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Outside of this conversation, I never cease to be amazed at hotrodders who fret over every last atom of HP and torque from the motor, but ignore mass almost as if it didn't count. For them, Newton's second law would read F ~ a*m^0.001 (Yes, that's a mathematical joke.) For the OEMs, however, not only do they sweat the atoms, but the grams of excess mass as well.

But it's not just 0-60 or 1/4-mile times. Mass hurts handling too. It has to do with how tires don't obey the Coulombic laws of friction (I go into detail about this in the block-buster Front sway bar project thread.) That's why lighter cars tend to yield better times on the course.

I wouldn't be surprised if the vendor didn't know the weight of the bare frame. And even if they did, it wouldn't be meaningful unless you could compare it to the OE frame in the same trim (250 lb?? Wild guess only,) and the odds of them knowing that are lower still. IOW, good luck (!)
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Ron, btw, one more thing - and maybe you'll want to answer this in the lounge forum. I only rode once in an F-body (1986 IROC-Z,) so I know almost nothing about them. Care to comment on their ride and handling, NVH, and anything else you'd think would be noteworthy? MCSSs nowadays are crazy expensive, but F-bodies are relatively cheap. Thx.

Last edited by MAP; 09/05/22 11:25 PM.
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One thing I noted was the front sway bar, looks so familiar to Bob's. laugh Or I should say Bob's look familiar to this one??

The 1993 - 2002 model F body handles great out of the box in stock form with optional shock and spring upgrades of the day. NVH, NV is awesome, the H a little harsh if you nail a bad northern pothole. The cars are very solid in stock form. With some light mods they're leaps ahead of most anything I have driven. They're torque arm set ups from the factory and accommodate rear exit exhaust.

The weight, for every 100 pounds I add in chassis weight I'll throw and additional 10HP to neutral the gains. I'm sending the heads off the new LS7 to Texas speed to be CNC ported with new longer valve guides installed, and stainless exhaust valves which adds 30hp they say. Eliminating the valve failure issues some read about. I have 300 pounds I can gain plus whatever I lost already from factory cast iron and heavy suspension parts. But honestly this chassis might not be as fat as you think? Depending on the gauge and material composition it can be misleading. These guys are serious designers and I'm certain they have reasons for each action.

Last edited by 1 Slow SS; 09/06/22 12:15 AM.

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Hi Bob,

Thanks for all that. Let's hope I'm wrong about the weight of that frame. Numbers are always nice to have instead of opinions. You have two factors working in your favor: first, the lighter LS-7 compared to the old iron-blocked SBC in the front, and second this frame, which is clearly much more rear-weight biased than the factory frame. Hopefully, you can cut 50 lb of fat from that frame so the lighter motor more or less cancels the additional frame weight.

We know that acceleration maps better to TQ than HP, but both can misleading. Every extra 100 pounds represents about 2.7% of the car's base weight. From experience you'll need more than 2.7% more hp from the motor to compensate: I'd say more like 4-5%. So 500 hp would need to go to roughly 520-525 hp just for the extra 100 lb. Reduced weight pays off big time.

Last edited by MAP; 09/06/22 05:52 AM.
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This engine is 570 hp from GM, the heads bring it to 600.


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I'm guessing the crate motor is tuned quite differently from the factory-installed LS-7. So I had a long talk with Gerry about the tuning of the LS-7 cam: why such a crazy-wide LSA, for example? This came at a time when he and I were debating the merits of a 383 SBC cam David Vizard and I were working on for good economy. The short answer for the LS-7 was good economy, low emissions, and good tranny stability on the low end, and reasonable power at the top. But it came at the cost of midrange torque. My modeling and the testimony of several aftermarket tuners confirmed it's very easy to change the cam for big midrange and HP gains. But as usual, economy and bottom-end grunt take a dive. With ICEs, you can never have it all at the same time. (With electric, you can, but that's another conversation.)

And what is the "all" that ICEs deny? It boils down to high peak HP and a wide engine torque bandwidth. You can have one or the other but never both.

The crate LS-7 might be dynoed to different standards as well. But all the arguments based on percentages still hold.

Last edited by MAP; 09/06/22 08:43 PM.
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Hi Mark,

GM makes a LS7 570 HP engine with an upgraded more egressive cam shaft. This is a wet sump engine verses dry sump also.

Regards
Ron


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Hi Ron,

Thanks - exactly my suspicion.

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With a LS7 it’s a mindless job to belt out upwards of 700hp NA. The engine is a race bread machine that made its way into pedestrian vehicles. I was looking to finish a project quick with some short cuts. Honestly it might be best for me to stop this build thread and just post the car finished. I'm not that interested in all the theory and design work of building a G body. I can build a 200K V code Mopar or a 50K F body and I don't need to run software modeling, those folks over there just like clean cool cars that work. For me this was a project to get away from my work stress and most importantly life's stress. I almost lost my wife this year to covid, she was in the hospital for 48 days and wasn't predicted to survive. This event has given me a reality check on what's important, and cars aren't. They're fun toys to enjoy while we have our health. If it makes you feel good or empowered flaunting education and or theory maybe be a professor, but honestly I think it's all BS! I have a long standing GM engineering heritage in my family and listened to debates over dinner as a child though out my whole life. It all means nothing to me because I can, at the drop of a dime build a car to run with any jack azz out there.

Mark, it's not personal and I apologize if you take it as a jab, which it's not.

https://www.corvetteforum.com/articles/chevrolet-performance-ls427-570/


Last edited by 1 Slow SS; 09/06/22 11:21 PM.

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I was only trying to help. Next time I suggest you do that by PM. (I'm very happy your wife pulled through, Ron, and I'm sure I speak for everyone here too.)

You're reminding me that hot-rodding has evolved from cubic inches to cubic dollars. Maybe I should say cubic hedge funds counting recent inflation.

And of course, as you wish, over and out.

Last edited by MAP; 09/07/22 05:47 AM.
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I hope your thread continues, I don't post much but do keep up with it. A guy close to me in knoxville had Roadster Shop build a frame for a c10 a couple of years ago and I can tell you that the frame and craftsman ship on that frame was A+.

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No, I won't stop the build thread. I shouldn't be that way and send apology to all members. I just get a bit frustrated with things "life" and vent at the wrong folks at the wrong time. Mark is a very smart fella, I respect his angles and knowledge.


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Hi Ron,

Thanks. OK, I'll just say this before (really!) shutting up. First, glad to hear you'll be continuing the thread. I'll continue to watch from the background and root you on. Second, I've got to say again, that I was only trying to help.

So I hope you enjoy this to the full. But if I could submit an encouraging word to someone who is my senior, I would only say that when we think we're too old to be inquisitive and learn, and think we know it all, then we are - too old. Speaking for myself, I've barely scratched the surface. I wish you a happy return to a youthful attitude of inquisitiveness and discovery.

Btw, you've hinted you've made many interesting car builds. It would be great if you shared them in the lounge forum!

Best,
MAP

Last edited by MAP; 09/08/22 08:57 PM.
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I have been in contact with Patrick at the roadster shop, the frame the way I want it rolling is just south of 30K. It will hold a 345 tire out back, Bear brakes and several other upgrades. The chassis is 10 months out for production.

I will have many very nice chassis parts, frame and a near new 12 bolt Moser rear for sale soon.

Last edited by 1 Slow SS; 09/08/22 09:10 PM.

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Might be interested in a few things.

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This build will take another turn. I was going to tub the rear and throw meats on the back and had an alternative thought. I have inquired about stretching the quarters and fenders, not flaring only the wheel well lip but leaving that intact and pulling the whole body panel out on a gradual taper with a 62.500 track width all the way around on a widened chassis. The doors will be recessed similar to a new Camaro. Only live once and what the heck, lets see what we can do here?? Pat should have some budgetary numbers next week, then I can bust the piggy bank open!

BTW, I copied Marks drawing and sent it to the roadster shop. Marks 17 year old drawing will come to life in the next year with a killer factory style custom paint job!

This should emulate the sketch MAP has posted. Mark could you post your drawing below?

Regards,
Ron

Last edited by 1 Slow SS; 09/09/22 10:50 PM.

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Hi Ron,

Here's the thumbnail:

[Linked Image]

The sketch kind of hints that the flaring in the body in front of the front wheel well, up to the joint with the front fascia, isn't straight but curved concavely. It's simple cosmetics but I think it looks much better this way.
Also, Ron, are you going to move the front wheel well forward (and thus stretch the frame) by 4"? I later found that 3" is innocuous but 4" starts to look a little funky.

Also, you'll probably want to go wider with the flares because you're proposing roughly 4.7" more track width than stock. Btw, you'll like the extra space this makes for the engine. Miles of clearance for headers...

You're broaching new territory here, Ron! I think you'll love the results, and you will definitely have one truly unique Monte!


Last edited by MAP; 09/09/22 10:36 PM.
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Originally Posted by MAP
Hi Ron,

Ron, are you going to move the front wheel well forward (and thus stretch the frame) by 4"? I later found that 3" is innocuous but 4" starts to look a little funky.

This won't happen, I can't afford to make the car longer.

Also, you'll probably want to go wider with the flares because you're proposing roughly 4.7" more track width than stock. Btw, you'll like the extra space this makes for the engine. Miles of clearance for headers..

I'm actually going to add 4" of additional track width over factory @ 62.5 if that's correct? I'll know the numbers soon I would say.

You're broaching new territory here, Ron! I think you'll love the results, and you will definitely have one truly unique Monte!

Yes this is exciting too say the least, I'm very motivated as I'm so impressed by the level of skill I've seen on their builds.



Last edited by 1 Slow SS; 09/10/22 01:22 AM.

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Sorry - I should have clarified that when I said moving the front wheels 3" or 4" more forward, it was while keeping the car at its existing length. The idea is to move only the front wheels and the front wheel-well openings that amount forward. Everything else stays put. Here's how 3" more forward would look courtesy of MS paint (from back in the day when it actually did some useful things):
[Linked Image]



Last edited by MAP; 09/10/22 03:58 AM.
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My late friend Greg Weld put a Roadster Shop chassis under this 40 Ford Pickup and he was beyond pleased with it. I've seen cell phone pics of the Speedometer at 140 mph during the Good Guys Road trip taken with one hand on the wheel and one hand on the phone...it's that smooth and predictable. He loved that truck and his daughter has it now and still loves it to this day.

[Linked Image]


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That’s a very nice truck, thanks for posting Lance.

I’m already getting flak from Mark on the cost, but the quality they put out I see as second to none.


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My good friend Chris Jacobs has had an IRS Roadster Shop chassis under his Chevelle for a long time. Was very competitive on course as well until everyone else just got so much faster. Still a great car that he loves to long haul and race in..

[Linked Image]

He's in Chicago and is real close with the guys at RS.


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I can say this about the Roadster Shop frame that I saw at the fall rod run in Pigeon Forge a few years back is that it stood out. All the frames from all the different manufacturers pretty much look the same as each other at all the booths and the Schwartz looks just like the rest after looking at it on their website. Pretty much just a basic fabbed frame, RS frame looked like a piece of art. I'm not speaking on functionality I'm speaking on looks alone the RS frame put the rest to shame all the way down to all the weld beads perfectly placed. All day there were crowds around the RS frame the others just people stopping to take a glance and moving on. On looks alone I would pick the Rs frame all day.

Last edited by 88ssBrent; 09/11/22 08:40 PM.
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Another sweet ride, that paint looks very slick too.

I'm not looking to build an auto cross car, but yet a great driving street car. Honestly the more I think about it I hate to cut the car up at all. I might just leave it a stock wheel base and run 17" N90 wheels? I'll see this week what kind of money were talking?

Regards,
Ron


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While I'm trying to spend Ron's money for him. Lol. Here is the RS 7.0L twin turbo grand national. Over 300 pictures in the build album link.

https://roadstershop.com/galleries/1987-grand-national/

[Linked Image]
[Linked Image]
[Linked Image]

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Those are two great-looking vehicles!

Well, Ron, you're in a good position with your background to take a step back and think through the scope of the project in realistic terms that will be right for you. Now is certainly the right time to do it. I think most folks, including myself quite possibly (!) would get into it halfway and realize we bit off a bunch more than we could chew. Going forward, I know I'm going to tell myself that despite the best forecasting possible for budget, double it, and it will probably be almost enough smile I know you won't make that mistake.

Best,
MAP

Last edited by MAP; 09/11/22 10:03 PM.
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