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I missed it somewhere I guess. Gary why are you messing around with Holley carbs suddenly? I thought you liked the Carter/Edelbrocks?
Holley has a fairly good website, and they used to have a big chart over there that you could look up all the original jetting and power valve sizes that the carbs had from the factory. They usually shoot straight down the middle to cover most engines and they always recommend you start there.
For reference, the little 600cfm 4160's I always run have #66 primary jets with the metering plate on the secondaries.
Dave - This is a long way around, chasing Jim's wabbit, but I found a guy on CL that has a 600 CFM Summit carb, the old 4100, that wants to trade for a 750 Holley or Carterbrock which is bolt-on ready. I've been wondering about the Summit carb, more of which later, so contacted the guy. He was interested but stressed the carb had to be ready as his is on his vehicle - whatever that is. So I pulled the 750 I had apart and discovered it is, literally, junk. Something has caused the main body to delaminate to the point it can't even be milled to clean it up - it is like trying to mill potato chips.
So, I've been on the lookout for a replacement body when another guy advertised on CL a 750 Holley, 625 Carter AFB, and a 4GC for $85, and all three had been taken off of operating engines when put on the shelf. So, I bought them knowing the Holley didn't have a choke shaft or butterfly but that the flakey carb did as well as an e-choke. And, both the Carter and Rochester look good, so I really couldn't go wrong.
However, in the interim I've realized that the guy w/the Summit carb hasn't communicated in a few days and I've never seen a pic of his carb, though he's said he'll send some. So, I'm coming to the conclusion that I'm building a 750 Holley for myself. Well, why not try it during the dyno run on Dad's engine. Yes, I have a book that tells the stock jetting for a 3310-2, but I was looking for suggested jetting for a 550 HP 400. Some starting point that'll get me in the ball park.
Now, for the 4100: I have a 600 CFM 4160 Holley and a 600 CFM 1406 Edelbrock. And I have an AEM wideband AFR meter. Why not run a test of all three 600's to see what jetting they need to get dialed in on Rusty and then see what I get in MPG and acceleration. Oh yes, I have Dynolicious on the iPhone which will check acceleration. So, it seems like a fun project.
Jim - You are aware that I'm aware that you are aware that I'm aware that Holley owns Demon.
Even with a 550hp 400, I would start with or very near stock jetting and power valve. I believe the 750 may serve you better than a 600 if you are shooting for that high of a hp number, even though the "books" and theories say a 600 is big enough. The 600cfm runs fine for everyday use, but I once had one on a 350 chevy that had some guts, and could tell the 600 was holding it back a little bit. A larger quadrajet let that engine run better(max power) than the 600 did.
Dave - I have a 750 CFM Street Demon destined for Dad's engine. It is the one that Tim dyno'd on an iron-headed 400 with a flat-tappet cam, with the results shown below. So I'll start with the Street Demon jetted stock, as it was for those pulls. But wondered if that's where I should start with a Holley. Perhaps so.
But, back to the 600 carbs, that's all for Rusty. I got him with a stock Holley 1460 on him and it was extremely rich. I've swapped to a stock Eddy 1406 which really helped the off-idle as well economy, and have subsequently improved the economy by tuning with the AFR meter. But, I've been wondering about using Rusty as a test bed for dialing in the Holley and Summit carbs and seeing how the three different carbs compare when properly set up.
Well, it is almost time to close out this thread. (And you didn't think I knew how?) I got the 3310-2 together today with the bits from the 80508-3, as described below. So, all that remains is to find out if the guy with the Summit carb wants it or if I'm going to set it up for testing on Dad's engine. If the guy wants it I'll rebuild it using the kit I have and the secondary metering plate that came in the 80508-3. But if it is going to be mine I'll use the secondary metering block that came on this carb as it gives much more adjustability.
Anyway, I reamed out the air horn on the 3310-2 to take the larger choke shaft from the 80508-3. Fortunately I had the right reamer and it was long enough to span both holes, ensuring the holes are aligned, so installing the choke shaft and butterfly was easy. Then I installed the choke housing and adjusted it to the index as it was backed off the whole way and the choke wasn't coming on. Now the choke works as smoothly as a new one.
Then I installed the 80508-3's throttle body since it's fast idle screw works properly with the choke mechanism. But, I suddenly wondered if there are any differences between the two so measured them - none. So I moved on to the metering plates and bowls, and used the 80508-3's primary metering block as it has the jetting I want it to have. Now it is all buttoned-up waiting to get thoroughly cleaned and new gaskets/needles/seats/etc - depending on whose it is going to be.
It has oversize primary boosters in what is basically a 780 (3310) body, bringing the primary size down to 345 cfm. Yes, a 460 runs great with it, we had one on a 1970 Mark III. I know where it is, I had it in my hand last time I was in NN.
A 3310 would have the front/rear-hung floats, right? And a secondary metering block, not a plate - right? I would think the larger boosters would help drivability at part throttle.
The floats reminded me of some reading I did yesterday. We took the GLK in for its 20K service and had 3+ hours to kill, so I chose Barnes & Noble. I mean, how can you go wrong with a Starbucks and lots of magazines and books to look at. One I perused was the one on McQueen's cars, and at one point he was test-driving cars for a magazine. He drew an early Cobra and one comment was that they'd used side-hung floats and he could feel the engine run out of fuel on the corners. But, knowing Carroll, he was sure that would be solved soon. Now I have an urge to watch Bullitt, The Great Escape, and Le Mans.
