Dual carb 350 Chevy

[Tahiti350]

I picked up a Edelbrock C-21 dual quad dual plane manifold I'd like to put on the 350 in the Tahiti. Edelbrock shows a powerband of 1500-6200, same as the Performer RPM. I am considering a pair of Holley 390 carbs, a cam similar to the Comp 280H, decent aftermarket heads with 64-67 cc chambers for about 9.5-9.8-1 compression, and Bassett headers. This will be in my '80 Tahiti with an OMC 800 I/O.
Anyone have input on the combination, or experience with a similar combo?

[Moneypitt]

I couldn't find any C21 intake in the catalog, but they do show a C26 for SBC. However if the carb spacing is anything like the other Edlebrock designs Holleys will not fit. The C26 SBC and the C66 BBC manifolds require AFB style carbs because the mounts are too close together for Holleys to fit, even sideways.......MP

[GofastRacer]

Yep, those intakes were made for Carter AFB type carbs, Holleys will not fit!..

[Tahiti350]

Yep, your right, C-26. Thanks for the info on the Holley no go. If I remember right the smallest AFB style carbs are 500 CFM each, correct? How will that much carburation work on a warmed over 350?

[Moneypitt]

Those AFBs have a vacuum operated upper butterfly in the mechanical secondary bores. On large cube motors back in the 60s the dual AFBs were the hot ticket, 409 chevys, 421 Pontiacs, and an Offy on a big Olds. BUT, for a 350, I don't know, it'll be like flushing a toilet with a partially clogged sewer line. I'm not saying it won't work, or look really cool, it will just take some serious carb dialing, jetting, metering rods and vacuum springs to prevent a huge stubble in the mid range. Once the motor starts to flow through open exhaust, (you do have OPEN exhaust? right) it will get on the pipe. AFBs are simple carbs when used in simple applications, but 2 of them? You either know what you're doing now, or you will by the time you get through messing with these two. Go for it dude! We'll help you out......Kinda like hold my beer and watch this!!!......MP

[Beer-30]

I am considering a pair of Holley 390 carbs
So, why not just run a 780 Holley, and only have one carb to tune?

[FASTRAT]

I picked up a Edelbrock C-21 dual quad dual plane manifold I'd like to put on the 350 in the Tahiti. Edelbrock shows a powerband of 1500-6200, same as the Performer RPM. I am considering a pair of Holley 390 carbs, a cam similar to the Comp 280H, decent aftermarket heads with 64-67 cc chambers for about 9.5-9.8-1 compression, and Bassett headers. This will be in my '80 Tahiti with an OMC 800 I/O.
Anyone have input on the combination, or experience with a similar combo?
oh yeah...now we are talkin' :)...i have run a set-up like that on a stock 350 with a comp cam 270H & a set of early 2.02 FI heads...worked great...i used the Edelbrock #1404 500cfm carbs with no mods to them (choke plates etc removed)...they have the smallest main jet (.086)...i put a 1" 4 hole spacer (phonolic) under them to raise them up & keep the heat off the carbs...i hooked the 2 carbs together with non progressive linkage...i used the Edelbrock (hard to find..used) 2x4 oval air cleaner...u could use V-stacks or a custom scoop...i think it would turn heads...ya gotta give it a shot...a 1 of a kind...shop EBay for the carbs or RacingJunk.com...just my .02 cents
fastrat
p.s. if u go this route...i can send u a drawing of the bottom of the air cleaner base...so u can get the correct spaceing between the carbs & make a real nice scoop for urself !!!

[Tahiti350]

Okay, so two 500's, more compression, more cam (than the mild RV grind that's in it now), Bassett O.T.'s, and some tuning. Sounds doable. I've got the cam, manifold, headers and flange adapters, just need the banderlog valve, plumbing, carbs, progressive linkage, and one more K&N velocity stack/filter assy. Should be up and running again by April, if I get started on it soon. Right now it's too cold, and I'm waiting for the tax return, anyway
As for just running a single carb, I have that now, and it runs quite well (59.4 GPS). 1409 Eledbrock on a Performer RPM, with the OSCO risers and OT pipes. Just looking for a little more (speed, Flash, attention).

[sweet-v]

Didn't carter make a 400 cfm?
Also smaller in the Corvette 2x4..... :argue: