Carb for a 302

[dagoof]

I'm trying to figure out which carb size / type I need for my 302.

I've good a rebuilt 302. It has:
- Decent compression (9.5 : 1)
- Balanced internals
- Full length Duff headers
- Edelbrock air gap intake (1500-5500 rpm range)
- Lunati Vodoo cam (idle to 5000 rpm range)

Is a 650 or 670 CFM too big for me?

 

[COPPERHEAD85]

650 should work fine.
Good place to start.

 

[dagoof]

I actually have a 600 right now, but people keep telling me that it is too big for a 302.

I've got a terrible dead spot right now. When I mash the go pedal, it almost dies and then it takes off a few seconds latter.

 

[Gotta_gofast]

a holley 570 truck avenger would suit your needs. A 650 is WAY to much. The truck avenger would give you enough fuel and it'll handle "truck abuse" better than a street carb.

 

[COPPERHEAD85]

I had 2 650"s on a 302 and it would take wide open throttle.

 

[85_Ranger4x4]

I had 2 650"s on a 302 and it would take wide open throttle.

Was it similar in specs to the OP's?

If so I bet you had a lot of raw fuel coming out the exhaust.

 

[baddad457]

I actually have a 600 right now, but people keep telling me that it is too big for a 302.

I've got a terrible dead spot right now. When I mash the go pedal, it almost dies and then it takes off a few seconds latter.

Sounds to me like you need to spend some quality time tuning it. Starting with the accellerator pump linkage. If it's a Holley, it likely has too much freeplay between the pump arm and lever. A 600 is perfect. No need to go bigger. Smaller (a 570 Street Avenger is my weapon of choice) would be the better direction, if you wanted a change.

 

[COPPERHEAD85]

A lot more.............lol.

 

[dagoof]

It seems like there is always going to be a lot of debate about how big of carb to use on any given engine.

Holley told me that the 600 that I have is the right size, but I don't particularly like it. I need to go through it, and I suspect that the accelerator pump might be messed up based on the way the truck falls all over itself when you punch it.

I would actually like to get into a 4150 style carb. I like the dual feed setup, and any of the 4150's would let me feed from the passenger side instead of having it in the way of my linkages. Also, I hate the gold/dichromate color. I would rather have a silver/polished aluminum look.

Unfortunately, it looks like the 4150's only come in 570 or 670 cfm or a 650 cfm if I go with a double pumper.

 

[dagoof]

A lot more.............lol.

a lot more what?

 

[dagoof]

For what it it worth......

Here's the engine in question.

 

[JoeyB]

Holy chrome! Your not playing around are you. That's a sweet looking engine. I'm using a 4160 (600 cfm) and it works pretty good. No dead spots when you hit the gas. I have noticed at steeped angles it does run rough, but that's few and far from the typical driving I do. I'm more of a daily driver in town with the occasional 4 wheeling with the kids.

 

[dagoof]

I'm using a 4160 (600 cfm) and it works pretty good. No dead spots when you hit the gas. I have noticed at steeped angles it does run rough, but that's few and far from the typical driving I do. I'm more of a daily driver in town with the occasional 4 wheeling with the kids.

You're running the same carb with no dead spots. I'm starting to think more and more that something is wrong with the accelerator pump or power valve.

I've had the same problem when I get on a steep angle or bouncy ride. I've been looking into getting the one-piece overflow tube and the stiffer float springs off of Holley's truck avenger carb. Has anyone else done this?

 

[COPPERHEAD85]

a lot more what?

Didnt mean to come off in the wrong way so no offence intended.
351W heads with about $3000 worth of work to them
300 duration 500 lift cam.....yada yada

Damn nice job on your install.......

 

[dagoof]

Didnt mean to come off in the wrong way so no offence intended.
351W heads with about $3000 worth of work to them
300 duration 500 lift cam.....yada yada

None taken.

I hadn't seen your first post, and I was just trying to understand what you were talking about.

Double 650's and $3000 heads? Dang! That thing must be a beast. What kind of HP are you getting?