[pony88]

I have a 88 carbureted mustang. It's a 302 bored 30 over with forged pistons with stock crank and rods. It has a very tall intake with 750 holly carb. I hooked up a Nos cheater system set up for a 100 shot but never used it yet. When I push the pedal all the way to the floor it will studder but when I drive normal or semi aggressive it's ok. I changed the plugs, wires, and had the carb worked on. I was told by someone it could be the intake is too big for my application or maybe the electric fuel pump isn't enough. It's a Mr. Gasket 12s which only has 35 gph and max 7 psi. I don't know the make of the intake but it's probably 3 times as big as a edelbrock performer. Please Help.

 

[DoubleVision]

Is the intake a open plane? Is the carb a vacuum secondary or mechanical? You have set the float levels? What is the extent of mods to your 302?

 

[pony88]

I don't know about the intake being a open plane. What do I look for? The carb is a vacuum secondary and the float levels were set. The engine was bored .30 over, mild port work on the heads, aftermarket forged pistons, intake ,headers, msd ignition system. Thats all the engine mods

 

[Biscuit6447]

I have a 327 with an open intake and a 600 cfm carb. It was great for stop and go, but sacrificed the top end. A bunch of forums here said that a bigger carb would be better for to end. So i got a 750 and had the same problem bogging off idle. after fussing with timing, fuel flow, and carb tuning i finally figured it out. with a 750 carb on a little motor, there isn't enough airflow to engage the primary boost venturies. I figured it out by looking down the carb without the air cleaner on. 600cfm - fuel comes right out, 750 cfm - needs a lot of throttle opening and takes a sec before the engine builds up rpm to draw the fuel in.

hope thats not too confusing.

 

[eloc431962]

Where the carb bolts on the intake, If it has one big open hole it's a single plane, And a dual plane has a spacer and has two sides/ holes where the carb bolts down then it's a dual plane intake. Cole

 

[dawg]

the carb needs more pumpshot
simple as that!
also with oversized intake its best to use a 4 hole carb spacer between intake and carb.
for an explanation go here
http://www.gnetworks.com/v4files/barrygrant/Spacers with images.pdf

 

[Pianoman]

Check the timing before you get mediveal on the carb.
Unless we're talking tunnel ram intake I can't see how a highrise intake would be cause it. I run my 355 CSB with a Weiand Team G single plane and it responds like a cat on meth from idle

 

[454headache]

I agree, check your timing. I had similar issues on my BBC. Turns out it was my timing. I got out the old vacuum gauge and set the timing for max vacuum at idle. Bingo, problems gone.