hey guys i know im new to the site but i bought a 95 z awhile back and ive finally saved up a little money i have did my research on many threads here but just cant seem to find the info i need to make the right decision on my car the motor is an lt4 block stroked out to a 396 it has eagle forged rotating assembly balnced and blueprinted it has forged srp pistons and as of right now im not sure of the specs on the cam i was told it was custom but i highly doubt that it has stock lt4 heads that have been ported 2.08/ 1.6 valves comp roller lifters 1.6 ati dampers ceramic coated long tube pacesetters 3 inch y pipe flowmaster a holley 58 mm tb with a lt4 intake also ported its an m6 with 4.10 gears in a stock 10 bolt until next year when i can get a s60 so my questions are what would you put my numbers at right now ( i know its tough w/o cam specs) and what heads and cam should i get to be able to be in the 10s but also be streetable and also this is na the car is in stock trim and the best pass to date with current setup is 11.5 and i dont have the trap speed i lost the sheet sorry and thanks on any input

 

400-450 RWHP Who knows depending on the cam and the extent of the porting on the heads. I would get a dyno tune to get a baseline and take it from there IMO.

 

thanks ahritchie for the quick reply i know its kind of a shot in the dark i wish the po knew more but could you suggest a hyd roller cam and heads that would dip me in the 10s im thinking either afr or ai ecspecially with ai's cam and head combo deal but not sure on what size heads and i can have them help me with the cam

 

i dont think you can fit a 2.08 valve in a stock valve spacing head. needs to be a 60/40 configuration.

 

ok thanks bigcat im not sure to be honest i havent had anything other than the intake off the car to fix a bad lifter im trying to drive it until winter hits here in MI and then do the work as of right now its my dd so is it worth puttin some more money into my lt4 heads or getting a set from afr or ai either way i will be ordering a custom cam and tune

 

Take it back to the track. If it is 11.5 at 115-116 then you need to think about how to add more power, but if it is at 123mph then you need to work on the launch or the driver.

I would not look at sinking more money into the existing heads if you should find they are lacking. Money wise it would be better to sell them off and start over. If you re-port them then all the money sunk into them already is just thrown away but if you sell them you can recover some of it. When you look around LT4s are NOT really where it is at for max NA performance. Sure guys will note a few exceptions but given the one time popularity of them there are a LOT of them out there and few running really well.

 

^ What he said. It could be capable of 10's right now as it sits. No sense in fixing it if not broken!

 

ya thats what i figured but either way i have the money to buy the heads and cam finally so i want to buy some to increase power because when i go back to the track i hopefully will be improving driver and launch from po lol i have been racing for a couple years now and he said he only raced a few times just wondering now what would be the best heads for my motor to retain it streetable but make the most power without it being all top end again i appreciate all the replies guys

 

In that case I would either get the Ai 200cc stock castings or step it on up to the Trick Flow 23 degree 215cc Ai ported heads....those are capable of nearly 500rwhp; should do the trick pretty good

http://advancedinduction.com/LTX/AiL...ccCompHead.php

 

i agree guys but even if it is capable of tens i might as well improve on that while i have the money to spend on heads and cam it will only improve performance and i dont see how aftermarket heads wouldnt flow better than stockers even ported and a cam too match IMO

 

Not necessarily true, some aftermarket LT1 heads are crap compared to ported stockers....take Edelbrock heads for instance or even some older AFR heads get blown out of the water by 200cc Ai stock ported heads. Depends on which heads you are comparing.

 

i really like the ai 200cc ecspecially for the price but the only problem i see is i have an lt4 block heads and intake do they offer the same package and also i dont wanna send my heads in as cores when i know i could get more than that out of it and really dont wanna spend the 400 for no core

 

Forgot about the whole LT4 thing...they have LT4 215cc ported heads that are worth 20hp over the LT1 200cc. You would have to try to find some cores though if your selling yours; the LT4 heads are much less common/cheap unfortunately, probably won't be laying around a junkyard lol.....you may be better off with ported trickflows IMO and sell the LT4's unless you really want LT4 heads.

http://advancedinduction.com/LTX/AiLTxLT4CompHead.php

 

i was under the impression that i wouldnt be able to use lt1 heads on an lt4 block or with my lt4 intake is this true and do you think i could get more than 400 out of my heads if i were to send them in as a core? again i really appreciate all the help and i like those heads they flow awesome numbers

 

the only thing that will matter is the intake because of the port location. the blocks are dimensionally the same. i think all lt4 blocks were 4 bolt mains.

 

You are correct.You can put an LT4 intake and heads on a LT1 block.Those
LT4 heads you have are good enough to get you in the 10's.What's the compression on the 396.I would go with a solid roller cam.I had a 396 in my vette and it would do 11's until I put on AFR 210CC heads with 58cc chambers.It used to have Lt1 heads on it that were totally gone through,bigger valves,valve job and port work.I did several cam swaps.The last cam I had in it was a solid roller around 260 duration and .689 lift.It was a small base circle cam.My car would run around 10.7.It was an auto with 3.73.

 

Food for thought those LT4s if ported properly can make very good power. A local guy not on the forum had his lt4 heads and intake sent down to LE to be ported and with a big LE hr cam he made 460rwhp through a 9". That car is a complete animal and should run 10s but doesnt have it hooked up yet to be able to get it down the track. Yeah you might be able to sell your current LT4 heads/cam and put the money towards a set of AI or LE h/c but if you got them with the motor or just dont care they can make solid power thats all im saying.

 

ok well they already have had the port work valve job and bigger valves done i just dont know the extent of the work done to them and neither did the po i would love to stick with them and just replace the cam but i doubt that will be enough to get me into the 10s any upgrades i should be doing like i said i dont want to kill the cars drivability with a cam but i do like big cams and could i also benefit from some suspension work or is there something else i should be focusing on i am missing i know next year i will have to put a roll cage and rear end in place to keep it safe at the track and im getting a new clutch this winter also im just really set on the 10 second club and i know im so close its possible again thanks a lot guys

 

The problem is there's simply too many unknowns here. You don't know the extent of the port work, you don't know what cam is in it, and you don't know how much power it's putting down (trap speed or dyno). If you get there (like Dwayne said) and you're trapping fairly low for the mods it's time to start tearing stuff down and out and doing it your way - the right way. If you're trapping fairly high and getting decent ETs then you've got something to work with.

Your best bet is to take it back to the track and make a few passes and see where she falls.

Take it from me about the suspension. Once you have the motor done you won't get into those 10s without it. I was stuck at 11.1-11.0 with 1.58 60's for a year before I went through the suspension in my car and replaced everything. I cut .15 off my 60' (vid in sig) on the first pass and shot me into the 10s.

So go get in the car and take it to the track. Go. Ok, go.

 

Ok thanks all I'll take it to the track and get it dynoes and do the can and clutch like planned and suspension work