Alright everyone I have a couple questions?

I am going to be gettin a 650cfm carb but I am not sure which one to get and what I all need on it such as vacumn and stuff like that.

Also I know I need a non computer controlled distributor with vacumn advance, but do I need an HEI and do i use my original coil with this?

Thanks for your help.

 

With an automatic transmission, I've always preferred a vacuum secondary carb...the old rule with automatic transmission cars and carbs is use a vacuum secondary carb on cars weighing more then 2800 lbs, and a mechanical secondary carb on auto trannie cars weighing less then 2800 lbs.... But, this is subject to change, too. A highly modified engine, good cam and heads, stoker, etc. may work better with a mechanical secondary carb...

An HEI distrubutor is a good unit, even the factory units work good! Installation and wiring on them is simple! MSD makes some very nice HEI "plug and play" HEI distributors, as well as a bunch of other manufacturer's....

 

is this a stock engine? if it is then i think that a 650 will be a little big. is it a 350 or 305. need a little more info. as for the dizzy. they are readily available and can be gottn new for less than a 100.00.

 

Stock 350. I will be putting heads, cam, and headers on it next summer so I want a carb that will handle that. I can always turn the 650 down.

As for distributor Im thinkin on going with a procomp HEI, I was just wondering if I plug it into my stock coil or not.

 

you will use the wires from your coil to plug into the hei. i did this. the coil is already in the hei-you dont need two of them.

 

You can get a small cap vacuum/mechanical advance distributor that can use your existing coil. Most people, though, when they do this conversion, get a large cap HEI with the coil in the cap.

The stuff about using vacuum secondaries with automatic transmission is just silliness. The issue with mechanical secondaries is the RPMs that you can go WOT without bog. The Holley website has a chart that shows what engine CID can handle what DP carb at what RPMs, and for a 350, it's something like 1300 RPMs - keep the stall above that, and you'll be fine with a 650 DP. In fact, if you match your converter stall to your cam, you'll always be fine with a properly sized (for your engine CID and max RPMs using the RPMs x CID / 3456 formula) DP carb.

A little personal history (before I was "educated" with the above paragraph information): The 396 in the '57, had a q-jet on it until 2001. The converter stalled about 2000 RPMs, it always felt like there was a little bit of bog when I first hit it, and would then get going. In 2001, I put on a Holley 750 VS, and it acted the same way, regardless of what I did with the secondary springs. In 2003, I put on a 650 DP Holley and immediately picked up 2 tenths, even though it still felt like it wouldn't start pulling right away. Then I got a converter that stalled at 2900 RPMs, and suddenly, all those issues went away. Turns out what I thought was bog was really just the point the cam hit its powerband.

Moral of the story: If your converter lets your cam get into its powerband, you won't have a problem with a double pumper carb.

So, add higher stall converter to your list of upgrades. You'll need it whether you go VS or DP (but I'd still recommend a DP carb).