of .805 intake and .748 on the exhaust, duration is 274* and 278*@ .050 . I am using the Isky .905 EZX Lifters and the cam is ground on a 110*lsa. I'm also using T&D 1.75 and 1.7 shaft rockers. I am not building this to compete with the pro engine builders we have on the net and am certainly not expecting to place anywhere near the power figures that are posted. At this point I don't plan to run a vacuum pump or an electric water pump or electric fans, etc. I also plan to use the current 7320 Dominator that is on my 500 incher. I'm thinking that because my headers were custom built for my edelbrocks that I may have to buy another set of headers but will cross that bridge when it comes. So this is the plan and it will take some time to complete but after what seemed the longest wait in history I feel I can make some progress. Here's a photo of what I think may be the first set of custom pistons for the afr300 head. Keep in mind I chose
1/16th 1/16th & 3/16th rings because I want this to last a while.
Dan

FINDING A DECENT BBC CAM ON A TIGHT LSA , THAT BREATHES WELL AND GIVES THAT OLD SCHOOL RUMBLE AT IDLE,CAN BE A PROBLEM AT TIMES< HERES A FEW
http://www.claysmithcams.com/big-block-chevy-11/

Guys,

Would have been here sooner but I have been really busy lately....I know....quality problem!

Anyway it has been fun working with Dan.....he is a good guy with a great sense of humor and he didn't pay me to say that!

Let me touch on some of the things that were brought up here....I guess first and foremost I would admit that I would have encouraged Dan to move into a larger head on this combo (and I'm a fan of slightly smallish efficient heads on large motors....this one pushed that a little too much IMO). To be honest I have a really kick azz 325 cc (finished volume) custom program that flows close to 420 CFM at .700 lift (409 at .600!)....that would have been the cat's meow on this displacement if you were looking for an "explosive type" combination that could still lay down a BIG number (875+ on this combo easily with the right cam).

That being said Dan was intent on doing something different....max power wasn't really his primary goal (if it was he would have taken my advice on the cam!)....he wanted something really fun to drive that while still making a respectable number would fry the tires at will....LOL Without a doubt this recipe will deliver....the throttle response of this engine is going to be something of legend! Yes....I would have cammed it with a little more duration and I would have ground it on a slightly wider LSA, both moves helping to hang that higher RPM torque curve out a little longer (bringing more HP to the table)....a situation that is more important on this combo due to a head selection with a cross section that will tend to want to force the torque curve down as the piston speed and RPM get up there.

This is an interesting combo though and even with a cam that wont quite exploit all it has to offer in a combination most might casually overlook and dismiss on the notion it doesn't have enough cylinder head, I think the numbers will still be respectable (I'm guessing it will fall somewhere around 800 HP), but the responsiveness and how quickly this torque curve crosses the 700 ft/lb mark on it way to 750+ ft/lbs will be very interesting. And there is nothing wrong with making big power early....its a much more visceral experience in fact if that is the case....just explosive to drive no matter where the tach is.

BTW, the reworked 300 is an impressive piece and Im stoked I was able to get a port that small over 400 CFM's (and do it at a very usable liftpoint)....I take a really good factory design and simply perfect it adding a few custom tweaks to the valve job profile, valves themselves, slightly rework the short turns and all the critical transitions....its an exercise thats far more detail oriented than relying on more brutish metal removal (and a larger port) to achieve the same result. Basically Im keeping all the "goodness" of my original vision and design and just really optimizing the crap out of it for lack of a more elegant description at the moment. It's up a solid 15 CFM's on the intake and if it poured 3 cc's larger than stock I would be surprised.....the exhaust is up 20-25 CFM for similar reasons (lots of detail work related optimizing) and minimal gains in sheer size.

Honestly if Dan were building a pump gas 565 for the street with a hyd roller this head would be the perfect choice and no excuses would ever have to be made. It would rip from off idle to a 6700 or so shiftpoint with the right grind (hyd roller). A 454 - 509 compression engine would be right at home with this head, but cam it up because you have all the airspeed in the world inherent in its design....its already "reversion resistant" and wont show the type of negative traits a larger cam with a large head would at a much lower RPM. Cam it deeper so it carries the torque longer and helps the "multiplier" that increases your horsepower

One last comment on the cam.....Dan's current choice I do not in fact "hate".....the first cam Dan had ran by me I wanted to take the heads back.....LOL I wont elaborate any more than that but suffice to say I disagreed with everything it was about and it would have hurt the power output significantly IMO. This current cam is just (IMO) a little light on duration because this combination would have thrived with a "crutch" of additional duration (due to the smaller head getting saturated earlier in the RPM curve). I would have added about 8 more degrees or so and widened the exhaust split a little as well.....opened the LSA to 112. Your not worried about midrange torque here folks....you want to help the top as much as possible in the cam selection. Look at it this way....if you would normally run low 280's @ .050 in a high compression 565 (kind of a general figure you see alot on the better running high compression mid 500 cube engines), this of course with a rectangular port more "conventionally sized" head, the smaller port would have liked and tolerated a little more. Dan's current choice is light for a conventional scenario with a head more proportional to its displacement, and lighter yet for a head that will have this engine rev like a light switch.

Alright....that's a mouthful for now. Im really curious what this engine makes and sounds like on the dyno.....Im sure it will be a thrilling and fun engine in the car.....perhaps down the road Dan will decide to experiment with some more parts....it certainly wouldn't surprise me (Ive got a custom 325 head with your name on it Dan....use the 300's on one of your smaller engines!)....that or go with a peaky 565 and a Mamofied all out optimized 357 and let er eat upstairs.....aka Jon Rutledge style! (72BBMonte). Which is still not a BIG head on a 565 with alot of compression.

Got a phone call today that kind of surprised me. The guy on the other end was Chris L from Ross pistons. He is the guy who used my chamber mold to make the pistons for my AFR 300 roval heads. The purpose of the call was to see how well the pistons worked out. In my experience there have been very few on the manufacturing end to call and ask how their product worked out for me. I am very pleased at this sort of customer relations from a manufacturer as it doesn't happen every day at my mere sportsman level. Tony Mammo is another who comes to mind who would do this sort of thing and it is appreciated.
I sent my block to Pettis Performance for machine work and lifter bore bushing for the .904 EZX lifters as well as the final finish on the cylinder walls. Since he needed the pistons to final hone the block I asked him to do the final contour on the domes as well. Here is a quick shot of the dome from the top. If you saw the piston I posted in an earlier post you'll see a bit of a difference in finish. I'll post pictures of the block later.