I enjoy watching the progress of these cars. Keep at it! I am sure it is frustrating to not hit the mark on the first few trips to the track. I know I would be discouraged at the prospect and expense of trying to locate the missing .5-.9 seconds from a working combo.

That said, I don't think its right to imply Dave has held back any secrets to his combo, or snookered anybody regarding his engine specs. He has posted the specs all over the internet many times. He certainly spoke freely about the details about this combo in every regard when I spoke with him on the phone a few years ago. He disclosed the full specs of the motor when he had it for sale, also.


Is the cam exactly right for a 3400+lb car? Probably not what the current trends suggest. Seems like intake duration trend is around the 230° range for the rectangle heads on 6.0-6.2l these days.

Fast89Stang is close to Dave's times and is running less cam. .622/.600, 231/243 111+3
Martin has posted up some smaller cams for rectangle stuff now, also 229/248 109+3

.624/.624 239/247 110+4 is a pretty large cam for a dual purpose rectangle port 6.0L. That cam is probably larger than most would run with rectangle ports and low (10'ish) compression. It needs and requires a significant amount of stall and gear and carb to come to life. Take away any one of those essential elements and ET/MPH will suffer (is suffering) accordingly. 500lbs additional weight makes nailing the converter specs that much more important.

As an aside, Dave Mizell's complete powertrain (6.0L Engine/8" ATI/UltimateConverter/TH350Trans) now resides in a cool 1957 Corvette and it still pulls 9's through the mufflers at nearly the same 2900-2950'ish raceweight as the mustang.

 

If either one of our cars had enough converter slippage, or shift extension, that it sounded like a motor boat going down the track, than I would agree with your mph theory. But that's not the case.

But I do agree with you that the converter is PART of the problem here. Just not THAT big a part. Eric L

 

I agree that the combination of stall, gear, and carb is essential to this combo........but heres the points your missing.

Dave ran 130+ mph with a 3.73 gear (before the 4.10s)
Dave ran 130+ mph with a 3800 converter (WAY to tight)
Dave ran 130+ mph on a foot brake
Dave ran 130+ mph with a 1.55 60 ft

Dave ran 130+ mph reguardless. Because he was putting down the HP to do it. Don't get me wrong, I believe that its in their, I just need to find it. And I will. I believe my first course of action is going to be borrowing a bigger carb and letting it eat. lol. Eric L

 

Lets not forget he said untouched heads...mine are cut .050 (so about 10.5:1)
IF it's the converter that's that bad....it would be a huge surprise.
Shift extension is 1000-1500 depending on my shift points.
NOT calling Dave a BS'er...but VERY odd that 2 "copies" didn't perform anywhere near his but nearly identical to each other

Yes, we both have things that aren't 100% to his and not optimum for the desired outcome...but to the tune of 1.0 seconds

 

That sounds like it has only just enough converter and is probably still dropping slightly out of maintaining peak AVERAGE horsepower. I rest my case.

Imagine how lazy a similar stall speed would be in a heavier car!

 

Dave ran 130+ mph with a 3.73 gear - Not so critical with right converter.

Dave ran 130+ mph with a 3800 converter - Foot brake speed not the be all and end all when already very close to having the right converter.

Dave ran 130+ mph on a foot brake - Easy done when maintaining average HP with the right converter.

Dave ran 130+ mph with a 1.55 60 ft - Getting out of the hole has little to do with trap speed. Shift extension and efficiency that will maintain average hp is what it is all about with the right converter.

 

That is terribly inconsistent and never going to deliver solid results. Not to mention I have read nothing good when searching for info on Art Carr converters online.

 

When I changed from a 3000 stall to a 4000 stall my car picked up ET and consistency, the ultimate MPH remained the same.

3000 converter:
60’ - 1.64 to 1.69
Best ET - 11.27
Best MPH - 120
Shift Extension approximately 1800 RPM

4000 Converter
60' - 1.52 to 1.54
Best ET - 11.05
Best MPH 120
Shift extension approximatelu 1000 RPM

The difference between the two was ALL in by the 330' mark. However, the ET and MPH are notably more consistent.

 

Isn't the internet great. I spent part of last night discussing automotive theories, sitting on my couch, in my underware, eating Doritos, with people I never met, from all over the globe.

I think a good time was had by all. Eric L

 

Lol
......

 

That is a visual I did not need. LOL

 

Hey Eric.... just make sure the flap stays closed

Steve....ET went down due to better 60'

As for the Vette...a proven combo (motor and trans) moved into a sorted chassis, at very near the same weight....What would you expect ?

V....so what converter would you recommend ?

 

Yep, but I guess I forgot to make the rest of my point. That demonstrates what you get going from a tight, efficient converter, to a looser efficient converter. The other end of the deal is when you have a loose or damaged converter with poor efficiency for the combo, it is MPH that you lose.

Here is a story I shared with Eric:

Way back in the day, one of the guys at the track pulled the 8 second big block and converter out of his dragster and put it in hos son's 57 Chevy. We were all lined up around the starting line to see what this shoe box was going to do. It would not go any faster than 13s! It sounded like he was on the trans brake all the way down the track. They changed the cam and converter and it went over 2 seconds faster first trip out. That is an extreme example, but, I thought is was worth sharing.

 

Talk to several reputable converter builders with an extensive track record. If you think an 8" converter is the same as the next 8" converter you have virtually zero knowledge on what is the most important part in any car.

Look at all the emphasis guys on here and everywhere put on camshaft design, now consider the converter is much more important to get right.

 

VLS1 is 100% right here guys.

You're missing the big picture.

 

Looking at getting converter tightened up and re-stalled. Found the builder of my converter....now going to get it built for THIS combo.
Still hard to believe it's a full second....but know it's worth a few tenths. We shall see.

 

If it didn't pick up mph, yet shift extension was "improved" that much sounds like it still isn't super efficient. The shift extension may be there but could well be slipping more in the upper RPM band overall.

 

And who built it anyway?

 

I was not surprised that it did not pick up MPH. It pretty much did exactly what I expected.

There are a couple things at play though. I have a small, midrange power cam and I have 3.90 gears and a 28" tall tire. If I had some 4.30 gears and a cam that really needed that narrow shift extension, it probably would have picked up MPH. But, with me running a 200 shot, I can't make the 1/4 with shorter gears.

 

Art Carr.... but I found the guy who did the converters for him. Has his own shop now since AC went Out of Business.