slow89

im just about done building my motor its a 355 with flat top pistions has the comp cams xe 284 cam .510 lift with 284/296 duration. vortec heads with a 3angle valve job and an edelbrock rpm airgap intake. what kinda carb do yall recomend the car will mainly be a street car but will see the strip once or twice a month. hears the carb i was looking at http://www.jegs.com/p/Proform/764248/10002/-1 the 750 mecanical secondary one. What do yall think? what carb do you recomend for my motor?

five7kid

iTrader: (14)

I was under the impression you had emissions inspection/testing in the D-FW area. That would be a hard combo to get through that process.

The Proform is a decent carb. It should support that engine just fine.

I'm a little more concerned about your Vortec heads handling the XE284. What else was done to the heads besides a 3-angle valve job?

slow89

im not worried about the emmisons. i can get the sticker from some people.
the heads have been completly rebult and resurfaced also has different valve springs for the bigger lift cam and have already been shimmed for the cam.
im not worried about the heads just the best carb for my application?

sweetaq

iTrader: (1)

Those vortechs are going to handle that much lift...you must have done some machining to them then. Any port work done. The more info you can give about those heads the better people will be able to help you with your question.

I have a xe284 with some ported double humps and a rm intake and I am running a 750dp with good results so far but the heads are probably holding me back.

slow89

the heads are stock besides the the 3-angle and different springs. they also have guid plates if that makes a difference and some 1.5 roller rockes

five7kid

iTrader: (14)

That's what we're getting at. Typical factory Vortec heads are only good for .480" lift even with springs that can handle more lift, unless modifications are made to the top of the valve guides. Better get valve travel on the head itself (valves installed, retainers and valve seals you're going to use installed, no springs) measured for each valve. If you don't, you're likely to bend pushrods, float valves, or wipe out the cam.

slow89

well thats all i got i dont have the money to be changing the heads. so what kinda carb should i use?

Apeiron

It doesn't matter what carb you have if your cam has too much lift for the heads.

slow89

im not the only one who has ever used this setup ive read that other people have and have had no problems with it????

Apeiron

Only if their heads are modified for the increase in lift.

slow89

ok well what do i need to do to modified my heads so i can use the cam?

five7kid

iTrader: (14)

Like we already said, have the tops of the guides cut down to increase the distance between the top of the guide and the bottom of the retainer. It's also the right time to reduce the OD of the guide so you can put double springs on. This is a heads-off-and-disassembled operation. It can be done with a single cutting tool so there's only one operation for each valve. The advantage of this is you can use better springs with the OD of the guide reduced, and positive-type valve stem seals for better sealing.

There are also reports of springs and retainers that will provide increased valve travel, but it makes more sense to me to do the machining and get it right.

Rayzor32

iTrader: (1)

i've got a .525 lift cam on the vortec heads and it works fine though the heads were machined for it running single springs. I'm in the same boat as you pretty much. I've got a holley 3310 on right now, its a good carb but I don't like the vacuum secondaries and it won't hold the tune it had before. I want to try a 750 eldebrock see how that works I hear they are great for the street everyone runs them around here. I always been around holley's though I want to get the new street hp 650 double pumper. The 750 might be too big for street use.

Apeiron

People use Edelbrocks because they're cheap and shiny, not because they're good. You'd have better results with a DP. With a cam that big, a 750 probably isn't too much, even on the street.

Rayzor32

iTrader: (1)

i know a 750 eldebrock wouldn't be too much but you don't think the double pumper would? The 3310 i got has crap bottom end/throttle response/fuel economy so I'm thinking that the 650 would be better. Though car craft built the exact same motor combo I have they used a 750DP speed demon (they always use demons wtf).

The eldebrocks are cheap yes the guy down the street sells them for 50 a piece but they arent shiny. I figure they are worth trying so I can get my own opinion on them whether they are good or not, a lot of my friends all like them for street use.

Apeiron

You've probably got a crap bottom end and fuel economy because of the size of the cam, not the carb.

Rayzor32

iTrader: (1)

the cam is pretty mild its only got a "high" lift because of the 1.6 rocker arms. duration at 50 is 218/228. advertised is 279/287 though im not sure how important that number is. I get 15" of vacuum.

slow89

well i talked to the shop that put the motor togather they said when they were assembling the motor they checked all the clearences in the head and it was good to go so idk if im just lucky or what but the heads ARE going to work