olds 455 TR carb choices??

[matt1840]

hey guys.... finishing up my 455 project and its come down to carburator choices...
olds 455 .30 over
9.7:1 compression
comp cam XE274H 230 236 duration .520 .523 lift
mild ported heads
offy tunnel ram
carbs???????????????????????
i was thinkin about the 4160 holley 450's... the summit page says its got mechanical secondaries, but if you read further it says its got vac secondaries, whats up with that??... would this be a good choice for my application??? Ive never tuned hollys before so im opening a new can of worms here. any advice on what i should use?
http://store.summitracing.com/partdetail.asp?autofilter=1&part=HLY%2D0%2D9776&N=700+115&autoview=sku

[DMOORE]

The photo of the carb is a mechanical unit. 900 cfm should be plenty of carb for your motor.
Darrell.

[Moneypitt]

If memory serves me correctly, the 4160 is a metering plate secondary carb, uses a balance tube to feed the rear bowl, and is vac secondary. The 4150 series use a secondary jet block, and can be vac or mechanical secondaries, and double pumper types.......I use 2 Edlebrock 600s on a 455 with an old Offy 2X4 intake with 2" riser blocks....Works well, as the 600s are vac secondary.......And the Olds seldom sees 5500.......MP

[matt1840]

how do the two edelbrocks run??? any kind of hesitation??? i was running a single edelbrock 750 with a torker manifold and had hesitation out of the hole, or if i punched it from cruising speed it would choke out then catch up with itself so to speak. I couldnt seem to get rid of that problem, which is why im looking at the hollys.

[Moneypitt]

how do the two edelbrocks run??? any kind of hesitation??? i was running a single edelbrock 750 with a torker manifold and had hesitation out of the hole, or if i punched it from cruising speed it would choke out then catch up with itself so to speak. I couldnt seem to get rid of that problem, which is why im looking at the hollys.
The transistion is tunable. Even with a (or two Holleys) you may have a bog. The Edlebrock trick kits have metering rods and springs to dial them in. The jets are also available. As I recall, my Olds ran fine after raising the float level a bit.....Adding 2 fuel pumps, one from each tank, to each carb.....eliminated the top end starvation......If you use the Carter style, get the book, read it cover to cover and fine tune it (them) right in........MP