i have a 1970 chvevelle s.s. with a 396/402 bored out/TH 400 tranny, and i just threw on a 750 cfm edlebrock carb and i added a fuel filter.

it runs like a dog...without legs.

i am lacking major power and the idle is tweaky.

--one example for instance--
> i get on the gas and the engine cuts out until i let go of the pedal.....soooo i have just about zero acceleration when it comes to speedin up.




any tips would be great. thanks.

Hello to you,
First check your air fuel mixture on your carb. I really prefer Holley carbs you will get better performance out of a holley. If your carb is set correctly check your fuel pump. I had that problem with my 70' chevelle and my fuel pump was bad. definitaley sounds like a fuel problem... GOOD LUCK!!!

Why do you have the 396, I would have went with the LS6 454. And on the carb issue Holleys are nothing but trouble right out of the box. Edelbrock can't be beat. And i have a question, what would be the best transmission to bolt onto a blown 454 in a 70?

Why do you have the 396, I would have went with the LS6 454.


are you 12????

"why would you go with the LS6 454, i would have picked the saturn V rocket"

dont get me wrong im a major fan of the LS6 myself, and if you have the money to be able to make that kind of choice than im happy for you, but remember that not everyone does, so try not to be a dick about it. And perhaps he dosnt want the 454 for other reasons. I for one am building a 302cid smallblock rather than the more popular 350, 355, 383, 400, 406, 427, and even 454 small blocks. I have my reasons, im sure he does too.

in regard to the best tranny to go behind a blown 454, it depends on what you are using the vehcile for and weather you want a manual or automatic tranny.

In reference to the problem at hand. im assuming that the engine was running fine before you put the new carb and fuel filter on it. If that is the case then the pump is probly fine.

I could be wrong, but i thought that the edelbrock carbs had a built in fuel filter, so by adding another one, you are filtering the fuel twice, and adding more resistance in the line which could be limiting fuel flow into the carb. Are you sure the carb is set up correctly, it kinda sounds like you have your metering jets set up too small and you are leaning out the mixture when you open up the butterflys.

As 89IROC&RS said, was the car running fine before you changed carbs? (I assume it had a Q-Jet before?).
It sounds like you are getting no "shot" of fuel from the accelerator pump in the carb. With engine "Off", peek down throat of carb, and actuate the throttle - is it squirting a stream of fuel down each primary barrel? Is the float level set properly? Fuel pressure? How about if you gently ease on the throttle, will it eventually accelerate decently? Share some more info, and we will gladly try to help.
PS: Forget the LS6, how 'bout the new ZZ572 Crate Engines? (Just kidding, lol, they are awesome Big-Blocks, rated at 620 & 720 HP, but they put out over 60HP more than that, and the GM Performance Parts website has a cool video clip, complete with sounds of that beast on the Dyno!!).
Good luck, -Jim.