[MightyMach]

Upon my thinking today, I realized that the STOCK BOSS 351 runs faster than my 351 C 4v. Why? Same basic car, (mine is a 73) yet my motor I would have thought is a whole hell of a lot meaner than the BOSS 351.

Remember the build....

351 C .03 over
750 VS Holley
Torker Intake
flat tops
cam is a solid 246 256 Duration @ .050 .564"I .589"E Solid cam
4v Quench heads
hooker super comps 1 7/8" primaries 3" collectors
3" exhaust 2 chamber FM
4.11's
C6 with Shift Kit
TCI Street Fighter stall
Electronic Ignition (MSD everything) timing is at 37*

what is the deal? I am out doing the BOSS 351 in every aspect (minus the Trans) but still, my C6 is built to shift HARD, and FAST. I also have the PS hooked up when I ran the 13.98 @ 102 What is the deal guys!?!?

Thanks a lot!

Jeff Given

_________________

Jeff Given
Sacramento State, Home Town Corona, CA



<font size=-1>[ This Message was edited by: MightyMach on 3/13/02 3:25am ]</font>

 

[MightyMach]

Reason I addressed it to you morgan is because you recomended the cam. I am BY NO MEANS pointing the finger at you!!!!! But I thought we were expecting 12's out of this thing? That was with shitty tires too...and worn out leaf springs with shitty air shocks.

Still the BOSS 351 had the same basic things..yet managed to be 13.8 @ 104 (*pulled off the net just now*)

Thanks a lot!

Jeff Given

 

[Stanley Superior]

Well, for one thing, the Boss 351 was a 4speed stick (that means unlimited "stall speed" if you think about it) and does not require the same amount of power to turn the driveline as the big C6 does.
Also, it has a dual plane intake on it (stock) that helps build low speed torque...something a 4V headed motor is seriously lacking!
Remember, too, that those old car tests were done with some magazine "tricks" to help in the 1/4 mile times.
But fear not! your car sounds pretty stout as it is.

 

[MonsterMach]

Jeff ... My numbers show BOSS 351 ran 13.80 @ 104.10 ... Not sure what your best was up to now.

Keep in mind also ... Those numbers are from a brand spanking new car in "perfect" condition.

Don't get disheartened ... keep at it ... you'll out do that BOSS.

 

[kid vishus]

The trans plays a big part regardless if yours is built to shift hard. I saw a comparison a few years ago that TCI did of all the factory trans on a dyno. The c6 was the second worse power robbing auto, second only to a torqflight. The c6 took somewhere around 60 hp to drive it, that means you are losing 60 hp before it ever gets to the rear wheels where as a stick might take 15 hp. That alone is worth more than a tenth.

A c4 takes around 28 hp to drive. (A GN powerglide took around 14 )

The c6 figure might not be completely accurate, I think it was actually like 62 hp.

<font size=-1>[ This Message was edited by: kid vishus on 3/13/02 4:55am ]</font>

 

[MonsterMach]

Yeap ... I think Kid is on to something there as well ....

Also, with the old Boss and the 4 speed.

We all pretty much recognize that an automatic will be consistently faster than a 4 speed ... However, not necessarily the fastest.

I have to believe that a 4 speed in the hands of a great driver will be darn hard to beat...

Especially when you consider that the 4 speed cannibalizes so much less power.

Point is ... On those "Motor Trend" test runs ... I bet they had a damn good driver behind the wheel

 

[aaron]

with my basically stock boss 351 i have managed a best run of 13.8 @ 105 and that was with a 2.17 60' so those numbers are not inflated unless i got a magaizne car

 

[Hemikiller]

Not only is the C6 costing you, but a Vacuum Secondry holley on a 351C? with a cam like that? C'mon dude, get an 800 or 850 DP and you'll be doing alot better than your present times.

 

[MightyMach]

Well okay, the 750 VS is not the primary choice, but what was on the BOSS 351? My 60' times are at 2.39 I think.

Jeff Given

 

[1970galaxie]

I believe the Boss 351 used a Ford/Motorcraft
spread bore carb. I don't know the size of it,but it was probably a 750 cfm.

 

[RiverRacer]

Jeff. Don't forget your C/R is not 11.7-1. It is probably closer to an actual 10-1 after factoring leakdown, clearence etc. Don't be disheartened. That figures to be 4% difference in most books by itself. Use an 800 DP Holley and it should run 103. Get some cold air and gas into it and it will be at 104. P.S. Tnx for the 10.00 in the mail.

 

[MightyMach]

River Racer....10 $ in the Mail??

Jeff Given

 

[Mach1Morgan]

On 2002-03-13 02:04, MightyMach wrote:
My 60' times are at 2.39 I think.

Your 60 ft time tells me that's most of your problem. Is it spinning or bogging? What's your stall speed? Did you ever find out what your rear gear ratio was? What is your RPM and what gear are you in at the top end? What RPM are you shifting at? How high does the engine want to pull hard to? A 2.39 time in 60 ft is very slow. As a reference, a good running 5.0 with street radials that hook decent can run that et with only a 96 to 98 MPH trap speed and a 2.05 - 2.1 short time. My mild 351 will run 13.70's with only a 96 MPH trap speed with slicks and has an average 60ft time of 1.80-1.85. You've got almost a 1 second et reduction waiting for you if you can just get your 60ft time to where it should be. Every combo needs a bit of time to get the tuning sorted out. My first run with the Windsor was a less than spectacular [email protected] 97 MPH with a 2.15 short time. With jetting, jet extentions, driving practice, and tuning, I was able to run as quick as 13.62 and I have at least a 100 HP less than you do.

 

[MightyMach]

On 2002-03-16 19:48, Mach1Morgan wrote:

On 2002-03-13 02:04, MightyMach wrote:
My 60' times are at 2.39 I think.

Your 60 ft time tells me that's most of your problem. Is it spinning or bogging? What's your stall speed? Did you ever find out what your rear gear ratio was? What is your RPM and what gear are you in at the top end? What RPM are you shifting at? How high does the engine want to pull hard to? A 2.39 time in 60 ft is very slow. As a reference, a good running 5.0 with street radials that hook decent can run that et with only a 96 to 98 MPH trap speed and a 2.05 - 2.1 short time. My mild 351 will run 13.70's with only a 96 MPH trap speed with slicks and has an average 60ft time of 1.80-1.85. You've got almost a 1 second et reduction waiting for you if you can just get your 60ft time to where it should be. Every combo needs a bit of time to get the tuning sorted out. My first run with the Windsor was a less than spectacular [email protected] 97 MPH with a 2.15 short time. With jetting, jet extentions, driving practice, and tuning, I was able to run as quick as 13.62 and I have at least a 100 HP less than you do.

Morgan, thanks for the response! I have been checking atleast once a daay to see your response--Minimum!
At start, it is spinning, however, my dad thought it was bogging, and spinning. The rear gear ratio is now 4.11's. (the car was running hihgh 14 seconds with the 3.25 open rear). The stall is a Street Fighter from TCI. The advertised stall is (from summit) 3,000-3,500 RPMs. I am not sure at all what RPM I am at at the finish, but I am into third. I was shifting at 6400-6500 (rev limiter chip is 6500). I think that the motor would pull hard till it blew up to ttell you the truth, but I have not pushed it that hard (cast pistons

) What do I need to get the 60' down to? what is a logical goal, and when I get it there what do you think it will shave off?

Thank you!

Jeff Given

 

[Mach1Morgan]

Sorry for not replying right away. I usually am on the "techboard" and seldom check in "the garage". 4V Clevelands aren't known for having huge loads of low end torque but still, it should be possible with your combo to get your 60' times into the 1.90's. As a ballpark figure, from what I've experienced, the quarter mile times will usually drop roughly twice as much as the 60' times are reduced. You should physically check your stall speed so you know for sure it's high enough. By using the emergency brake and standing hard on the brakes while using 2nd gear on clean dry pavement to torque stall the engine, you should be able to stop the tires from spinning and get a true stall RPM off your tach. Just don't stand on the throttle for more than about 5 seconds as the transmission fluid heats up at an enormous rate when doing that. Finding out what your true stall speed is will help diagnos what you might do to help your car leave faster.

 

[MGT351]

Just out of curiousity what does that 73 Mach 1 weigh??

_________________
87 Mustang GT 5spd 2.73 daily driver
70 Torino GT 429 C6 3.89
70 F100 360 C6 3.25L (in lots of pieces)

<font size=-1>[ This Message was edited by: MGT351 on 3/22/02 10:42am ]</font>

 

[MightyMach]

with me, no gas, headers, alum. intake...3680. this is running on FUMES!

Jeff Given

 

[Silverliner]

Where do race the car? Altitude can play a big role too. I think I live not too far from you, Orange County CA. I've also almost got my '71 back together. It'd be fun to go to the track with another FM dude and see how they run.