Horsepower goals

[Jeff95TA]

I'd like to do some more major mods to get to around 400 hp (like to keep the stock rear vs a 12 bolt). I've considered supercharging but am leaning more towards heads/cam instead. I'm a little confused on the LT4 conversion. I've seen an article that said it puts you in the 400 range. Is this the same basic setup as in the LT4 Corvette? Wasn't that 330 hp? Can anyone shed some light on this or am I missing something?

Also, what would be a comparable aftermarket combo? What about the CNC heads - better power/$, or not the right application for me?

I'm in the initial research stage (engineers like to research first!), so any input is welcome.

Thanks!

[AndyLT1]

Are you looking for 400 rwhp or 400 at the motor? In my sig. I have my mods that gave me 340 rwhp which equates to roughly 405-410 at the motor.

Andy

[Injuneer]

Re: Horsepower goals

Originally posted by Jeff95TA
I'd like to do some more major mods to get to around 400 hp (like to keep the stock rear vs a 12 bolt). I've considered supercharging but am leaning more towards heads/cam instead.

From your other comments, I assume you are look for 400HP at the flywheel, not at the rear wheels. If that's the case, heads and cam is the way to go.

I'm a little confused on the LT4 conversion. I've seen an article that said it puts you in the 400 range. Is this the same basic setup as in the LT4 Corvette? Wasn't that 330 hp? Can anyone shed some light on this or am I missing something?

The Corvette used the "stock" LT4 cam. The published HP number is probably on the low side. The "LT4 conversion kit" includes the LT4 HOT cam..... that is where the difference in HP is. The HOT cam likes to rev, so a stall convertor and higher numerical rear gear is in order.

The claims for LT4 conversion are based on a test by MORE Performance many years ago. They got 429HP on an engine dyno. They used LT headers, a larger throttle body, and a few things they apparently "forgot" to mention, including a $3,000 aftermarket ECU. But I think the results available from the people who ohave done the conversion indicate that WITH PROPER TUNING you can exceed 400 flywheel HP with the conversion.

Also, what would be a comparable aftermarket combo? What about the CNC heads - better power/$, or not the right application for me?

There are many people who feel that you can do a very similar job with a set of ported stock heads, and one of the many aftermarket cams available. "CNC" can mean different things to different people..... CNC Cylinder Heads in Pinellas Park, FL does some decent heads.... but you are probably looking at $1,800 for their CNC port on an LT1 head. And from my personal experience with the CNC LT4 heads, they are killer in the intake side and relatively poor on the exhaust side. If you want CNC'd LT1 heads, I would strongly recommend Lingenfelter. But again, you are probably talking close to $2,000. There are a few people... the name Lloyd Elliot comes to mind.... who are doing reportedly high flowing LT1 heads for way less than that.

[N20LT4Bird]

I have the conversion. I like it. It does like the revs. I shift @ 6800 rpm on the juice. W/O the nitrous, I am running a 109 mph trap speed, so what that equates to in horsepower, I dont know??? 400 - 420 range??? I also have some other mods and the PCM was retuned by Ed Wright though.