Guys,

Alot of the old timers on this board will remember a thread I started back in 2011 (scary!) documenting a build destined for my C5 at the time (which I just realized is 6 years ago to the day today.....total coincidence!).

The motor was awesome but we had some issues on the dyno related to my pushing the envelope a bit too tight on quench and it caused me to take the engine apart and replace a single piston due to a slightly pinched top ring land at the time which occurred during one of the pulls (for the record I would never go into "unchartered waters" with a customers engine and I knew exactly what I was doing at the time and the risk inherent in doing it....my goal was to remove the carbon from the pistons which I accomplished in 7 of 8....LOL). If we had slightly more water temp in the engine I would have been fine....it was the one variable I didnt think about or consider. It wouldn't have happened at normal operating temps on the chassis dyno....the block would have expanded more with the heat and there would have been more room between the piston and the head!).

Here is the thread if you haven't seen it.....lots of pictures and great information. We made over 700 at the crank with what is essentially my MMS 250 cathedral head at this point

https://ls1tech.com/forums/generatio...ker-ready.html

A few things happened after I returned to the dyno....the one major thing being I was never ever able to duplicate the numbers from the first session. I mean I missed them by 20 HP.....not by a few ponies. It drove my crazy....I actually took the engine apart and swapped lifters as it was the only thing I changed when it came apart to replace the piston. Went back to the dyno and made the exact same power.....it was no slouch at 711 HP and 650 ft/lbs of torque but the big numbers you see in that thread (730+) I'm forced to chalk off to a dyno anomaly not being able to duplicate them. I did puff hone the block when it came apart but I can't say whether that contributed or not. It will remain one of the great unsolved mysteries in Mamo's life....LOL (At the time I stressed over this far too long....six years later Im over it!)

For the sake of this thread (discussing the rebirth and subsequent dyno test of this engine 6 years later), let's just call the baseline configuration with the cathedral heads 711 HP / 650 TQ. However alot of things have changed since then....I no longer head up the R&D dept at AFR (as most of you already know) and I have been steadily working on my own line of MMS products (Mamo Motorsports) for the last three years or so. In fact one of the most popular new products I offer (and a very successful one) is my new MMS 265 LS7 head. This product has done extremely well out in the field setting numerous heads/cam C6Z06 records on independent dynos across the country when coupled with other products I also offer for that platform (there are dozens of threads on the Corvette forum if you care to look....Google MMS 265 and you can read more about them and see alot of build threads highlighting their results). These are the heads that now top the very detailed shortblock you saw in the thread linked above from 2011....a much more fitting head for this type of displacement as most would agree.

The cam specs are very similar....compression is about the same (mid 12's), but we have a new top end consisting of MMS 265 heads and a Mamo ported MSD intake with mt Stealth top upgrade (all the logos removed to look more stock). The TB is literally the same (with my fabricated radius inlet) and the vacuum pump IS the same (GZ Motorsports Sportsman line). Even the rocker ratio and lift is the same (1.8 for both).

Thought it would be fun for you guys to guess the new results with the new Mamofied LS7 top half versus the former Mamofied cathedral top half. Basically I pulled the engine apart....inspected it....ball honed the cylinders with a 400 grit hone, and reassembled it with the same pistons, rings, etc. It has an FBody wet sump pan now versus a Vette pan (this motor project was resurrected due to a local customer expressing interest in purchasing it....it's going to be installed in a 4th Gen FBody now).

Cam specs (almost identical on the intake with the appropriate split on the exhaust for the square port configuration). Most would argue these specs are "light" for this much displacement and I wouldn't argue. I was looking for the have your cake and eat it too scenario....big power in a user friendly combination. This is a street engine first and a drag engine second.

Cathedral engine........251 / 255 @ .050 114 + 2
MMS 265 LS7 build.....250 / 264 @ .050 113 + 2

Ported MSD vs heavily modded and ported FAST 102

Yella Terra rockers on both (1.8 ratio .675 ish lift).....limited travel HR Johnson lifters on both....same dyno headers with a 24" 3" extension after the collector (1.875 primary pipes....no mufflers behind the 24" extension)


To make things more interesting while having all this fun I'm going to offer the winner of the "Dyno guesstimation game" an MMS Tshirt, MMS hat, some quality decals, and 10% off any purchase good for one year so if you were thinking about buying some product from me in the near future put up your best guess!!

It will be a very simple tally system.....if you miss TQ by 10 and HP by 5 your Delta is a "15" adding both together. The guy with the lowest number wins! In the event of a tie I will offer the same MMS paraphernalia and discount to all parties.

I will announce the results Sunday night.....about 6PM my time....9 PM EST

The cutoff is basically anyone who throws their hat in the ring with numbers prior to my posting the results!

Just realized I should share some pertinent info regarding the heads (the major variable here IMO). The cathedral heads flowed about 360 CFM on the intake and 265 ish on the exhaust with a 250 cc runner. My new MMS 265 LS7 heads flow 410 CFM on the intake and 265 ish on the exhaust with a 265 cc runner (which is actually 5 cc's smaller than an unported OEM LS7 head that only flows 368 CFM.....it's a reeaally efficient piece).

Here are some pics of the engine going together in my new shop (another improvement since back then!)



















If you guys have any other pertinent questions feel free to ask....this thread can be more than a guessing game also btw....anything tech related to the topics being discussed here is fair game also. Man time flies....I cant believe it's been six years since I drafted that first Vader thread....it really is insane how fast the years fly by!!

OK guys....will be checking in on this thread fairly regularly to see whats happening. Im sure there are some details about the engine I omitted that might be of interest. The engine dyno is naturally the same (Westech).....no variable there at all



Cheers,
Tony

 

748 HP @ 6800 RPM
664 lb' @ 5400 RPM

 

749HP @ 6800RPM
665LB @ 5400RPM

Is my guess





LOL

 

810 hp 670 tq

 

773hp / 685tq

 

751/702

 

760hp/680tq.

 

775/695

 

762/690

 

761 hp
699 tq

 

773/665

 

835hp/740tq

 

I was going to ask you how much more he would make with TFS 245's but decided to guess 1 more hp then you did

752/703

 

Ill try 783hp/672tq

 

772hp/674tq

 

I know Darth found out his short block was cracked the other day. This build wouldn't be for him would it????

 

The throttle body looks bigger than the crank pulley lol. 695/680

 

LOL, No. Funny coincidence, though...

Tony named his old C5 Darth Vader a long time ago. I picked my username looking for something that ended in "-ator" so I could use "8r", and the cool ones like "XLR8r" or "Devast8r" were taken. I stumbled onto "Darth". I didn't even talk to Tony until a year after I joined the forum. When I found his old "Darth Vader your stroker has arrived" thread, I laughed. The two names are total coincidence.

FWIW, I think 800/720 - 50 extra CFM of air is hard to ignore...

 

788/670

 

Awesome motor. Cant wait to see what it does.

789hp/668tq