Hey all. I have a 1996 Impala ss with a 383 bottomend isnt really important but i think i may have really messed up my top end. It is not making near as much power as it should.heres the rundown.

heads- Bone stock LT4
springs CM motorsports.
LT4 intake
Cam CC236 248 520 560 114+4
Neal racing 3500 stall 10 inch
3.73 gear
new magnecores new opti
30 lb svo injectors
no crossed wires lol

thing barely made 290 to the wheels. and if i punch it in 3rd it feels like it is dead like i got a stock cam or something.The af is right on with the spark and it had a wideband tune to improve to 290 from 240 with herers base tune.


Any and all ideas are welcome. I think i hae it a tooth off but damn if it dont run decent.

I am gona pull the cam i think i over cammed it. And oh i dont plan on spraying it any time soon cam was recommended to me by combination motorsports. I just got what they said.

 

Yeah, I think something went wrong with the installation of one of the parts. Good luck, man.

 

You,re not over cammed, you have a top end problem. Either coil bind (doubtful) or push rod binding, or springs hitting rockers, or collapsed lifter. Check all the conditions on the head. Look real close to see if the push rods are touching the head all through the movement of the rods. I didn't see what ratio rockers you were running (or did you mean stock rockers also when you said bone stock heads)? You may also want to degree the cam instead of removing it (can be done even with the heads on although tougher) to see if the cam is a tooth off (although doubtful).

 

Hey Shane... I also agree that you haven't overcammed it. Check everything that Slopoke said with regards with the top end and degreeing the cam to make sure it installed properly with respect to cam timing/events. That's the only way to know that the cam advertised on the box is the cam you got and if it's ground correctly. If the cam timing is off... that could be why you're down so much power.

Here are other things that are a possibilty... they are remote but anything is possible.
- clog cats... not sure if they are still on
- LT1 intake gaskets rather than LT4's

Good Luck man....

 

The manifold port and gasket openings are the same, but it is a mute point, cuz of the locating dowels in the two gaskets being in different locations. The gaskets won't fit up to the heads, unless the dowels were removed, which is not recomended.

I'm more concerned with the springs. It wasn't mentioned, what springs are being used. The one option of CM springs I'd use with that cam would be the #618s.

The parts he has on now are noted, but specifically, what parts were changed? The guy stated he has 'messed up' his top end. That tells me he is comparing the results to some previous combo used.