10 mpg Speed demon

[el-camino]

hi
i run on my elcamino with a 750 VE speed demon.
the car runs great, dyno 330rwhp.
when i read in many forums about consumption, i don´t understand my engine. 10 miles per gallon, i think this is heavy.
the barry grant speed demon have the stock setup:

MODEL #

750V

PART #

1402010VE

VENTURI SIZE:

1.400

IDLE AIR BLEEDS:

.070

H.S. AIR BLEEDS:

.039

BOOSTER TYPE:

DOWN LEG

BOOSTER LEG:

.160

SQUIRTER SIZE:

31 STD.

BUTTERFLY SIZE:

1-11/16

AIR HOLE SIZE:

NONE

PUMP CAM #

# 330

PUMP CAM COLOR:

PINK

VACUUM SEC. SPRING:N/AYELLOWPLAINPLAINPLAINMETERING BLOCK # P.

A-12400

METERING BLOCK # S.

A-12402

SIPHON BREAK:

.028

E-HOLE POS. #1

.031

E-HOLE POS. #2

N/A

E-HOLE POS. #3

.031

E-HOLE POS. #4

N/A

E-HOLE POS. #5

.031

P.V.C.R. SIZE:

.059

TRANSFER SLOT RES:

OPEN

IDLE FEED RESTRICTOR

.033

MAIN JETS PRI:

# 76

MAIN JETS SEC:

# 83

POWER VALVE PRI:

6.5 STD.

POWER VALVE SEC:

N/A

LINKAGE TYPE:

VACUUM

N&S SIZE/TYPE:

.110-VITON

ACC. PUMP DIA. SIZE

30CC

any idea what i can change or set up ?