Well, it seems my throttle shaft has way too much play on my existing Holley vacuum secondary 750. So, I'm going to shop for a replacement Holley.

I'm VERY comfortable adjusting and tearing into the Holley I have now, so that shouldn't be a problem for me.

Current combo:
402, bored 30 over.
mild cam - roughly 475 lift but will be changing that in the years to come.
1-3/4" headers, 2 1-2" exhaust.
Automatic
3:23 rear gears
No idea what my compression ratio is.
Stock heads with larger valves.
Strictly street use.

Any recommendations on which model Holley I should consider? All input would be appreciated. I'm thinking a 750 double pumper, but I'm just not sure.

I bet a 750 double pumper would be just right, how high of rpm does this engine see?

X,
Personally I would stick to a vacuum secondary carb for strictly street. If you are happy with the performance of your present setup, why not just get a new base plate for you carb ?? If you insist on a complete new carb, go with the same thing you have, if you are happy with it. Your combination is not radical enough to need anything more than a 750 vac secondary carb. My 67 Camaro I used to race went 10.70's at 126 mph with an unmodified 3310-1 Holley.
Just my opinion,

Wow, you guys are quick.

Badbob, I don't see much over 5k - but once I do a cam swap that may move up to 6k, but not that often.

Bill, I know what you mean about the vacuum secondaries. While I am happy with my current 3310 (or was before I started having trouble) I also believe that the vacuum secondary 3310's make the least power. Car craft or someone did a test of the various holley's not that long ago, and the 3310 came in at the bottom of the heap. As a result, if I'm going to buy a new carb I might as well get a few extra ponies out of it at the same time.

Not sure if they tested the new Avengers, though so I wouldn't necessarily rule them out.

Double pumpers rule IMO, an HP750 would really work well I bet. Just keep your foot out of it if you want any kind of mileage

Change the shaft bushings. It is super easy once you get the throttle blades out.

Proform has billet 750 base plates for $130. They also have replacement bodies for $99.

You know, I didn't really think about fixing the current one.

Since I now have an excuse to get a little more go juice by getting a "better" carb, I thought I would see what everyone thought was a good bet.

Gas mileage? What's that? ;)

I didn't know you could buy a replacement baseplate. My uncle gave me a #3310 with one corner of the baseplate moderately cracked...looks like it was overtightened. Is Proform the only source for a replacement? Can you get them direct from Holley? I didn't see replacement baseplates on the Holley website.

I picked up 1 MPH consistantly at the track after swapping my 750 double pumper out for a 3310 with my mild 454..a double pumper makes the car "feel" faster because the secondaries can be opened at any time,but just because they open quicker doesn't make the car faster..again,I'm speaking in regards to my experience with a heavy,torquey car that has no gear.

Originally posted by Georgia69:
I didn't know you could buy a replacement baseplate. My uncle gave me a #3310 with one corner of the baseplate moderately cracked...looks like it was overtightened. Is Proform the only source for a replacement? Can you get them direct from Holley? I didn't see replacement baseplates on the Holley website. I guess I was wrong. Summit didn't show a base plate for the vac sec carb. They have them for the DP's. Proform may have them for vac sec but they are not on Summit's site.

Bummer. I don't know if a used carb is worth a new $130 base plate. Maybe I can find a swap meet #3310 with a serviceable base plate

Does anyone have any other input? Basically I'm between a 750 DP or a 750 vacuum secondary. I know someone tested them and the 3310 (750VS) came up at the bottom, but that doesn't necessarily mean it won't work best for my application, as Chris points out.

I'll get Holley's input on this as well, and see where it takes me.

Thanks for all the input so far!

You could always get a new baseplate from a company such as BLP, APD, AED, or Braswell.
http://www.blp.com/Default.asp
http://www.apdracing.com/
http://www.aedperformance.com/
http://www.braswell.com/

Also try TPC http://www.tpcracing.com/

For a little more money you can pick up one that has slabbed (thinned) throttle shafts and button head screws.This gives more airflow and since you have a VS carb you could dial it in to what your engine needs with the VS spring.

Just a thought.

I had an 850 I bought years ago that was cracked on the corner and had it welded and just tuned it with a file, worked just fine. Nice thing about aluminum it can be welded easily even if cast. I'd find a good welder and buy him a six pack then drop it off at the machine shop if you don't want to file it yourself. No big deal IMO.