mild roller cam and headers,906 heads.for street only.these cars came from factory with a 600 carb and was running pretty good then, thanks

But no factory 383's came with roller cams or headers.

750cfm no problem at all.

400's came with 850 cfm.

340/360's came with 800 cfm

360's and 400's also came with 2bbl carbs, so that's not a real good indicator.

A roller cam, in and of itself, is no indication of anything. my 87 318 came with a stock roller cam and a 2bbl.

spec's on the engine build would be better.

My experience is that both cams and carbs are better off going a bit more conservative than the opposite for anything "street only".

My RR loves its little 650DP. I have a 750 DP as well but the car doesnt run near as well. Major bogs, hesitation, sputtering, etc. Both carbs were rebuilt by the same guy at the same time. Both were put back to Holley specs with the proper jets. I took the 750 back a second time to have him go thru it again with the guy even driving it with the 750 installed. For some reason my car just likes the 650. Either that, or there's something wrong with the 750 that hasnt been caught yet. My car has headers, mild cam and head work (906's), 4 speed. Who knows.

Oh Lord here we go..
You guys would be doomed running a six pack

My built 383 loves 670 cfm. Tried a 750 and it ran worse. Also have a 650 on a 400 hp 360 and it likes it. Again, tried a 750 and it ran worse. Sometimes I think it is too much air that kills performance as much as the fuel.

I know many hate them, but I have a RARE edelbrock performer 750, that actually works really well on my 383. Lightly worked 906's, rpm intake, mild cam, and headers. That's it.

Same size carb came on the 1st Gen z28 302. Nobody complained about it being too big.

Yours is probably setup wrong for your combo. Find someone that is good with holley carbs to tune it on the car instead of your rebuilder guessing on his workbench.

Bigger carb may need timing advance curve changes to work properly.

My son ran our 1407 Edelbrock 750 on the 302 that was in his wife's Mustang when they got it. Why? It's the only good four barrel we had to get it running on without spending any money. It ran fine, but probably didn't get the fuel mileage that it would have with a smaller carb.

i have a 750DP with annular boosters on the 360 in my car. modest cam, maybe a 272, good compression, hi-rise dual plane intake, it's completely factory tune on the carb right now except i drilled the IFR's and went down a step there, cleaned up the transition and it runs fine on the street.
2.94 gears and maybe a factory high stall converter, flashes to maybe 2500.

The 5.9 in my Duster will pull a vacuum at WOT with the 625 CFM AFB, since finding that out swapped to 750 AFB. Runs 13.0 at 104 mph.

A 750 will be fine on a 383.

I have a Holley street hp 750 on the 400 on my dart and it runs great.

the 750-800 holleys are near perfect for a 383. if tuning skills are lacking it wouldn't make much difference what the "ideal carb" would be; then one would have to rely on random "luck".

i did run a dp6b back in the day. a lot of possibilities here but expensive to do right.

Nope, but lots of comments about soggy bottom ends and not being a very good "street only" car.

I ran a 750 on my 225 when I put a 4bbl intake on it because that was the carb I had.

Did it work? yes.

Was it optimal, not by a long shot.

You could probably take the carb off your lawn mower and get it to "work" too.

Back in the day, EVERYONE knew that a 383 would run much better with the carb from a 440 on top of it. I imagine the carb to use was the one from the higher performance 440. Shoot, that carb was even the right one for 340s!

AFBs and AVSs have a secondary that opens on demand so the carb is only as big as the engine needs. I ran a 600 Holley for several years on my low po 318 with decent mileage and driveability. It ran better with a later 570 Street Avenger but I attribute that to a better fuel curve.

The tune on the carb is more important than the cfm. That's one more reason that fuel injection is so good, at least the ones that use an O2 sensor.

R.

When I bought my RR it had a vac sec 750 that ran like crap. I've spent some time with Holleys. So I jetted it, changed PV and squirters and it ran like a scalded dog for a bone stock, 50,000 mile original 383.

Because my car is so original, I went back to the original 383 AVS (properly jetted) and it probably killed at least 20 HP.

No a 750 is not too much. As said, other makes used that size on much smaller motors from the factory, for a reason! Back in the day, installing a 440 carb on a 383 was worth plenty.

I'm running a mild 383 in a '68 Road Runner. Speed Pro 2315 pistons, stealth heads, 9.7:1, XE 268 cam, Perf. RPM intake, factory HP manifolds with an 1806 (650) Edelbrock. Runs GREAT with a 727/3.23's.

Of course 1st gen Z/28s had soggy bottom ends. It was only a 302 and it had a pretty hot cam. I doubt the 780 carb hurt it too much.