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680RWHP LS7 MCSS now the most powerful NA stock shortblock LS7 @ 700+RWHP!
Needless to say that I have a very big grin on my face for finally achieving a goal that I set out for myself long ago…..and the final numbers are in, 704/545 SAE RWHP/RWTQ for my 1988 LS7 Monte Carlo SS! I have posted my previous best results using the same Beck Sheet metal intake and NW 102mm TB at 680/540 SAE RWHP/RWTQ. And just for reference, when I started my horsepower assault the baseline crate motor numbers were 487/468 SAE RWHP/RWTQ! All three of these runs are compared below:
So what did it take….I switched out my Greg Good cylinder heads to a very special set of hand crafted GM LSX cylinder heads ported by Darin Morgan that he made for the Engine Masters Competition but never entered them in a competition. These are likely the best flowing GM LSX LS7 heads on the planet as well….here are the numbers from Rehr Morrison’s flowbench:
I also changed my rockers from Jesel to Crower at Darin’s recommendation and these heads have 2.25” intake and 1.60” exhaust, both Titanium for the ultimate high RPM lightweight valve train, especially when combined with the super small 1.300” PAC 1335 springs with a plenty stout 860 lb spring pressure open. Darin also perform some special welding on these heads to help minimize valve train deflection and a side benefit was enabling me to up my pushrod size from 3/8” to 7/16”.
There was a minor miscalculation made when the heads were being final milled and they were cut to ~59.2cc’s which inadvertently bumped my SCR from 11.79 to 12.78 which I know likely lost some CFM’s but the trade-off came back in the form of added power due to compression gain. The only other downside here was that I was previously running straight 92 octane pump gas at 11.79 SCR whereas now I added a smidge of Torco, just to be safe! I didn’t change my tune at all as far as timing and actually backed out 8% fuel above 5500 RPM at WOT.
And for all of the doubting Thomas’s out there who never believed that someone could build this powerful of a NA motor using a stock LS7 short block, single throttle body and pump gas because the chassis dyno that I used must lie let me tell you that Darin ran these heads on a 431” LS7 motor with a smaller hydraulic cam that mine with 11.5 SCR and it made WELL over 800 FWHP on an engine dyno (I’m not sure if Darin wants the exact number published so I will respect his privacy and leave the number at 800+).
I am also VERY pleased to say after MANY months of frustration and several very fruitless trips to the track this past year I finally resolved my WOT speed shifting problems where with the help of several Forum Members we determined that the Torque Management settings for the E38 PCM were limiting throttle position to 35% after each quick shift (meaning that if you shifted less than 1 second between shifts you wouldn’t have a problem but any quicker and you would have to fully let off the throttle before you could go WOT again!). And with this solved courtesy of the chassis dyno where I could validate the fix I did actually have the opportunity to take my car out to the track last month at Pacific Raceways in WA State! I am embarrassed to say that between a tool box, ¾ tank of gas and several other weigh adding measures like larger radiator, exhaust, etc., my actual drag-strip weight with me in the car was a very portly 3850 lbs.!!! As I suspected, I only got one shot at a full run through all 4 gears before I got called out and promptly booted from the track….the one and only full throttle through all the gears pass was a 10.79 @ 133.75MPH with a 1.76 60’ time. I was using MT 295/45x17 DR’s and launched at only 4000 RPM to ensure that I wouldn’t break anything and actually be able to get in at least one full pass since I have taken so much crap from so many people for not actually being able to run the car WOT at the track. The only real disappoint was the video camera wasn’t working for the 10.79 pass but I was able to convince the track owner to let me make a couple of 1/8 mile passes to back up the 1/8 mile MPH so that the Doubting Thomas’s wouldn’t call me out again and say that I never backed up this pass and at least these are on video so that you can see and hear how the car runs. For some reason the car was running excessively rich on the 10.79 pass (actually billowing black smoke) and you can still see evidence of this on the video of the 1-2 shift run afterward. I suspect that the car may have been running on the cold-side since I was having problems trying to keep the car cool in the staging lanes and elected to keep shutting off the motor and run the electric fan to keep the water cold.
To recap the car has a Son of Transzilla T56, RPS BC3 clutch and Moser 4.11 12 bolt. The full motor spec’s:
• 100% stock GM OEM LS7 crate short block
• Solid Roller Cam by Bullet Racing Cams
I just decided to do a new cam and quite interestingly I decided on an
LSK intake 259 with .663 lift
LSL exhaust 274 with .624 lift
It will be on a 109icl with a 113lsa
I put your cam specs at .050" in to see how it stacked up to yours after I ordered it and amazingly enough it is almost dead on at .050"
Mine is Hyd, but I am hoping it will help to better my current 10.38 @ 127mph. My truck weighs less than your car (3,200 with me in it) but Aero is horrible. My previous 1/8 is right at 106mph.
I hope to see more track passes from you in the future.
Congrats John! Happy as all get out for you! I knew when you recieved the heads, it was going to be a slam dunk for 700 wheel. Darin is a master no doubt.
Your ET could be so much more impressive if you cut the light and not wait to see green. Go in the middle of the last yellow. How much does that car weigh with you?
Your ET could be so much more impressive if you cut the light and not wait to see green. Go in the middle of the last yellow. How much does that car weigh with you?
Cutting a good light does not improve et, only reaction time...
Your ET could be so much more impressive if you cut the light and not wait to see green. Go in the middle of the last yellow. How much does that car weigh with you?
PER THE POST ABOVE
"my actual drag-strip weight with me in the car was a very portly 3850 lbs.!!!"
I just decided to do a new cam and quite interestingly I decided on an
LSK intake 259 with .663 lift
LSL exhaust 274 with .624 lift
It will be on a 109icl with a 113lsa
I put your cam specs at .050" in to see how it stacked up to yours after I ordered it and amazingly enough it is almost dead on at .050"
Mine is Hyd, but I am hoping it will help to better my current 10.38 @ 127mph. My truck weighs less than your car (3,200 with me in it) but Aero is horrible. My previous 1/8 is right at 106mph.
I hope to see more track passes from you in the future.
Awesome, good luck!
Where did you get / have your headers made?
I built them myself:
How often will the solid lifters need attention?
I've only adjusted them once so far!
How do they sound compared to the hydraulic sewing machines the rest of us are driving?
About the same as the hydraulic lifters in my mind!
Are you going to try running some e85 in the future?
I would if they had it easily available locally but they don't!
Awesome results! Do you run a vacuum pump on the engine? Just curious.
You plan on putting a good tire on it and clocking off some 9 second passes? With a little less weight, a well set up suspension, a good tire, and maybe a 100 shot, you could have an 8 second capable car.
Surprised it hasn't been asked why the mph and dyno numbers don't quite "align"..... Have seen cars with 70-80hp less (and yes, same weight) at the tire run similar numbers.
Everybody certainly likes a dyno number, buuuuuut......
So what did it take….I switched out my Greg Good cylinder heads to a very special set of hand crafted GM LSX cylinder heads ported by Darin Morgan that he made for the Engine Masters Competition but never entered them in a competition. These are likely the best flowing GM LSX LS7 heads on the planet as well….here are the numbers from Rehr Morrison’s flowbench:
This part of the post put a REALLY big smile on my face, as I have been there and know what it takes. Darin's work and RH is no joke.
I'm seriously setting your LS7 as the benchmark for building mine. I'm switching my pistons out for forged ones though, but keeping the Ti rods. I keep staring at them sitting in my living room!
I believe i have the cam that came from the Engine masters motor those heads came off of. There is SERIOUS man hours in those heads. Nice results. Sounds very smooth too.
11-29-2014, 07:11 PM
680RWHP LS7 MCSS now the most powerful NA stock shortblock LS7 @ 700+RWHP! 
