I've been wanting to build a 383 ramjet with the fastburn heads and drop it into my 2003 chevrolet silverado 5.3 liter z-71 for a while now. What all would I need to do to complete the swap or is it even possible? I know how to build the engine and that engine mounts will probably need to be changed. But how would I go about knowing what to do with the wiring harness and working all the computer problems out. If anybody has ever tried this, any information would be more than helpful. Thanks!

 

I am sure that it would be possible if you really wanted to do all of that work, but there is no point. You can get more power out of that 5.3 with more reliability and less $$. You might want to talk to madman about making you some custom motor mounts if you want to don't want to make them.

You night have to do a stand-alone if you go the ram-jet route, but I am not sure. Good luck if you decide to do it for sure.

 

The main thing I wanted with the ram jet was the low end torque for the 4x4 application. Sooner or later I'll be putting a six inch suspension lift and running 35" tires. The only mods up to date or a TCI shift kit, aem brute force induction, descreened maf, and a flowmaster muscle truck exhaust. I have absolutely no bottom end hardly. Any suggestions are welcomed

 

Low end grunt/torque = Whipple or Radix. You could get a non-intercooled Whipple for about $3500 and a Radix for about $4500, +/-. Each of these would give you about 100HP each, much of it at the low end.

 

If you are interested I have Ram Jet manifold and all the parts to go with it for sell. PM me if you want to know more.

 

Man with all the cash it would take you to do the swap it really wouldn't be worth it. If you want low end grunt just swap in a radix'd 6.0 or a 408 iron block stroker. You'll be much happier with either of those over the 383 ramjet. That's what I have planned for my 72 Blazer and it's being built for offroading.

 

To build a 408 with the radix, how much money are we talking about? I have a 350 that I can stroke and build from there. I'm still fresh out of college and funds are low. But I gonna have a heap big fun project come christmast time

 

Well I'm no expert but I don't think a radix will feed a 408 but I'd bet if you put a radix on your 5.3 you'd probably be right around where you'd be with that 383 ramjet plus you'd probably be getting better mileage and like stated earlier that would be around $4500. If that wasn't enough you could swap in a 6.0 and keep the radix and that would definitely be more than that ramjet setup and you'd basically just add another $1,000-2,000 depending on what you could find a short block for.

Look at it this way.
your stock block - $0
machine work - $500-1,500
383 rotating assembly - $600-1,000
Ramjet system - unless found used $3,000
Fastburn heads - $600
and that doesn't include all the little odds and ends. Even if you did do all of that I think you'd be around 450 to 500 horses and the torque curve wouldn't be much better than what you have. Not to mention it will be impossible to smog (if you have to deal with that in your area).
Just my .02

 

A stock LQ4 6.0L and a cam will put out way more power then a Gen I 383. All the dyno numbers you read in magazines are misleading, those numbers are gross numbers. Chevy High performance did an intake test on a stock ls1 rated at 320hp and 330lb-ft, with the stock intake it was putting out 419hp at 5800 and 416 lb-ft at 4700 gross, no accessories at all, long tube headers, stock PCM with rev limit changed .