This is kind of a multi length 2 car question... but I just scored a set of Lloyd Elliot ported 220cc lt4 heads and port matched intake. I plan on installing these on a stock lt4 block 96 corvette with 54k miles. I am looking at the comp cams xfi280 cam or an equivalent on the market. I have a set of scorpion 1.7:1 roller rockers so the lift range of the cams I'm looking at will be around .601 To .615 Lift in the 230 duration range. I have exotic muscle headers, corsa exhaust, meziere HD electric water pump, a slew of small mods that escape me... and the car has an lt4 hot cam in it as we speak. I am also planning on taking the lt4 heads, intake and cam off my vette and installing them on a 97 camaro ss. So here's the questions...

1. can I run that large of a cam with stock fuel injectors or will I need bigger ones? If I need more flow, what pound per hour and brands recommended?

2. Will I need new pushrods and lifters?

3. How do I find a double roller chain That will fit an lt4? Is it just a SBC chain?

4. I've seen several "can only" threads and you tube videos with the xfi can so if one is to believe that an lt1 owner can stab this stick in their car with no other mods done, how much of what I'm asking is necessary versus luxury to get the most out of the performance?

5. Will the camaro need any further mods to make the lt4 hot cam and drive train work? And is it beneficial to me to lightly port the heads there before install?

 

You need larger injectors when the flywheel HP goes over 360HP. Obviously the LE LT4 heads with the XFI cam will be closer to 500HP at the flywheel. Why not let Lloyd spec the cam. To estimate minimum injector size, multiply flywheel HP X 0.07. Example: 500 X 0.07 = 35 #/HR

 

I bought the heads from someone who paid to have them ported but never installed them. Got a hell of a deal too... but I was trying to do this on a budget since I'm trying to do both cars. I never put consideration in calling them but I appreciate the tip

 

1. Yep. At minimum I'd run the FAST 37# matched set that Racetronix sells. A 42# injector would give you a little more wiggle room though.

2. Depends on how your lifters look. Considering the LS7 lifters are $140 it's not exactly an expensive option to replace them. Pushrods will need to be measured and sized to fit and you're likely going to need hardened pushrods and guide plates for the new rockers.

3. A Cloyes double roller for the 87+ Gen 1 small blocks will fit but you will either have to clearance the stock timing cover or you will need a TPIS billet timing cover (not cheap, trust me).

4. Not entirely sure what you're asking. You'll need larger injectors to fuel the engine and a computer tune to make it all work or you're going to have one expensive piece of lawn art.

5. If you have the heads out it wouldn't hurt to have a valve job done to them. New springs wouldn't be a bad idea if the set on the heads is old or has a lot of miles. Porting them shouldn't hurt anything. Keep in mind you'll probably need to use the LT1 intake on those 220 heads unless they have raised ports. You'll certainly need to use the LT4 intake on the LT4 heads. The Camaro will also need a retune.

 

I keep finding post of people running larger than the lt4 hot cam claiming can only. They don't mention tunes, headers, or any other mods... which doesn't make sense to me. I know a bigger can should at least mean headers and larger throttle body, so I guess what I'm asking is should I wait to install until I have the right lifters, pushrods, throttle body and injectors? Or is that stuff I can add too later and install now to enjoy the car?

Also I have an MDS digital 6 ignition box I haven't installed yet. Is that necessary or a waste? I have an MDS opti and wires already running to e3 plugs.

 

"Cam only" usually means the heads are stock with the appropriate springs. Generally you don't do heads/cam setups until you've done all the other mods such as headers, exhaust, CAI, etc...

You don't need a larger throttle body for a NA street car. The 48mm is more than enough.

 

And you don't need an ignition box if you don't have a power adder (nitrous, forced induction).

A tune is essential. You can gain 10-15HP with a tune on a totally stock engine. Why would someone not want to gain that, plus set the tune to run correctly for a new cam?

 

Not to mention you run a good chance of washing the bores with fuel if you try to run 40lb injectors on a stock tune.

 

I think he was asking about/indicating that people who did "cam only" (for example his LT4 cam in his stock 97 SS) didn't mention that they got a tune. At least that is what I was responding to.