ok my friends got a 95trans am which he just installed an lt4 kit from summit and some 1.6rr's, car idles good and sounds good, no misfires or anything, but took it for a drive and it bogs rediculously below 2k and really nicly takes off after 2.500 rpms, he has an electric waterpump, intake, and full exhaust. I told him he will need to get a tune. Is there anything else that could be causing this? the cam is slightly over 500 so i was also wondering if he maybe just doesn't have enought supporting mods for this cam? i don't no the exact specs of the cam though. o yeah he also has the lt4 intake manifold on it now.

any suggestions as to what this could be? or am i on track with the tune part.

 

Does the LT4 intake match the heads?

 

cam surge maybe? i bet a tune would help alot

 

i am not sure if the intake matches the heads, i wasn't there for the intalls, would it be easy to tell if it didn't with everything already installed? Also i thought the lt4 intake manifold from summit would match right up on the lt1's stock heads or am i wrong here?

 

LT4 stuff has different ports i believe, the heads and intake are usually used in combo for that reason.

 

The GM LT4 intake has the same ports and plenum as the LT1 intake making buying one for use on untouched LT1 heads a waste of money and flat out a mistake that could be avoided with just the slightest bit of research BEFOREHAND. It has more material above the ports to seal to the LT4 heads which have TALLER not raised ports. To get it to seal to LT1 heads you either need to remove material from the intake or the LT1 head valvecover rail, if you remove the material from the intake you destroy all potential upgrade potential it HAD when port matched to LT4 heads because you took away the material needed to do so.

I would look at two things, one depending what was done or not done to make the LT4 intake fit could be a big vacuum leak at the intake to head mating surface.
The tune is absolutely a problem and is a good mod on a stock car, should not so any real mods without proper programming.

Not sure if the LT4 Edelbrock intake would fit but am sure it would not be a good thing to put on stock LT1 heads. You guys need to read more and wrench less, get more for you mod buck that way.

 

Check the knocks counts with a scanner tool; excessive knock will pull timing and cause the car to bog.