nico z28

any thoughts?

Fastbird93

Here's a thought. Save your money and get a LE or AI head/cam package. Make more power for less $$$$$$$$$.

nico z28

how much hp,, and $$$$$$$$$$

n2ceptor

http://web.camaross.com/forums/showthread.php?t=302630

Z95m6

Ditto. The LT4 heads don't flow all that much better than LT1 heads when they are both stock. The LT4s just have more potential for porting. Maybe i'm over simplifying but buying the LT4 kit is like replacing your stock heads and intake with another set of stock heads, and intake then adding a hotcam.

LT4Firehawk

The LT4 heads do flow a good bit better than LT1 heads. This can be shown by my car which is putting down 311RWHP. Basically the only real differences between mine and a stock LT1 car and are:
ram air intake
cat back
extrude honed exhaust manifolds
LT4 engine (NOT hotcam, but rather stock LT4 cam, which is about the same or a little smaller than an LT1 cam)

Considering that the real differerence in the LT4 are the heads, you can see that their is a pretty nice gain.

Now, having said all that, I would also recommned you get a LE or AI head/cam package. Cost will be the same or less than an LT4 kit, and you'll make more power. The only reasons to go with the LT4 kit, is if you just really want something that is factory proven and stealthy (until you pop the hood). An LT4 kit with a good tune will barely sound any different from stock.

Antz97ZNJ

Like others have said theres more bang for the buck options out there

Z95m6

Don't LT4's come with 1.6 RR's. I thought thats why they originally came with LT4 Km's. If so there is some more Rear wheel hp. I thought i've seen flows sheets of LT4 heads only flowing like 10-15cfms more than a stock LT1 head which really isn't that big of a deal.

LT4Firehawk

Yes, the LT4 comes with 1.6RRs, but that still doesn't account for all the HP difference. My 95 Formula with K&N FIPK, cat back, no cat, 214/214 cam, 1.6RRs and ECM tune only put down 285RWHP, and would run a best of 13.6@104 in the 1/4 mile. With just the FIPK and cat back, it put down 258RWHP and ran 13.9@101. The LT4 Hawk by comparison, puts down 311RWHP and runs 13.3@107.

I don't doubt that you may have seen flow sheets with that small of a difference, but were both sheets done on bone stock heads on the exact same flow bench utilizing the exact same procedures?

aaron_depue

I though the hot cam kit (heads,intake, cam,ect...) was suppose to make about 400+ hp? Anybody know about how many rwhp that a LT4 w/ hot cam kit will make? I really want to do a LT4 hot cam conversion to my LT1 but I still have a few questions, so figured that I would run it by you guys first. Willl LT1 headers fit on LKT4 heads, both are non ported?

LT4Firehawk

With the proper bolt-ons and good ECM tuning, you can make 400HP with the LT4 kit (w/hotcam). But this is going to include long tube headers, air intake, cat back, throttle body, and probably no cats too.

Here's a rough breakdown of common HP figures with various LT4 configs:
LT4 (stock in Vette, or w/ intake, catback and ECM tuning in f-body): 300RWHP
LT4 w/ hotcam: 330RWHP
LT4 w/ hotcam and all bolt-ons: 350RWHP

All these figures are with an M6, so figure a 15% driveline loss and you get roughly 411HP with everything. Again, the LT4 kit is a nice kit for someone who wants a reliable factory designed setup, but you can make more power for the same or less money with a custom cam/head package.

aaron_depue

I like the factory typpe relieblity. Its my daily driver. You seem to know your stuff. What cuputer/fuel mods(if any) will need to be made. I need to know becasue I will make an order soon. that reminds me where a good spot to purchase the LT4 stuff

CColtManM

I am actually doing a similar mod to this right now! It going to cost you around 1,000. And that is minimul when you have to replace everything. I am NOT replacing everything, just gaskets, timing chain, (i should do oil pump), but i am also doing headers, which is a big plus, longtubes.

If you are doing the project yourself, gooood luck. Make sure you have someone with you that knows that engine inside and out. You will tear everything off of your car under your hood and leave just the block in the end. Thats why if you do this, spend the extra 200 bucks and rebuild the engine. I wish i did. If you have a shop do it, they will chage you a min. of 1200 bucks. Max is 3k if you don't have all the parts when you bring it to him.

Just don't go looking for the cheapest things, thats what i did, but hey, i'm cheap.

LT4Firehawk

Any good tuner can do the ECM for you, personally I used madwolf (www.madz28.com) and am very happy with the results. As for fuel, you should be fine with the stock injectors even if you do long tubes along with the kit. You shouldn't need to completely rebuild the engine when you do the kit, but I would go ahead and do all the valvetrain parts that aren't included with the kit, and also do a good timing chain (peak HP on the LT4 kit is going to be around 6K rpm or a little more with long tubes). Also, since you'll have to remove it for the cam change, it would be a perfect time to replace the opti and waterpump.

aaron_depue

I have heard about the opti. What is the big deal with it. Some people hate it and want to switch it out. I have no idea what opti is.