i am wondering what of numbers an LT1 1996 ws6 trans am with the following mods should turn in the 1/4 mile. LT4 intake plenum, LT4 hotcam, hooker longtube headers, borla exhaust w/no cats, BBK throttle body (unknown bore), K&N filter, mild tune, and eagle f1 tires in rear. (on 19 inch c5 wheels). just curious of what kind of numbers this car should turn with these mods because i hear about LT1 cars with mild bolt ons running 12's in the 1/4..i got a best of 13.8 @ 105

How do you know if you have an LT4 intake ? Is it Red ?
LT4 intakes are only compatible with LT4 heads because the port entrance is different then the LT1.
How are you launching the car (are you losing alot of traction) ? What is your 60' time ?
Lots of variables including weather can dictate your times also the 19" wheels are heavier and can slow cars down aswell.

The LT4 intake can actually slow your car down, becuz the ports don't match the LT1 heads. The LT4 cam is milder than the standard LT1 cam if 1.5 rocker arms are used. It would have a good top end charge though...due to the 114 centerline (LT1 uses a 115/117 centerline). The LT1 cam with 1.6 rocker arms has more lift and slightly more duration (same 115/117 centerline), but despite the centerline, is a hotter cam when equipped with 1.6 roller rockers.

The LT4 heads have 190 cc vs 160cc for the LT1 heads. Flow numbers are 240cfm for the LT4 heads and I don't know what the standard LT1 flow numbers are, but it is much less--maybe around 210 or less. The LT1 heads can easily be ported and polished to match the LT4 heads, but it would be very expensive to port match them with the LT4 intake. Best to find some good used LT4 heads (use them unported and unpolished), then install a 94 or 95 LT1 camshaft with 1.6 roller rockers. The net result would be far more low end torque, a humongous top end charge and with Air Flow Research Hydra Rev Kit, a 6,600 rpm rev limit (limited by your engine's crankshaft).

i dont know the EXACT specs because i got it from someone who bought it from the original owner who built it. i been trying to call the guy who built it but he is very hard to get ahold of due to his profession but yes the intake is red, and i looked at the differences online between the LT4 and LT1 intake to tell if hads beenn painted or not and it says on the LT4 that where the manifold meets the heads that it has a bigger lip where the bolts hold it down, which mine has a larger lip also. and it looks like a legit factory powdercoat job. i have been told the heads were changed also but im not exactly positive because the people i got the car from are idiots lol i know the heads are aluminum but from what i understand by what others say, aluminum heads dont mean anything because the stock LT1 has aluminum heads. how can i tell if the heads are LT4 also?? and about the 1/4 mile times i am just wondering what it should run because i dont have my time slips so i cant give exact numbers right now, they are in my car which is at the shop.

Don't know how or what to look for to ID LT4 headcastings. They did have screw in rocker arm studs with a shoulder that the Crane black rocker arms fit onto--no adjustment needed, just torque them down. That might be the only way to identify them. Also check the valve springs--they were a special German steel with an oval cross section to the wire.

If the engine has the entire LT4 setup, then it produces around 330 hp and the 1/4 mile times are actually very good for this setup.

The casting number on the LT4 head is 12363287 and the LT1 casting number is 10128649 or 10128374 on the earlier LT1 engines.

OKAY THANKS GUYS I WILL LOOK INTO THIS WHEN I GET MY CAR BACK. I KNOW THIS IS A DUMB QUESTION, BUT WHERE DO I FIND THESE NUMBERS AT? DO I HAVE TO TAKE THE VALVE COVERS OFF OR ANYTHNG?