Beard

Hi, first post......need a little direction.

I am fairly new to what is interchangeable on the LS motors since this will be my first LS build.

I am looking to build an engine to go into my RX7 FC chassis. I already have the LS mount kit and a T56 trans that I have went through and installed mew bearings, the update kit and upgraded syncros. It is ready or a nice stout engine.

My goal power without any adders is around 500-525whp or more on 93 octane. It seems like a reasonable goal and a reliable one if I use good components.

I am willing to do rods/pistons and I have access to a machine shop to modify anything I want.

Should I start with a LS1 longblock or go with the LS2?
What intake should I use?
I already have Hinson Performance mid length 1-3/4" primary headers (3" collector)

Basically, I need some solid, proven, ideas on what direction I should go.

garygnu

ls2 + l92 heads + fast 102mm intake + EPS cam.

BlackScreaminMachine

iTrader: (17)

If you find yourself even a LS3 Short Block, that would work as well. Give you a larger bore.

Beard

Okay, with the FAST intake, what throttle body should I use? Can I just get a LS2 and use all of the sensors and components with the L92 heads? I will need alternator brackets, alt, P/S, A/C...etc. Or do I have to get the truck brackets to make it all work together?

Do you think it would be necessary to do much more to the heads than to port match and polish? Is there even much to port out on the L92 heads or are they best left in stockish form? With the EPS cam and L92 heads, will I have to clearance the pistons? Would it be even necessary to upgrade the bottom end more than upgrading rod bolts, bearings and maybe a balance?

Beard

Also, would it be beneficial to upgrade to Ti valves (better springs and pushrods will be used) so it can rev a little higher or is 6-6,500rpm sufficient? Or can I even use the LS3 hollow valves on the L92 heads?

AES Racing

iTrader: (6)

I'd stick with factory LS3 intake, results from the FAST on smaller engines haven't been outstanding.

Yes, LS3 valves will fit L92 heads, you can also just get LS3 heads complete.

I wouldn't worry about Ti valves, they need a fair bit of attention to installing, rocker arms, lash caps or hardend tip. Hardend tips fall off eventually.

SOMbitch

iTrader: (8)

There are many ways to get 500rwhp with LS engines but it is tough on a LS1. Assuming a FAST (do a VIC if it will fit) an LS2 or LS3 will be much easier. The plastic IM used on these cars can cost 40+ hp easy on some high reving setups vs a Vic/Super Vic.. Run as much cubes as you can and while the sqare port heads are a great bang for the buck if you see the right Cathedrals in the classifieds they can be as good or maybe better....

Beard

Well I will probably be going with the LS2 bottom end due to pricing. I have plenty of coin to spend on the rest of the car and honestly, I don't really NEED the extra .2l. With that said, I am pretty much set on a LS2 bottom end with L92/LS3 heads. I will probably be going with a forged bottom end (can be had for a reasonable price) and a good set of springs/upgrade the pushrods. Obviously a good mid to high lift cam to boot.

So now I am getting mixed reviews on intakes. Which intake should I use? LS3, FAST 90mm, FAST 102mm, Victor, etc? Will the LS6 intake fit?

This arises another question. What should I use for tuning? Hinson Performance offers a reflash of the stock computer to my specs, cut immobilizer etc. Would that be suffice or is there a good programmer out there that I can do it myself and then pay my tuner to tune it for me on the dyno?

garygnu

you could do a ls1 383 ci,it will make 500 hp/tq with good heads and valve train.I have seen ls3 crate engines for $6300.

Beard

Thing is man, I don't want to have a stroker/overbored engine. This will be used in a RX7 that will see higher RPM at long periods of time as I plan on putting it through quite a few HPDE's I don't want to rev it to the moon but I want it to be able to handle 7500 without a problem or higher. I don't expect it to make power there, but I would like it to stay together if such an event arises.

I think I could build a LS2 with a forged bottom end and L92/LS3 heads for much less than $6300. Hell Texas Speed sells a fully built and blueprinted bottom end for $4100 ( http://cgi.ebay.com/ebaymotors/TSP-4...mZ300214572323 ) and all I would need is accessories and a top end which can be had for under $2200. I don't think the LS3 is for me, although it would be nice.

I want to build something to last and well, be pretty much overkill. So it can handle anything I throw at it and last as many miles as I need it to without any worries.

You have to remember something, 300hp/300ft-lb will make an RX7 FC FLY! So with 500+, it will be a screamer. To top it off, this chassis is fortified to the max with some seam welding and cage. It will have grooved R compounds and the attention to detail this car will have when I am done will make some exotics look mediocre.