Still pretty new to the scene as I have only had my 97 Camaro for 2 years now. I am thinking of doing the most basic of bolt ons, I/H/E and the such. The current setup in the car is an LT1 with an LT4 headswap (done before I purchased the vehicle) ((supposedly)).

1. With the LT4 heads, is there any breather upgrades i.e. stealth ram, basic cold air, ect. that would work well with this current motor setup?

2. Bigger Injectors/Fuel pump/ others, will i need them and at what point?

3. Target is 400 +/- 10whp.

4. Cam, I would prefer a mild street cam. what should I be looking at doing along with the cam? valve spring upgrade ect.?

5. Dyno/Street tune I know it'll be necessary and I am NOT doing all of the mods at once, considering I have a very stringent budget (low budget, mostly tax money each year).

6. Porting the head. I know that LT4 heads are considered a pretty substantial upgrade already. Will it be necessary to port them to make the power that I want?

7. Pistons, Rods, Connectors. I'm pretty sure the block is nearly bulletproof, but what should I be doing about the moving assembly down low?

I would appreciate any and all input from people who have done any kind of work on an LT4 swapped LT1. Thank you for your time and experience.

 

Does it have an LT4 intake manifold? Factory LT4 intake is powder coated red.

What transmission? That will affect how much flywheel HP you will have to make to achieve 400 HP at the rear wheels.

Check head casting # against this documentation:

https://www.grandsportregistry.com/lt1vslt4.htm

Casting number is under the rocker cover,

The LT4 heads flow about 13% better, according to above reference. On the Corvette the LT4 (complete package) made 30 additional HP if you accept factory ratings. I run ported LT4 heads with ported LT4 intake on a 381ci, with a fairly mild cam, made 490 at the flywheel, 425 HP at the rear wheels, through a T56. The cam was selected to meet tailpipe emissions.

 

Intake is powdercoated red. I believe it has the Tremec (not sure if its BW or Tremec on a 97, but stock T56)
I plan on keeping the vehicle a 350 and was considering the Kooks Longtube true dual 2.5s with an X pipe (3" a possibility with some engineering) and cat delete back to the mufflers (thinking borlas for the beautiful, rich tone).
In the state of NC, my vehicle is now old enough to bypass emissions testing.
If I have to run a slightly larger cam, I will, but I really don't want every cop from here to Florida pulling me for exhaust note LOL.
I should also mention that currently, I have a higher flowing K and N air filter into the stock box, new NGK wires, Iridium plugs (already forgot brand), brand spanking new Opti kit and water pump (since, you know, LT1 camaro) and while I was at it, even a new harmonic balancer.
I was also wondering if there was anything I could install on the intake side of things to make that motor inhale much more cool air.
I will be attaching pics of what's under the hood probably tomorrow during lunch break.

 

I would start with verifying the casting numbers from the page Fred referenced. If what you have is LT4 (not LT1 with a painted intake) then you have a great base to work with.

I would call Lloyd Elliot http://elliottsportworks.com/ and discuss your goals. The LE2 package with a cam and porting your intake will easily take you to your goals.

Kooks is a really nice exhaust but is pricey. I wouldn’t personally look at the 2.5” exhaust, go straight for the 3”. If you have a shop close that can weld stainless, Speed Engineering sells the same system for the LS1 for $500. I have this on my car and only needed minor mods to make it work. In my opinion, both systems need to have a couple of the joint welded after fitting in the car, and the headers and remaining joints v-banded. I had to install the pan hard relocation bracket, trim 1.25” off the passenger side, and add 3” to the driver side. I am running Kooks long tubes.

 

The T56 was still made by BW, but right about 1997 BW sold the design/production line to Tremec and Tremec move production to Mexico - still the same transmission. With the manual trans you will need to make about 460 HP at the flywheel, to make 400 HP at the rear wheels. That will require porting the LT4 heads and intake. The LT4 intake has room for taller ports to match the LT4 head ports, but GM ran out of money (and were committed to the changeover to the LS1) and never completed the revisions to the intake manifold. The internal runners are basically the same as the LT1, and do not match the LT4 head ports. There is no need for an aftermarket intake manifold.

You will need a good cold air intake kit - K&N, Moroso, etc. Alternatively, look into adapting an LS1 airbox and lid.

Kooks headers are very good, but expensive. A lot of people opt for the Pacesetter long tubes to save a buck. But if you can afford the Kooks, good choice. You definitely want a full 3" exhaust after the Y-pipe, and may want to consider the Mufflex 3.5" catback. Using a catback eliminates the possibility of the X-pipe. {Personally, I'm not sure what the X-pipe is worth. I have never seen a definitive test of the potential gains.) I run a Borla XR-1 bolted to each collector, and a 3" pipe on each side, straight back, with a turndown in front of the rear axle. I ran a 4" Mufflex catback for a while, but that would be overkill for 460 HP.

You will need a beefier cam. The exhaust can be selected to tame the noise. The cam has to be selected based on the head porting, and your requirements for drivability. As noted in the post above, look at the Lloyd Elliott website for cam info.

You will need at least a 52mm throttle body, and 32 to 36 #/HR injectors (I would recommend 36 #/HR). Throw in a good tune - getting harder and harder to fins for the LT! - but we can steer you i the correct direction. Many tuners will do the initial tune, and then offer reduced cost for future upgrades. But virtually any change you make will require an update of the tune, to realize full benefits of the change..

The stock rotating assembly - crank, rods, pistons) is OK with 460 HP at the flywheel, as long as you aren't looking at turning 7,0000 RPM (which isn't necessary). That assumes everything is still in decent condition. Otherwise, it will need to be freshened up.