I intend on doing a TPI swap (already have everything to do it), but since I want to take my time and buy some nice aftermarket pieces for it, I'm going to put my car back on the road for a while with the carb still on it. Right now it has a little holley 600cfm list #1850. Runs perfect, but I know this carb is holding back some horses. My motor goes as follows: 355 with forged flat-tops, 9.5:1 compression Comp Cams Xtreme energy 268H cam (224/230 @ .050 and .477.480 lift) Fully ported and polished (professionally done) 487 casting heads with 2.02/1.60 manley raceflow valves Edelbrock performer intake 3.42:1 gears, TH-350C with 2000 stall converter (got a 2800 stall coming), 1 5/8 full length headers through full dual 2.5" pipes, highflow cats and chambered mufflers A friend of mine has offered to trade me a holley 4010 series carb straight up for a 600 holley that I just rebuilt (it was a spare). He said the 4010 is a 750 cfm double pumper, but he also said its vacume secondary, which makes no sense. If it is a 750 double pumper, would this carb be decent for my engine? I figured a double pumper is a bit overkill, but if it makes good power I'm happy, I expect a bit worse fuel mileage than the 600. Is the 4010 a spreadbore or squarebore? I know the 4011 is spreadbore, but I'm not sure about the 4010. I can't seem to find much info on the web about these carbs. Thanks for any input.

The 4010 is a piece of dung. The reason he wants your cheepie 1850 is because he hates his POS. Those never really run good, they're not at all the same thing as a real Holley. I'd advise against it.

I agree with RB.... Just soup up your 1850.

Change to #66 primary jet, put in a yellow sec spring
and drill out the sec metering plate metering holes about .004"
Get a K&N stub stack. This will up the carb flow about 60cfm.

HardCore Hot Rods

Ok cool. Would the 4010 carb be worth more to resell than the 1850 though? I currently have a list #6619 600cfm holley on my engine right now, and from what I can tell its exactly the same as the spare 1850 I have (the one I'd trade) except the 6619 has electric choke. So if I traded this spare 1850 I have for the 4010 could I make more money off the 750DP than for the 600? Would there be any performance benifit switching the 6619 for the 1850, or am I correct that they are essentially the same carb? Thanks.

The 4010 is a squarebore, and a fine carb. I bought one when they first came out, and it really had noticeably more throttle response than a plain Holley. The annular discharge boosters make for good response. I think a 750 dp 4010 would run like a raped ape. I would trade for it in a heartbeat. The only thing with those carbs is that the squirters seem a tad small from the factory. You may have to buy the 3 pack kit for $25 and step up a notch, otherwise I think it will run fine.

The 4010 is a squarebore, and a fine carb. I bought one when they first came out, and it really had noticeably more throttle response than a plain Holley. The annular discharge boosters make for good response. I think a 750 dp 4010 would run like a raped ape. I would trade for it in a heartbeat. The only thing with those carbs is that the squirters seem a tad small from the factory. You may have to buy the 3 pack kit for $25 and step up a notch, otherwise I think it will run fine.