THREE WEEKS AGO THE BARRACUDA WOULD ONLY GO 1380'S AT 99MPH. I CHANGED MY TIMING TO 11 IDLE, 31 ALL IN.I PULLED THE DOUBLE LIFE POINTS DIST. AND CHANGED IT TO ELECTRONIC FROM A 360. I SWAPPED THE ACCEL TO A MALLORY COIL. I ADDED A GIANT CAPACITOR TO THE DC ON THE MSD6, AND I CHANGED MY SHIFT POINTS UP TO 6,200. I KNOW I DIDN'T NEED TO DO ALL, OR AT LEAST ALL AT ONCE. THE RESULT WAS A 1.4 SECOND IMPROVEMENT TO 12.40 @107. THE LAST OF YOUR GOOD ADVICE IS TO CHANGE MY HOLLEY 850 TO A HOLLEY 750. QUESTION, WILL ANY GOOD 750 DP WITH MECH SECONDARY'S BE OK? OR DO I NEED TO BUY AN EXPENSIVE BG OR PROFORM?. MY FUNDS ARE ABOUT INTO THE MINUS!THANK ALL OF YOU FOR YOUR GREAT ADVICE. MARK. ps ANYBODY HAVE A GOOD 750 REALLY INEXPENSIVE? AND WHATS THE DIFF BETWEEN 4150, 4779,47761? THANKS MARK
Wow, that is an awesome improvement in ET and MPH, you should be proud. OK, for a street/strip drag car there is only one carb to have. It is a 4150 HP/DP, that is 4150 high performance/double pumper. If you have access to a 4150 750 DP you can order the Holley Nascar HP main body from summit and install it yourself for $135.00 plus shipping. Do not get the pro-form unit, the holley unit is worth a full tenth of a second quicker for a mear $10.00. The kit comes with the nascar main body, 72 jets front, 84 jets rear. If you are running any kind of carb spacer make the rear jets 85. You must use .050cc accel. with brown 50cc accel. pump cams front and rear. Also, .045 thousands dog leg accelerator pump shooters are a must. 4 corner idle is also a must, I purchased a pr. of 4 corner trick fuel billet blocks from summit, for approx $105.00. Good idea to get some rear fuel jet extensions since this thing is gonna leave hard. Besides the carb your gonna likely need a little more fuel as well. So go get yourself a carter race 105 gal. electric fuel pump with built in reg. and mount up a good 1/2 inch fuel line and filter to feed that new carb. 4779 is the designated number for 750 holley carbs. My motto has always been the most for the least, this combination works on all motors up to 540HP. Get ready to yank the front wheels my friend. Good luck..
THANK YOU DR. I FOUND A VERY CLEAN HOLLY 750 ON EBAY. ITS IS A 750 DP. MECH SECONDARYS,4 CORNER IDLE. #4779-6. I HAVE 50CC PUMPERS ON THE 850 THAT I WILL SWITCH IF THEY ARE 30'S. IT HAS A CHOKE. SHOULD I MILL IT OFF AND BLEND THE EDGES OR GET THE NASCAR BODY?. IT HAS A 6.5 P VALVE. I ONLY HOLD 3VACUUM IN NEUTRAL AND 2.5 IN LOW AT IDLE. I WILL CHANGE IT TO A 4 0R 4.5. THE STOCK JETS ARE 71F AND 80R.I WILL NEED TO RUN THIS MAIN BODY UNTIL NOV.5. SOOO, UNTIL I CAN GET THE NASCAR BODY, SHOULD I UP THE JETS AS A STARTING POINT?ps i value your opinion and expertise. thank you for sharing your knowledge. mark.
don't bother milling the choke off, definitely plan on getting the Holley Nascar main body as soon as you can, until then go with 71 fronts and 82 rears/83's if using a spacer with a 4.5" power valve. don't forget all the other important details mentioned. Just did one of these up for a friend and he was amazed at the improvement in his B body 440. Good luck Doc..
THANKS DOC. I WILL UPDATE AFTER THE NOV. 4TH RACE. MARK