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565 inch Mamofied AFR 300

23K views 105 replies 35 participants last post by  90lxracer 
#1 · (Edited)
To begin with it is a given that my choice in cylinder heads for this 565 was a dead miss. I wanted to keep the Dart 4500 oval intake from my 500 incher to use with these 300's. Once committed there wasn't any turning around because the money had been spent so with Tony's help on the cam spec's the project moved forward with some serious speed bumps in the machine shop area as many of you already know. My brain fart didn't help when I degreed the cam 4* retarded from where it should have been. I still don't know how I missed it but I did so I own it. :sad:
So with the undersized cylinder head we still managed to produce a satifactory result given my goals. It is a given that with a larger cc intake runner such as the mamo 360 piece the results would be much better than they are. It's also a given that with an electric water pump and a "race style" oil pan along with a more efficient vacuum pump the existing combo would have produced a few more ponies than it did but these are the results with no more than a valve adjustment, the swapping of distributors due to errant timing and a couple timing changes where we found that there was no power difference between 30 and 35* timing.
 

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#2 ·
Gonna be a lot to handle that's for sure.
 
#3 ·
Dan, buckle up and hold on tight, you are in for one wild ride !:thumbsup:
 
#6 ·
Those numbers aren't bad and it still went to 7100 rpm. I bet you have fun with it.
 
#27 ·
You of all people know this data is correct. Best of all, Dan's 66 Chevelle is more that capable of backing up the numbers at the track.
 
#8 ·
That motor could be deadly consistent bracket racing Dan. That cam really moved powerband up more then most would have speculated.

Glad for you that it is together and healthy.
 
#11 ·
Nice, good to see everything appears to have worked out Dan :beers:
I am thinking those 300's are no longer 300's :D
 
#12 ·
Thanks for the kind replies guys. This build was more than a headache for me and took a while and some tweaking and remachining to get here.
Mike, to be clear, these are heads which Tony Mamo ported and are not typical 300cc production pieces. The production heads don't flow 405 cfm on the intake nor do they flow 325 on the exhaust side which is a near 80% IE ratio. There were several things I wasn't happy with the first go round so I made a piston and ring change and a slight cam change which more suited the 80% IE ratio. Tony and I decided to go to near straight up on the intake/exhaust lobe as these heads son't require the split of a larger cc intake port.
So again, these heads were not the correct choice for this displacment but sometimes a little head can go a long way.:)
 
#13 ·
Yeah,, that is kind of what I was getting at I knew these heads had Tony's handiwork involved,,
Not the results that are going to be seen with the standard AFR 300's by a long shot
Really nice job, glad you got the results you were aiming for I know it was a bit of a long road,,,,, :beers:
 
#14 ·
Guys,

Thought I would chime in quickly.

This engine has been a long journey for Dan.....after initially testing some six months ago with "OK" results, it was evident the torque was lower than it should have been even though the power at 850 HP or so was inline with what you might expect from such a small head. The motor simply carried better than you might expect so the power was there in spite of the torque being down quite a bit (I told Dan it looked like the curve of a good 520 inch engine....LOL).

Also....I told Dan time and time again (he will vouch....LOL) I never expected much more than 850 - 875 HP from these heads (still a significant number really) but we all suspected that there may be potential issues with the shortblock (it was obvious something was amiss with the lower TQ #'s) and after sleeping on it awhile Dan decided to tear back into the engine and see what's what, which clearly turned out to be a great move. I wont go into all the details but after swapping pistons and us running an even smaller cam than the previous grind (less exhaust lobe which I felt would help the TQ some and we didn't need to crutch the exhaust that much with an 80+ % Exh to Int ratio), the power curve of the new motor is off the hook. The thing that looks different to me due to the smaller head moving air at a higher rate of speed earlier in the curve is the lead in TQ.....its close to peak a thousand RPM's before it gets there and carries extremely flat and extremely well helping to finally net the 900 ponies Dan ultimately achieves.

I have seen higher peak TQ figures from high compression 565's (from the additional airflow of a larger head) but what surprised me is how well this engine carried the torque it made.....it just goes against conventional wisdom somewhat with the head being obviously far from ideally sized for this combination

My hat is off to Dan.....I couldn't be happier for him as he really went the extra distance in an effort to make things right and I'm glad it paid off for him and he got the number I doubted was achievable with this combination (the "900 " figure), and whats funny is there is more lurking here with some of the other items mentioned (a better kick out pan versus more of a street pan for windage control, EWP to free up a few ponies on the dyno etc.).

For those who prefer to look left to right to appreciate the sexy curve of this engine here you go!



Regards,
Tony

PS....Wanted to mention the manifold on this engine which was/is a critical component to the final results, was ported by the late Roger Helgesen not long before he got too sick to do any more porting work. I kind of felt his presence in the dyno cell yesterday as I looked at the intake manifold and big Dominator carb cooling off after the pulls we made still somewhat surprised by the end results. If there is an afterlife he was certainly smiling as well.....Roger and Dan were good friends btw and everything worked out in such a fitting way.
 
#17 · (Edited)
Its pretty much 900 HP from 6700 - 7100! :thumbsup:

Like I said, very surprising how well it hangs on and the big power is in early and carries beautifully (no fast roll over here).

Didn't touch the openings at all.....its the exact same size as the OEM CNC program I designed for AFR.....most of the work is in the bowls, chamber, and valvejob as well as the cuts on the valves themselves

The later model "roval" design has a much better cross sectional area (and shape) than the original oval port design from the 60's and 70's and is the main reason I went with it in spite of the limited manifold availability in out of the box as cast pieces (most have the old shape).....I just felt the newer design lent itself to much better performance and there is no better proof of that than this particular engine which is likely the highest output N/A I have ever seen recorded in the oval port line-up

This engine is going to be absolutely wicked in the car.....it will take throttle nobody's business and I'm quite confident the power and brutal responsiveness is going to scare the **** out of Dan for a good while.....LOL

I have helped numerous customers with reworked 265's, 290's, and 300's and they ALL comment on that same scenario I just highlighted. One guy lost a rod bearing cause he cant help himself and always shows off at the car shows by zinging the engine in neutral....he says it revs so quickly it sounds like a flat plane crank Ferrari engine.....LOL

-Tony
 
#20 ·
I guess I should start building a 565 for my 300s! No doubt it would crush my little 468...great result....congrats on making it to 900!
Thanks Anthony, I'd suggest not doing a 565 with these heads despite these results. This is a less than optimal build to be sure. You could always send those heads to Tony for a refresh and do a 505. The 300's really are too small for a 565 but I do encourage the average guy like myself to do some hands on engine stuff. It sure beats watching TV. I guess it depends on your goals in the end. It was a lengthy endeavor for me. Once into aftermarket parts one learns to appreciate those who do this stuff for a living. Factory stuff is fairly straight forward and the aftermarket is not for the impatient. It can make you crazy but step on in and learn some things while you still can. At a point we'll be forced into mass transit. :(
 
#21 ·
Dan, great combination. Welcome to the "It doesn't fit out of the box?" crewl:), but you probably knew that already.
 
#22 ·
Mike, Tony has told me since the beginning this combo is all wrong. He may be correct but even he is happy with the results. I know he worked hard to accomodate my insanity. He has been spec'ing some winning BBC and Ls type stuff for a while now. I think Mamomotorsports is going to be
a first thought company for many folks trying to improve their performance. I know a few who will vouch for that. :yes:
 
#23 ·
It can't be wrong, if it's so right.:thumbsup:
 
#24 ·
Well done Dan. :)
Your power-per-cube is a tad better than mine with these same heads. (1.59 vs my 1.54)
Not sure how much port work was done, and being aware of other differences in our combos, I'm still impressed that your torque and power peaks are still around the same as mine while feeding an additional 105 cubes.
Again, well done, and 900 hp engine in a street car is nothing short of a Mother Fxcker. :D :beers:
 
#26 ·
Congrats Dan!

I know that this has been a very long time coming. I'm glad that you made sure ole Tony "earned his keep" on this build. I hope everyone who reads this thread appreciates what you folks accomplished on a very legit dyno. I have some very recent experience (last week) with the Westech SF 902 engine dynos and I can tell you first hand that they don't cut you any slack what-so-ever. Your HP and TQ numbers are as real as they get.

Hope to see ya soon. Take care.
 
#28 ·
Congrats Dan!

I know that this has been a very long time coming. I'm glad that you made sure ole Tony "earned his keep" on this build. I hope everyone who reads this thread appreciates what you folks accomplished on a very legit dyno. I have some very recent experience (last week) with the Westech SF 902 engine dynos and I can tell you first hand that they don't cut you any slack what-so-ever. Your HP and TQ numbers are as real as they get.

Hope to see ya soon. Take care.
Pat I was wondering about your pump gas producer 565 and how I could get around that one. As I recall you still whooped me on the torque but needless to say your 565 is impressive as hell. Just two different approaches to a goal. Long term you will get off for less on fuel. Ratt Vette John has been burning up my ears with crap like e85 lah blah blah. He will be back in the game soon with his new vette. All I can say is that using e85 is one more learning curve to deal with. I greatly appreciate what you and Saiki get done because you put the numbers down at the track.. readily.This stuff can be fun.
 
#29 ·
To begin with it is a given that my choice in cylinder heads for this 565 was a dead miss. I wanted to keep the Dart 4500 oval intake from my 500 incher to use with these 300's. Once committed there wasn't any turning around because the money had been spent so with Tony's help on the cam spec's the project moved forward with some serious speed bumps in the machine shop area as many of you already know. My brain fart didn't help when I degreed the cam 4* retarded from where it should have been. I still don't know how I missed it but I did so I own it. :sad:
So with the undersized cylinder head we still managed to produce a satifactory result given my goals. It is a given that with a larger cc intake runner such as the mamo 360 piece the results would be much better than they are. It's also a given that with an electric water pump and a "race style" oil pan along with a more efgficient vacuum pump the existing combo would have produced a few more ponies than it did but these are the results with no more than a valve adjustment, the swapping of distributors due to errant timing and a couple timing changes where we found that there was no power difference between 30 and 35* timing.
As long as you hit your goal that is all that matters. Now get to the track
 
#31 ·
Really do appreciate the kind replies folks. I'm just happy as heck my home built junk lived through those pulls. Thanks again to Mike Lewis for answering some clearance questions I had early on with this engine. That is greatly appreciated as well as the usual help from Rod at Isky. He was very instrumental in these new numbers. The EZX lifters are excellent.
On the first session when the torque numbers were down, Mamo and Brule' said right out of the gate that something was amiss in the bottom end. Although it made 854hp then those two were focused on the less than optimal torque results and going home with that in mind I found it troubling enough to pull off a head and do some looking. It was glaringly obvious that although I was charged for the torque plate hone it wasn't present in the bores. You could see excessive wear in each everywhere a headbolt
went that was adjacent that hole. That wear transferred to the pistons so I tore down the entire assembly and found several "anomolies" I wasn't happy with. For years I used the same machine shop and never had a hiccup. Everything was always as it was stated to be by the machinist. When he moved up to Oregon I was without a machinist so upon recommendation by one of our members with a damned fast racecar who had used him I went that way. Would never do it again though.
As it was, I also found that by a brainfart on my part I had installed the cam 4* retarded. In an attempt to help the less than desirable torque number the exhaust lobe was shortened up to better accomodate the stellar exhaust port on these 300cc ovals. Still maintained the 112 lobe spread which performed excellently.
So what I did was have Ross make another set of pistons and this time went with .043 rings and low tension on the bottom. I sent the vacuum pump back and it was checked out, tightened up and while still less than optimal it made 8.1 inches at peak rpm.
All in all what was learned from the first debacle caused a few tweaks to be made which cumulatively ended up where we are. I am the first to admit I'm a novice at this but if you never try you never get anywhere.
Moral of the story is never "assume" anything and "trust but verify" machine work and choices of parts.
 
#34 ·
I can't recall who, (possibly Mark Jones?), once said that an obvious sign of a bore not being honed with the torque plate was excessive wear along the head bolt holes. The bores must STAY round after the heads are installed. Good job Dan.
 
#37 ·
Tony,

I would be interested to know the following in the AFR 300s:
1. How you finished the valve guides and to what spec.
2. Run out for Intake and Exhaust
3. Shape of valve seat cut angles
4. Bowl, tweaks
5. Chamber tweaks

This would help us regular folk when working with our machinists,
builders, and porters.
 
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