I'm building a Gen III 5.3 with a LSA S/C and I be buying a BTR PDS Stage 3 cam(231/248 .617"/.595", 120+5). I have set of 317 heads sitting around that I want to use but I want to get them surfaced .030 to compensate for the lower compression. Will this work ? I don't want to have any PTV issues.

 

You'll have plenty of room with 317 heads. It depends on what 5.3 you have, you may want more compression. If it's a dish piston 5.3, you may want to calculate your compression. A car I tune on has that cam in a Gen IV LC9 with the 10.0:1 compression I think they have, and it runs good. I don't remember what it had for clearance.

 

That’s a big cam for such a small engine

 

Yup. That's even a pretty hefty cam for a bigger LS engine too. Something like a 222/236 116+2 would drive nice, make a little cam music, and make good power top to bottom. Blower size is the limiting factor on an LSA build. An overly large camshaft doesn't really help things....just kills a lot of low end power. It would make a little more on top for sure.

I have an L33 (5.3L aluminum block) that I ran for a while with a TVS2300 on top. Ported and lightly milled 243 heads and a 218/230 118 +2 camshaft. It is in a Chevy half ton pickup that works for a living. You didn't mention what vehicle this was going in. For a heavy ride, go with a milder cam. Light, you can get away with a little bigger.

 

It's actually a Gen3 4.8 that I'm swapping the crank for a 3.622(because I have new one sitting). I will also install some Gen4 rods too !

Thanks for the advice I just might do a stage 2 instead(227/242 .614"/.592" 122+6). I'm wanting high 500whp to mid 600whp.

This engine is in my 1974 Datsun 260z.

 

My last two LS3's had TVS2300's on top. First one was a jackshaft Magnuson blower with a 3.3" drive pulley. Rear pulleys were in a 1:1 ratio. With a 219/231 115 cam and all of the bolt ons, it made 640 at the wheels. Boost was 8.5psi. Second one was a Magnuson Heartbeat with a 3.2" drive pulley. With a 224/234 116+2 cam and all the bolt ons, that one made 660+ rwhp. Boost was 9.5 psi. Both of these had really good power down low even out of boost. You could accelerate briskly without ever seeing boost if that's what you wanted. A little more right foot pressure and you're at full boost instantly.

Some will tell you that a cam like you're considering would be of benefit because it would kill some low end (uncontrollable) power that you can't use in a light car. That's bullshit. You control the power with your right foot. Apply as necessary. MUCH better to have it and maybe not use it, than to need it and not have it.

I don't know where you want to start drive pulley wise, but it will probably take a 2.5"ish pulley to get you over 600. That's with a manual trans. With an auto trans, it will take smaller than that. That's assuming a stock diameter crank pulley. And don't be scared of a 10.5 static CR. Running a lower CR is just giving away power.

A flex fuel setup makes producing good power much easier.

 

Sorry I missed this, but you need square port heads to match up to the LSA's supercharger manifold. There may be adaptors available to match the blower to the catty port heads. Not sure if any square port heads will bolt on without valve interference due to the 5.3L's small bore.

 

So the car I was referring to has had a LSA blower on a Gen IV LC9, and a LS1. He changed the cam from a smaller btr blower cam to this one. Now he did change the converter to a little bit looser, but I don't have good data on that yet, however the car did 60' faster with this bigger cam. It went from a low 1.5 to a mid 1.4. He strictly changed to a bigger camshaft because he hated how the smaller camshaft sounded.

 

Were you running meth injection with those LS3s with 8-9.5 psi or was it not needed?

 

I did try meth on the later one. I think it added 15 or 20 hp. Meth really isn't a good fit for a TVS blower. Injected before the blower, it does very little for intake air temps. Centrifugal and turbo setups are where meth really adds to the package. With a TVS blower, there's really not a good way to protect the engine if the meth system goes **** up.

If I ever build another TVS supercharged setup, it will be flex fuel ready from the get go. 750 at the wheels is very doable with a Heartbeat TVS running on E.

 

Unfortunately theres no e85 around here. Gonna run a tvs2650 on a LS3 with stock pulleys. So you're basically saying meth injection may not be worth it?

 

To take advantage of the 2650's air flow capabilities, you're for sure going to need more octane. Especially stuffing all that into 376 cubes worth of displacement. Might not need it as bad if you stroke that LS3 out to 416 cubes. Other ways to lower boost are really good cylinder heads, the biggest long tube headers that will fit, and a big hairy blower cam. The 2650 is supposed to have an excellent intercooler system, so IAT's should stay in check even at higher boost levels. Outside of E85, a meth system is probably the easiest was to add octane. You'll get little cooling effect unless you figure out a way to inject it downstream of the blower.

Here's a pretty good discussion on higher octane options. looking for some opinions on upping compression/buying barrels of "race gas" - Page 2 - LS1TECH - Camaro and Firebird Forum Discussion

 

If you haven't already bought a cam, I'd suggest going with the Summit Ghost Cam 8715.

 

OP,

We like @ryeguy2006a cam recommendation if you haven't already got one. The SUM-8715R1 Ghost cam would be a great fit for this LSA supercharged 5.3 in your Datsun. Specs on it are .600/.575, 222/234, 115+3 with -2* of overlap. This cam right here has been very popular in a wide variety of combos. Big thanks to @Mavn for helping us coin it the "Ghost" cam. It will have a smooth to noticeable lope depending on the idle speed. It will be smooth and stealthy but packs a punch when you lay into it. It will be happy out to 6,800+ with our .600" lift beehives. If you have an auto trans you can get away with a stock converter. However, we recommend a 2,500+ converter.

 

So some things have changed and now I'm trying to decide which block to use. I have a aluminum 5.7 LS1 block ready to build and a Gen III iron block 5.3 that needs a cam bearing. I'm leaning towards the 5.7 but I know the 5.3 is better for boost(I have a LSA Supercharger). I'm not trying to make a huge amount of whp, anything in the high 500whp to 6xx whp is good for me. I want to put forged pistons and rods in the 5.7. I am on a budget so I'm trying to figure out the most cost efficient way to have a strong bottom end in it. I know with the 5.3 I can use gen 4 internals and be good.

I am considering going with a different cam. I plan on either 799 or 243 heads, LS7 lifters, and a better oil pump(melling 10296 maybe), reinforced brick. I currently have a brand new set of btr .660 dual springs and 7.4 hardened pushrods, LS3 oil pan, FIC 850 on Aeroflow rails, griptec 2.45 pulley(already installed), 6 gal water tank, Afco CTS-V heat exchanger.

 

Ls1 block can take the boost you want no problem. I would go that over the 5.3.

 

I totally disagree and would use the 5.3. The LS1 will support a LSA with 8-10#, but if you want to start turning things up, it's just a time bomb. The LS1's, boosted, just don't have a great track record. They have the weaker rods, and internally, they just don't have the support.
If your strictly looking at 8#, go for the LS1. Once you start hitting 600, your living on the edge of it though. JMHO

 

If I go with the ls1, I was planning forged pistons and rods but they come at a cost of course. I’m pretty sure I can use Gen 4 pistons and rods and have no problem with the 8-10 boost level just at a lower cost but It’ll be heavier and I have to replace a cam bearing.

I might end up with the 5.3 because of the cost. I can get pistons and rods and a set of 799 heads for less than the cost of forged LS1 rods and pistons.

 

Im not sure a 5.3 will get you your HP goals. I know on a 5.7 it takes around 14-15 psi to get ~600whp, thats with a maggie 2300.

 

So I'll tell you from experience that 600 whp in a light car is a lot for the street. The LSA boost comes in hard at low rpm's, and will make more than enough power for your Datson. I wouldn't overthink it. Guys are making big numbers with iron block 5.3's and stock Gen4 internals. Put cam bearings, your choice of cam and run it. My Camaro could only fit a 275 rear tire under it and I could spin the tires at just about any speed. Scary the first time that happened at highway speeds. I sold the car before I could try a slick, but that's probably the only tires that would have given me enough grip to get a real launch.