I have a 12a street ported engine (rebuilt 4,000 miles ago) with a racing beat intake manifold and holley 600 carb setup with a holley fuel pump (the "red" one) delivering 7 psi... The car has NO type of power... I'd go as far as to say if I went back in time and raced the original stock car 3 years ago as I bought it, it would beat me in the 1/4 mile by a car length... It doesn't have power, and there is an especially noticeable power leveling out after 5,000 rpms... My mechanic says it has to be the exhaust holding the car back, not allowing enough flow... I have headers and a prima flow muffler on the car right now... This upcoming weeekend he is going to extend the headers (they will not connect into 1 tube as they do now) and have 2 2" pipes running all the way to the u-bend over the rear before the muffler,,, he will then tune the car and raise the jet# that the carb has right now.... And after this long story that I just told, my question is, is it resonable that what could be holding my car back is the exhaust??? between the headers and muffler right now is a hollowed out universal cat and a stock pipe... Any suggestions, advice, or references to a knowledged (reasonably priced- I'm on a college budget) first gen mechanic in the northern new jersey area would be greatly appreciated... Thanks...

:unsure:

 

I need to clarify, when I say NO power, I mean no additional power to that of stock power.

 

well if you got headers and exhaust done you should feel a difference especially with a street port an a holley setup. maybe your carb isnt tuned right or your timing is off. now you say its street ported. whoever did it for you should of adjusted the timing on the distributor if he didnt your car is gonna run like ****.

 

Wut are you using for spark?

And yeah advance your timing some..and re adjust the carb..

check floats..fuel/air mixture..



What is wrong? Is it studdering @ high rpms?

Not enuff fuel?



How big is your exhast..on a street port it should be no smaller than 2.1/2

 

4 head ngk plugs,,, i changed them about a year ago,,, which was like 4 months before the rebuild... should i change them??? i have morrosso wires that are approaching 20k miles on them,,, should i change those???

When I floor it,,, the engine sounds like it's doing a whole lot of work,,, but it accelerates like my father's geo prizm.... it doesn't studder at all... the most noticeable lack of power is in first gear,,, and especially at high rpm's in any gear,, about 5k and beyond...

I have a gauge, but not a regulator (i should get one right??),, and it measures the 7lbs being delivered by the red holley pump... The mechanic that did the rebuild put the lowest possible jet without, as he said, doing harm to the engine... once he installs this 2 2" tube set up i was talking about, he will then put a higher jet number to compensate for the exhaust flow which will be then be available... that's the way he explained it, does that make sense??? The exhaust now is the header, then the stock piping which if i'm not mistaken is 1and7/8 inches, then the primaflow muffler.?.?.

and he did adjust the timing... :flush:

 

Incorrect porting perhaps? What templates did he use?