Mike C Posted January 23, 2003 Share Posted January 23, 2003 This is a transgression of sorts, specifically back to Pete P looking for advice on carb. My thoughts have always leaned towards big double pumpers (not Dominators, however) and this tests results mostly confirm my observations. This is the summary from the April (April!? Already!?) 2003 Super Chevy where they dyno tested, including optimizing the fuel curve, 12 different Holley carbs. So, if you are on the fence for a carb, or you are just an info junkie like me, maybe this will help. 750 0-4779-8 390 0-8007 570 0-80570 600 0-1850-6 650 0-4777-7 670 0-80670 750 0-3310-5 hp750 0-80528-1 800 0-4780-6 830 0-9381 the only annular boosted carb 850 0-4781-8 hp950 0-80496-1 -Only 3 (850, HP750 and HP950) of the carbs averaged over 400 lb ft, and only the two HP carbs peaked over 430 hp (the 4779 was close at 399 avg torque and 429 hp-best bang for the $ IMO and probably within the dynos margin of error could have been over.) -The HP950 made more torque at 2500 rpm than any other carb with the 650dp right behind it. -The 650 and 750 dp carbs tied for most torque and hp at 3500 rpm. -The 750 vac had the lowest mid-range figures of any carb -Peak torque occurred between 4100 and 4300 rpm and peak hp between 5400 and 5700 rpm with EVERY carb. -Average power tells the whole story, and the two hp carbs made more average power than any other carb. (As noted above, however, the 750 dp was CLOSE and it has a choke for street driving.) Please forgive my parenthetic insertions p.62 of the mag has the complete dyno chart for every carb. Quote Link to comment Share on other sites More sharing options...
z ya Posted January 30, 2003 Share Posted January 30, 2003 Thanks for the info. I have a 650 DP and a 750 vac sec(3310) for my 350. I just got the 650dp and can wait to see how it feels. Throttle response seems MUCH better. Quote Link to comment Share on other sites More sharing options...
Guest Phil1934 Posted January 30, 2003 Share Posted January 30, 2003 Being thrifty, I've always considered Holley to only have two choices, the 3310 or the 1850. How did these two stack up? If they are near the bottom I may have to loosen the purse strings nest time. Quote Link to comment Share on other sites More sharing options...
Mike C Posted January 30, 2003 Author Share Posted January 30, 2003 As noted above, the 750 vac, the 3310, had the WORST midrange torque figures and average topend output. The 1850 is just too small for a performance application IMO. IME, the BEST Holley is the 4779 double pumper. To pat myself on the back, tests bore this out as it was the only non-HP carb to come close to the 430hp peak and 400#/ft average torque numbers. It also lets you run a choke for a street car, which is a real plus if you ever drive in cold/cool weather. I have a Barry Grant modified 4779, the stage III. It flows a peak of 1040cfm but has throttle characteristics of a 750 because they keep the stock venturi and throttle blade size. It has had the choke horn machined off, the venturis polished, downleg boosters, modified air bleeds, and reduced profile throttle shafts installed. They also plug all the exra vacuum fittings which is kind of a hassle. It was stupid expensive at the time (1994 cost was $625, but that seems to be middle-of-the-road now for max output carbs.) This is pre-Demon stuff, as the Demons don't seem to work as well as they Holleys from what I can tell. My S3 runs great, but if I had it to do over again, I'd run the box-stock 4779, or for a MAX effort car (500+ hp) then one of the HP carbs with replaceable airbleeds. Carbs seem to follow the traditional Hot Rodders adage: "You get what you pay for." Quote Link to comment Share on other sites More sharing options...
John Scott Posted February 23, 2003 Share Posted February 23, 2003 Mike what are the engine specs, comp ratio, cid, cam, heads etc, for the Super Chev engine? The 750dp seems like a great deal and within a few hp of the mighty hp series. Anyone want a shiny Road Demon for cheap? John Quote Link to comment Share on other sites More sharing options...
Mike C Posted February 23, 2003 Author Share Posted February 23, 2003 The motor is one they call Danger Mouse. It is 355 ci and has been subjected to over 275 full throttle dyno pulls in various combinations. It has an expensive rotating assembly because of its expected usage. Different heads, cams, intakes, rocker ratios, etc. have all been tried, and this is the combo for the carb test: 355ci 9.25:1 compression GMPP Vortec heads COMP XE268H cam Airgap RPM intake 1" spacer 1.5 Magnum roller tip rockers This is my best guess as they didn't say exactly for the carb tests. With this combo they quote 439 max torque and 427 max hp which is close to the carb test numbers. But the carb test was done at a different dyno than the other tests so there may have been a few other minor differences. peak tq/hp 4779-8 429/406 HP750 432/408 HP950 432/409 Here is a link to the web version of the article. It was not up when I first posted this thread. http://www.superchevy-web.com/tech/0304SC_DangerM8/ Quote Link to comment Share on other sites More sharing options...
Guest zfan Posted February 23, 2003 Share Posted February 23, 2003 I read that same article on that build up and can't believe they got those numbers with that set up. Hell I'm going to dyno my Z next saturday and see what I come up with. It will be an interesting comparison. Mine is a 350 four bolt 30 over 10.3 to 1 Comp cams extreme energy Hyd. roller 224/230-500/510 Edelbrock rpm heads 64cc straight plugs 1.5 roller rockers Weiand stealth dual plain intake Holley 750 double pumper Hooker 1 5/8" long tube headers 2 1/2" dual exhaust Msd pro billet/6a box/blaster two coil Taylor spiral 8mm wires I'm guessing 375 horsepower and maybe 400 ft. lbs of torque. Car runs mid 12's and is a 71 240Z so is pretty light. 400 plus ponies would easily give me 11's, probably mid 11's. Mike Quote Link to comment Share on other sites More sharing options...
John Scott Posted February 23, 2003 Share Posted February 23, 2003 This is the second article I've read where the bigger than expected dp carb has produced more av tq and hp. I'm wondering if current theory might be wrong for sizing. In the other test a Demon (sigh) jetted down had way better figures than another smaller Demon cfm carb. John Quote Link to comment Share on other sites More sharing options...
Mike C Posted February 24, 2003 Author Share Posted February 24, 2003 Mike, My 355 runs mid 12's in my Camaro (12.60's), with a CRAPPY 2.0 short time, 110mph trap speed. It weighs 3500# with me in it, so I figure about 365 rwhp. I would think your Z would run 11's? Just guessing that the RWHP #'s come back around 290. Please post as I would like to know. never dynoed my car and except for the carb, it is "as is"I built it in 1988. It would be interesting to strap mine on a dyno. May have to look for a club day around here. Quote Link to comment Share on other sites More sharing options...
Guest zfan Posted February 24, 2003 Share Posted February 24, 2003 Mike, Yah I could not pass up the dyno day offer at the Horsepower store next saturday. 3 pulls for 30 bucks Will get horsepower, torque and fuel reading. My best 60 ft. is 2.08 My transmission was slipping as well, it's a 700r4 with 23/2500 stall. it would slip as I shifted at 6k it would wind to 6600 to 7k before shifting . All that should be behind me now as my friend has a close friend who builds HP trannies for a living and he built me one. I installed it 2 months ago but due to the season I have had no track time as of yet! It does have a mean shift now! Mike Quote Link to comment Share on other sites More sharing options...
z ya Posted February 24, 2003 Share Posted February 24, 2003 Yeah, I cant beleive those #'s on that Danger Mouse. I dynoed mine when I got it done about 6 months ago. I ended up putting down 275 rwhp and 280 rwtq. I was disappointed. The good thing was that the A/F was a horrible 10.0 across the board. The dyno dude told me I had alot more in it once the get the A/F in the 13 to 13.5 range at WOT. This was also with the 750 vac sec Holley 3310. Now I have the 650 DP and also have added a windage tray. I am hoping for 300rwhp once it gets sorted out . Also may install a carb spacer later as well. Quote Link to comment Share on other sites More sharing options...
Guest zfan Posted March 2, 2003 Share Posted March 2, 2003 Well Dyno day came and went, and it sucked royaly! There fuel A/F was down so only got to run horsepower and torque numbers. My car was running extremely rich, Guy running dyno said to lean the jets 2-4 sizes Black smoked out the place. Numbers for my build were shitty to say the least! Three runs as follows: 1. hp-261.3 Tq-269.1 2. hp-269.1 Tq-274.4 3. hp-269.4 Tq-276.4 Max torque was made at 3500 Max horsepower was made at 6000. I can't believe what a pathetic showing this car made. Sounded awsome but... Mike Quote Link to comment Share on other sites More sharing options...
Mike C Posted March 4, 2003 Author Share Posted March 4, 2003 Don't let it get you down. I saw the tuning you were doing in the Chevy board. You may want to think about diggin into the motor again, however. Get the Proform degree wheel and make SURE you cam is where you want it. Then go to town on the distributor and the carb. 36 degrees total by 2800 should be fine for your new design heads. Quote Link to comment Share on other sites More sharing options...
Michael Posted September 19, 2006 Share Posted September 19, 2006 Browsing through the collected wisdom on selection of Holley carburetors, I came across this thread. The article in SuperChevy is still available, here: http://www.superchevy.com/tech/0304SC_small_block_chevy_motor/index.html . However, the web site does NOT list the dyno data itself - only lots of pictures and a few general observations. Does anyone have the torque curves themselves? Quote Link to comment Share on other sites More sharing options...
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