Looking for really good carb tech to rebuild / set-up my Holley 650 dp

[Gumball]

Pro Systems is on my list, but I'd like to hear about other skilled Holley techs.

I have a Holley 650 dp that has been okay, but I'd really like to get it rebuilt and optimized for my engine - sort of a "blueprint" and flow test.

Look forward to hearing your ideas!!!

[NAZ]

The Carb Shop in CA. Google them.

[Railroad]

If you want to optimize a carb, I would consider having the a/f ratio data logged. Most dyno s have a tail pipe sniffer, which can be adjusted for, or you can have a wide band sensor bung welded into your exhaust.
I do not see much in a rebuild that you could not do yourself. Not that your specific engine would change any of your goals, but I am interested in what combination you are running. Good luck,

[edwardb]

Pro Systems gets a lot of great reviews. So they obviously know what they're doing. But be aware they will only work on non-choke carbs. I talked to them about tuning the Q-F 750 DP in #7750, and since it was an electric choke version, they declined to work on it. Told me they weren't set up to do carbs with chokes.

X2 on welding in a bung and tuning it with a wideband. That's what I ended up doing and the results were excellent. It was cheaper than having someone else do it (even buying the wideband) and learned a lot in the process. The carbs themselves are pretty simple and easy to work on. Just takes the right combination of tuning bits. Followed Wayne's instructions: http://www.ffcars.com/forums/17-factory-five-roadsters/273476-carb-tuning-101-a.html

[Gumball]

Thanks guys - going to tackle the rebuild myself and then take it to a local dyno for tuning.

[Dan Babb]

What's going on with your Mustang project?

[Railroad]

Here are a couple of good reading sites for Holleys
http://documents.holley.com/199r7849-2rev1.pdf
http://www.bob2000.com/carb.htm
One site does advertise his info, but what is in the site is helpful, maybe no violation of rules.

[Railroad]

You might want to dyno first, then tune, unless you have a problem now.

[NAZ]

If you're going to tackle this yourself you will need several items that range from minimal cost to expensive if you want to do it right. Tuning carbs is actually fun but does take some effort and is not cheap. You will get out of it just what you put into it -- there are no short cuts. Start with purchasing Mike Ulrich's book "Holley Carbs, Manifolds, & Fuel Injection" at the very least. This will set you back less than ten bucks and provide a wealth of information on Holley carbs and Holley clones such as Quick Fuel. Better yet is David Vizard's "Super Tune and Modify Holley Carbs". You have a great carb -- the 4150 "Double Pumper" is easy to work with but you're going to need gaskets and a variety of parts such as main jets, power valves, squirters, accelerator pump cams, etc. to work with. Tuning is an iterative process and not limited to just turning the idle mixture screws. If you show up to the dyno operator's shop without parts you better hope he has them or you're wasting your money on dyno time. If you think this is something you might do more than once then purchasing your own O2 meter will save you $$ in the long run as you won't need a dyno operator to tune your carb for you. You don't need a dyno or an O2 meter to tune a carb but these tools really make getting it right a lot easier than the old school methods we used to use. Have fun and learn as you go. Once you're done you'll understand why the new self tuning EFI systems are so popular. The first cost seems higher for these but once you factor in all the parts & tools needed to get a carb dialed in perfect you'll see that the EFI system are a great value for most folks.

[Gromit]

Given the attention to detail you've demonstrated in your build I would think you should be able to do it your self these carbs are well documented and really not that difficult to work on. good recommendations above re A/F bung and wideband O2 and having all the Bits before you go to a dyno shop.

Here is my one caution / recommendation. in a typical rebuild kit there can be a number of gaskets that go between the main body and the jet / power valve body. I've bumped into more than a couple of swap meet carbs that some ya-hoo self rebuilt and they did not pay close attention to those gaskets. Make sure when you pull yours apart you match up those gaskets hole for hole. I put the old and the new on top of each other and look at them from both sides. other than that make sure its clean clean clean..

carb tuning is just another one of those I did it my self opportunities these cars have to offer.

Chris AKA Gromit

[Raceral]

Look up Baldwin Performance Carburetor in Thomasville Nc... They know their stuff

[CraigS]

Given the attention to detail you've demonstrated in your build I would think you should be able to do it your self these carbs are well documented and really not that difficult to work on. good recommendations above re A/F bung and wideband O2 and having all the Bits before you go to a dyno shop.

Here is my one caution / recommendation. in a typical rebuild kit there can be a number of gaskets that go between the main body and the jet / power valve body. I've bumped into more than a couple of swap meet carbs that some ya-hoo self rebuilt and they did not pay close attention to those gaskets. Make sure when you pull yours apart you match up those gaskets hole for hole. I put the old and the new on top of each other and look at them from both sides. other than that make sure its clean clean clean..

carb tuning is just another one of those I did it my self opportunities these cars have to offer.

Chris AKA Gromit

I agree. I thought all the gaskets were the same until I did the matching like Gromit - ooops, there are a couple of varieties. Also spens a little extra to get the re-useable versions. They aren't reusable for ever but you can get 4-5 times out of them. Also get a nut driver to tighten the float bowl screws and go easy on them. No wrench and no ratchet needed. Not fun messing up the threads in the main body.

[Gromit]

X2 on the reusable gaskets. my first time through one of these carbs I thought buy the cheap gaskets because your going to be replacing them a lot. that was wrong thinking and $ foolish. First issue once they heat cycled they welded onto the parts and tore during the first jet change. Second issue in short order they actually swelled and moved blocking some of the ports. causing a good running rebuild to go sour. Been a while since I've done one so I don't have a current recommendation but if you have a choice get the better quality gaskets.

and another tool. a good quality vacuum gauge. you'll want to get your cruising vacuum to put in the correct power valve(s)

Chris