I have been running a Summit 650 cfm vacuum sec. that was suppose to be a perfect match for my Summit stage II dual plane intake. It has been on my Grabber for 2 1/2 years and has always had a slight hesitation. Well, it was just replaced with a Holley 770 "street avenger" double pumper(that I got for free...sort of:bananaman) and what a difference it makes. I thought 770 was going to be too much carb, but it seems to respond well. Anybody else running the street avenger? What carb are you running?
Carb ? No. I'm running three Holley 250 cfm 2 bbl carbs on mine. Your Summit carb likely only needed to be tuned for the motor and judging from your description, only the accellerator pump linkage needed to be adjusted. The 770 would only be "too big" if it opened the secondaries up, too far and too soon, depending on the motor its feeding (you left that part out)
Running a 850dp that was flow'd and tuned by The Carb Shop. With minor jetting it did pull 640HP which ain't too bad..................Oh yes, the carb is over 10 years old.
Edlebrock 600cfm but it always ran lean on my old engine. Swapped it out for a 600 cfm Holley double pumper, and still ran lean, even after tuning the crap out of it. So I swapped in a 750 holley street hp and now it runs a little rich. But it RUNS GOOD! Just idles rich. The 308 really likes it at 6500-7000 rpms.
I agree that it needed some tuning, but it has been like pulling teeth to get my "mechanic" friend(who actually built the engine) to get it dialed in. He decided to just replace the carb so I'm not going to complain. I think it is definitely better than what I had before. I had to find a previous thread so I could copy and paste the info. Here are my engine specs.: 302 cubic inch engine bore 0.030 over New cam bearings and galley plugs Brass freeze plugs Crank ground .010 - .010 Clevite 77 bearings Keith Black hypereutectic pistons Sealed power, single moly ring set Lunati bracket master II cam and lifters - 284 degree duration .488 lift advanced 4 degrees CompCams dbl roller timing set Edelbrock valve springs Stock rockers Stock heads(valve jobbed and exhausts ported) Summit stage II dual plane intake Summit 650 CFM vacuum sec. carburetor(now Holley 770 dp "street avenger") Melling hi-volume oil pump Pertronix electronic ignition MSD blaster coil Ford Cobra valve covers Accel wires Hedman headers Magna Flow exhaust C-4 trans with big Billet servo and blue bands Hughes 2800 stall converter TransGo stage II shift kit B&M megashifter Stock Ford 8" rear end and gears
Learn to tune it yourself and give your mechanic friend the boot. It's not rocket science, it's not complicated, all it takes is a little time to learn the basics.
