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If you were building a car from scratch
https://slantsix.org/forum/viewtopic.php?t=37125		 Page 2 of 3
Author:  Shaker223 [ Sun Oct 04, 2009 4:14 pm ]
Post subject: 
You might be hard pressed to find 28.5" tall 14" tires.
Author:  Dave95693 [ Mon Oct 05, 2009 9:32 am ]
Post subject: 
Don't want to go Nitrous at this point. I'm shooting for low 14's being naturally aspirated. At some point in time I may go the Supercharger route but that will be a couple of years down the road. Goal now is to build a good and solid low 14 second car that is reliable and consistant.

Ron Parker, I believe someone has already bought Norms car. Besides, I like turning wrenches (46 years now) and get areal kick out of starting up a new project. Albeit this is my first true racing project, I've built everything from a Triumph Spitfire to a Fiat X-19 to a 73 Roadrunner, my current car a 71 Demon and now the 66 Dart. What fasinates me is the amount of knowledge required and I am always learning something new (as I'm sure you do). For me this year it's been transmissions and rearends. It's really cool to have a place like this to discuss issues. I guess it's time to make a donation!
Author:  Dave95693 [ Wed Oct 21, 2009 3:08 pm ]
Post subject:  Wow.
I did a Wednesday night race at Sacramento with the new 3:91 gears in my 71 Demon. Stock motor, 2bbl, 2.25 exhaust and 28.5 in 14 in tires. Man, what a difference. The stock motor is hitting 7k rpm at the finish line. Question: When you build these cars, when do you want to reach your max rpm and speed????
Author:  Joshie225 [ Wed Oct 21, 2009 3:24 pm ]
Post subject: 
I have a hard time believing 7k RPM. You usually will see parts of a connecting rod or drop valves before hitting 7k. Also you'd have to be running 139 MPH with a 26" tall tire to turn 7k RPM with no slippage. 10% slip is still 125 MPH. Sure your tach isn't set for a 4 cylinder? That would be a much more realistic 4666 RPM. What 28.5" tall 14" tire do you have anyhow?

Some people shoot for max power RPM at the finish line, others like to reach peak power a little sooner. For a car that sees a lot of street duty I run whatever gear I can stand on the freeway and eat the small ET penalty.
Author:  madmax/6 [ Wed Oct 21, 2009 8:19 pm ]
Post subject: 
Sorry butt I agree,no way you were at 7000,with that combo ,it isnt possible.My car with 26 tires and 4.56 gears goes tru the traps all in at 6200.104 mph.Think your tach is lying.Guzzi Mark
Author:  Dart270 [ Thu Oct 22, 2009 5:00 am ]
Post subject: 
I know a guy who had his tach on the 8cyl setting. He blew at least 2 motors before he figured out he was spinning 6600 instead of 5000. :oops:

Lou
Author:  Dave95693 [ Thu Oct 22, 2009 8:05 am ]
Post subject: 
Seemed like a little much to me too. Thus my question. I don't have electronic ignition, so the tack is counting impulses directly from the distributor. I've never compared it to another tack....but obviously the time has come. I don't think there is a setting on the tack but I'll check it out tonight.
Author:  Joshie225 [ Thu Oct 22, 2009 8:36 am ]
Post subject: 
The tach, if it's modern, can have DIP switches, a rotary switch or even a wire loop or two to cut for selection of the number of cylinders. What brand and model tachometer do you have?
Author:  Dave95693 [ Thu Oct 22, 2009 10:16 am ]
Post subject: 
Not sure what brand it is. Will have to check tonight.
Author:  Doc [ Thu Oct 22, 2009 10:38 am ]
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The biggest problem I have with the 63-66 Darts / Valiants is the low rear quarter panel line and lack of rear wheel well space.
Those A-body cars really limit the size of tire you can use unless you move everything in-board.
DD
Author:  Rick Covalt [ Thu Oct 22, 2009 5:26 pm ]
Post subject:  14's are easy
If 14's are your goal, in a light weight car like a 63-66 A-body, it should not be that hard. As others have said. Headwork, camshaft and gearing are going to be your most important items. Get them right and you may skip right over 14's in a light weight A-Body.

My sons 72 Swinger runs 14.80's and is a all steel, nothing removed to lighten it, street car that weighed 3170 at Mason Dixon back in May. You probably will be under 2800# with a "race" car. That would put you at low 14's with his set-up.

Just as a reference, as Doc mentioned, there is not a lot of room in the rear for big tires. I have my wheel wells removed, and moved the springs into the frame rails on my 65 Valiant.
I just measured the distance from the frame to the quarter panel and I think I measured 13 1/2". That is plenty of room for tires if you get them well centered in that space.

Good Luck,
Rick
Author:  Dave95693 [ Tue Oct 27, 2009 10:15 am ]
Post subject: 
After racing this last weekend at Redding, with the new 3.91 rear end I decided that I really like that gear ratio. My thinking is with a cam set at 284 degrees with .495 intake and .505 exhaust will be sufficient. The only question in my mind now is the torque converter. The numbers tell me a 3200-3800 stall with the new setup. Do you guys concur? One other thing. I've been told that dual exhaust gets you nothing due to weight concerns. With the headers it would be real easy to take the pipes out to just in front of the rear wheels for an out turn.
Author:  Doc [ Tue Oct 27, 2009 11:14 am ]
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Race cars do not need exhaust pipes... :twisted: :shock:
DD
Author:  Dart270 [ Tue Oct 27, 2009 12:56 pm ]
Post subject: 
3200-3800 sounds like the right range for stall - do it. Dual exhaust is for looks only, except on those V engines.

Lou
Author:  Dave95693 [ Tue Oct 27, 2009 1:14 pm ]
Post subject: 
Sounds good.

Doc, pm me your address so I can send you a check for the distributor.

Thanks all! :D
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