Chevy Small Block Holley Carb Tests - Superflow

One of the nice extra features of the Street Avenger line are these fuel level sight plugs that make setting the float level a little easier.
One of the nice extra features of the Street Avenger line are these fuel level sight plugs
On carbs with chokes we had to make sure the choke didn't close when we made a power pull. A small vacuum cap wedged in tight did the trick, but don't try this on your daily driver as it might vibrate loose and get sucked into the carb.
On carbs with chokes we had to make sure the choke didn't close when we made a power pull.
Shop owner and dyno operator George Vrbancic personally checked each carb to make sure it was getting full throttle before a test was made.
Shop owner and dyno operator George Vrbancic personally checked each carb to make sure it

Vrbancic Brothers' DTS dyno has been very good to the editors at SUPER CHEVY. Its reliability and repeatability have made testing with it very consistent.
Vrbancic Brothers' DTS dyno has been very good to the editors at SUPER CHEVY. Its reliabil
Both of Holley's HP-series carbs (the 750- and 950-cfm models) made more power than all the other carbs tested. The HP950 even made more peak and average power than any other carb. That's really saying something for the crew at Holley who designed the HP lineup.
Both of Holley's HP-series carbs (the 750- and 950-cfm models) made more power than all th
One other interesting comparison is that the venturi boosters-the things in the middle of each venturi-can change drastically from one carb design to another. On the left is a standard 750 double-pumper with regular down-leg-style boosters. On the right is the only carb we tested (the 830-cfm 0-9381) with annular-style boosters.
One other interesting comparison is that the venturi boosters-the things in the middle of

	670-cfm vs		750-cfm vs		HP750 dp		800-cfm dp		830-cfm dp
	(0-80670)		(0-3310-5)		(0-80528-1)		(0-4780-6)		(0-9381)
RPM	TQ	HP	TQ	HP	TQ	HP	TQ	HP	TQ	HP
2500	344	164	337	160	356	169	343	163	340	162
3000	391	223	386	221	401	229	404	230	402	230
3500	403	269	388	259	416	276	410	274	416	277
4000	417	317	394	300	429*	327*	424*	323	422	321
4500	411	352	396	340	422	362	418	358	420	360
5000	401	381	388	370	414	394	406	387	407	387
5500	373	391	371	389	388	407	379	397	380	398
6000	332	379	331	379	343	392	336	384	341	389

Peak	419	391	400	391	431	408	427	399	427	403
@	4100	5600	4300	5700	4100	5600	4200	5700	4200	5700
Avg	390	315	380	307	403	325	398	321	398	321

	850 dp		HP950 dp
	(0-4781-8)		(0-80496-1)
RPM	TQ	HP	TQ	HP
2500	347	165	353*	168*
3000	406	232	407*	232*
3500	412	274	414	276
4000	427	325	429*	327*
4500	421	361	424*	364*
5000	409	390	415*	395*
5500	384	402	390*	409*
6000	341	389	347*	396*
Peak	429	403	432*	409*
@	4100	5700	4200	5500
Avg	401	323	404*	326*

* = Indicates highest figure recorded
*t = Indicates a tie for highest figure

Some Interesting Dyno Observations
*Only three (850 dp, HP750, and HP950) of the carbs averaged over 400 lb-ft of torque, and only the two HP carbs (750 & 950) peaked over 430 lb-ft of torque.
*The HP950 made more torque at 2,500 rpm (353 lb-ft) than any other carb, but the 650 dp was right behind it with only 1-less lb-ft (352).
*The 650 and 750 dps tied for most tq and hp at 3,500 rpm.
*The 750 vacuum secondary carb (List 0-3310) had the lowest mid-range figures of all carbs.
*Peak torque occurred between 4,100 and 4,300 rpm, and peak hp occurred between 5,400 and 5,700 rpm with every carb.
*Average power tells the story and the two HP carbs (750 and 950) made more average power than any other carb.
*Note: Faithful DM followers may note that peak power numbers for this test were down by a couple percent from previous tests. That discrepancy is most likely just the difference between how a DTS dyno and a Superflow dyno collect and interprets the data. It's kind of like stepping on the scale at your house vs. your friend's house; either scale may be correct, but you'd still weigh the same regardless of the difference in readings.