DeTomaso Mailing List: April 99, Message #93

I know I am late with my response to this thread, but here it is:

My 74L runs a 650 double pumper mechanical secondary Holley.

When I first got the car in 1993 in CA, the plugs would foul fairly quickly.  
I solved that by adjusting the idle mixture screws until I got the fastest 
idle I could, which, if I recall correctly, resulted in the screws ALL THE 
WAY IN.  That does not sound right to me, but the car has run fine since, 
other than rebuild kit for the carb in 1994 to replace leaking gaskets.  (The 
car had not had much driving, as it had about 11,000 miles on when I got it)

I have not touched the carb since 1994.

To me, the car runs good, pretty good throttle response, pulls smoothly.  
Dave "I blow engines for grins" Doddek has ridden in it recently, and I think 
he said the car seems to have the right amount of performance for what it is: 
mostly stock, usual mods.  

What say you, Dave?????  You have far more engine experience than I.

My car also has the Edelbrock Performer intake, full tubular (GTS?) headers, 
some (Allison, I think) aftermarket ignition; and the previous owner's 
mechanic said it had been ported and polished.

The mechanicals seem to work fine on the street, as I have never had any bog; 
though I never suddenly snap the throttle open, and really very rarely exceed 
4,000 RPM.  Torque seems quite good, but this is the only Cleveland-motored 
car I have driven.

I imagine I could do better with more detailed tuning, and I have no idea 
what jets, etc are in it.  But I am too cheap to replace or spend a lot of 
time messing with what runs well.

The car came with (not installed) an electric choke kit for the Holley, but 
the choke flap is wired wide open, and all I gotta do to get a quick cold 
start is pump it a few times (up to six when it is 20 degrees in the garage) 
and crank it.  Thus I have had no incentive to add a choke system.

Gas mileage is lousy, at 8-12 around town and a little better on the highway. 
 The above start drill I am sure does not help.  But nobody buys a Pantera 
for gas economy, right?

This is the only car I have had with mechanical secondaries, and before this 
had not had a four barrel car since 1974 (68 Olds 442); so I do not have a 
good frame of reference to compare.  My 1993 Mitsubishi 3000GT VR4 (sold it 
two years ago) seemed faster than the Pantera to me, but that might have been 
just an impression due to the twin turbo "rush."

Does all the above sound about right for a mechanical-secondary carb set up 
decently for this engine?  Am I lucky, or should I be expecting more? I have 
done three or four autocrosses with the car; just tool around them in second 
gear.  No stumble or falter.

chris bupp/#6588