Holley Carburetor

[Khorne11]

Is there a specific Holley any of you have found that works well with a mildly modified 302 engine? My mechanic recommended a Holley 750, he said it would improve my gas mileage and on road performance. I am 95% a road warrior with just some basic trails, mud holes and camping trips.

This is the specific model:

http://www.summitracing.com/parts/HLY-65-3310/

Any advice would be appreciated.

Thanks!

 

[Justafordguy]

I think that's way too big for a mild 302. I would say 600 cfm or less. They came stock with less than 300 cfm.

 

[JimAndA72]

My "mechanic" (not really a good word for this guy) recommended a Speed Demon 650 for my built 302. After professional tuning, that thing made my eyes burn even when I was outside. Anything bigger than a 600 is way too much on a street rig. Now I'm running a Holley Street Avenger 570. Still a little more fine tuning to do, but it's running really good. Keep in mind that everything will need to be adjusted even though Holley says to just bolt them on and drive.

 

[bad 68]

I second the 570 Street Avenger for your application. That carb is big enough to feed your 302 up to around 7000 rpm.

 

[ElkhartBronco]

http://www.summitracing.com/expertadvice/popup.aspx?Control=CFMCalculator

Here is a CFM calculator to help you better decide what size carb you want to run

 

[Buldozer]

Yep, your getting good advise, 750 is way to big. Go down to a 600 or less for your mild 302 and you will be fine. Truck Avenger if you want to trail ride on off camber grades....

 

[broncnaz]

X3 on the 750 being way to much especailly for a bronco. If you were all out racing with a engine built for it then 750 might be ok. 600 is very good a little smaller is better but not many choices on the smaller ones. a 650/670 is about as big as I would go on a 302.

On a side note 2barrel carbs are rated differently than 4v carbs. You really cant compare 2v and 4v CFM ratings. One other thing is that a 600 cfm 4v carb is likely to have smaller pirmaries than the stock 2v carb had so lowend throttle response tends to be better. so really most of the time your running around on 1/2 a 4v carb really not different than a 2v carb until you need the extra are then the secondaries open.

 

[Broncobowsher]

X4 750 too big
600ish CFM vacuum secondary is a good choice.

 

[Gerbow]

I second the 570 Street Avenger for your application. That carb is big enough to feed your 302 up to around 7000 rpm.

how do you like this ST 570? I am thinking of going this route on Holley advice, telling me this is the right carb for me.

 

[bad 68]

great street carb. My experience comes from a 85 5.0 Mustang. Really runs great on that engine. Truck Avenger doesn't run as cleanly at all throttle positions and engine temperatures but does Off Road great, if that makes any sence?

 

[Khorne11]

Thank you for all the advice, what do you guys think of electronic choke?

 

[JimAndA72]

Thank you for all the advice, what do you guys think of electronic choke?

I'm having a hard time making up my mind. I've been having a hard time getting it adjusted just right. I bought the manual choke assembly a couple months ago and still haven't put it on. Hoping I can get the electric choke set just right. If not, I'll put on the manual.

 

[BlackCat4]

750 is to Big I have à 600 holly 4brl and love it .

 

[mtfit]

I had a local carb guy (Nascar carb builder) build me a Holley 2 barrel for last rig, worked great offroad.

 

[Wyflyer]

750 is way too big, like the others said something in the 500-600 range.
I am partial to Barry Grant Demon carbs, this is what i'd buy
http://www.barrygrant.com/demon/default.aspx?page=6

 

[bluemonday]

I am putting a 600 cfm. I have to install it this weekend. Will let you know. Sorry it was 500 cfm. 2 barrel 3200 series. Smoothest my bronco ever sounded.

 

[Justafordguy]

I had a local carb guy (Nascar carb builder) build me a Holley 2 barrel for last rig, worked great offroad.

I wonder what he did to it? My Holley 2 bbl is horrible off road.?:?

 

[1970mule]

Yeah ANYTHING OVER 600CFM, IS TOo much. look at the demon junior i heard good things.

 

[BronCowie]

Thank you for all the advice, what do you guys think of electronic choke?

I'm all for manual chokes.

 

[Khorne11]

Called Holley today and discussed what I was hearing on the forums and from my mechanic. He tends to agree with y'all but did say a good compromise that would work well with my 302 is a 670 Avenger. He mentioned it was electric choke and if I deceided later I wanted to take it offroading I would be good to go.

Thoughts on this proposal?