G Atsma

The best thing to do with ports for your use is to get rid of "zits, warts, and hiccups".
Smooth the flow but keep velocity up.

LionPride

​​​​​​See, I was thinking that the strategic placement of structure inside the runner could restrict the flow along the surface causing standing eddies to form (like a pickup bed with the tailgate up). Placed in the right spot, it could take the place actually adding material to the runner. Done just right, you could pick up flow and velocity. Done wrong it would just be a mess.

G Atsma

Define "placement of structure"

LionPride

Cutting divots of the right size and shape in the correct location as to interact with the air/fuel mixture to form the standing eddy currents that prevents the air flowing through the runner from contacting the runner itself in that area but to flow smoothly over the eddy current(s) allowing you to reshape or reduce the effective runner size by the removal of relatively small amounts material.

Think underwater rocks in a rapid or empty pickup bed.

G Atsma

I would give a call to Tony Mamo to see what he thinks about your port ideas.
I can pretty much gaurantee he has come across similar ideas in his past with heads.

MuhThugga

Even better. More bore always helps.

In regards to making the ports smaller, you could fill the floors with epoxy and then reshape the ports.

G Atsma

Which cam are you going to use, since the port arrangement is the opposite of that of Gen III/IV?

LionPride

This one that dropped a couple month ago.
https://briantooleyracing.com/btr-lt...s-engines.html

Before that you needed a custom cam, not worth messing with.

LionPride

Someone with skills could...

LCBE

I think its a great project, unusual, adds interest to the project. Keep us updated.

headsup9550

I'm not trying to start an argument, but I'd say the OP is trying to do his research! Hotrodding is not sitting around reading about which Bolt-In parts showed less hp on this or that dyno, the guys who make HP get their hands dirty which is also why nobody would concern themselves with something like headers being expensive. Somebody buying headers for a project like this probably doesn't have what a guy needs to try certain things until he gets the result he's looking for. Of course this would be rectified in 10-15 minutes with a flange swap on whichever LS headers a guy already has.
I think this is a very promising endeavor, especially if this person will be planning boost after he gets the mechanical side straightened out! I'm excited about a couple of these retrofits going on right now and I've been out of work for a while, starting a new gig today. As soon as I recover from being out of work in a couple of months, I'm gonna round up the stuff to do my own with a little different combo..

Che70velle

iTrader: (6)

Hope the best for you here. Post some results when you get it sorted out.

LCBE

50Xhp, Easily makes power at 7500 rpm.

Milled and ported 706 heads can get there with a larger but similar cam. I'll stick with my gen3/4 for now.

Davidsk

Regarding the ICT (I assume you mean "Individual Coil Technology") direct injection blockoff, that can be a good move if you're switching to a different induction setup. LS intake adapters might be needed to make everything fit together seamlessly. You can also read this guide.

LS headers might fit, but it depends on the specific headers and your engine setup. Sometimes, slight modifications or adjustments are necessary for everything to work together.

lt1z350

we now have multiple stock ported lt4 blower combos in the low 1000whp range. Lt engine builds done right destroy common ls builds. Look how hard some struggle to make 550whp on a ls n/a build. Hell some blower cars can’t reach that with out heads and cam. Poke a cam in a cameo ss with a msd manifold and headers on e70 it easily makes 560whp. I tune tons of btr 225 cammed combos and 560 comes easy on them. Key is using the direct injection when tuned correctly it’s worth 60 hp btr already proved this over port injection.
i was gonna ls swap my 4.3 boat and decided to a 5.3 lt as even stock heads and cam it will perform way better way more efficient then a carb and or port injection ls combo.
my 2017 zl1 with LME ported stock heads a very small cam on sbe with a ported stock blower made 970whp and now with a 2300 maggie on it as got it for 2k is making 1050. It’s the whole package and tons of lt swaps now happening taking advantage of the direct injection. Key is knowing how to tune the di correctly as I do.

as for this thread Richard did the swap and I do believe it was 100 hp gain with using the hybrid cam they had to grind and slight compression bump. So stock for stock seems like a really good gain on hp to do this head swap on an ls when comparing a 799 head to a 5.3 lt truck head. But as I said I’d keep the di and gain all the benefits of it.

02redchevy

Maybe on a smaller bore, yes the LTx head style is better, but bigger than 4" bore.. the LS3 heads are superior flow wise compared to an LTx head.
Can you actually show me proof that direct injection adds 60hp? I can almost guarantee that's not the case.

Why are you also comparing a "done right" LT build to a "common" LS build? Let's compare both that are "done right" and you'll see there really isn't much of a difference, with the edge going to the LS in that case.

Scarebird

Article a few years back comparing L83 and LM7

02redchevy

Yeah the l84 blows the lm7 out of the water. I agree on a smaller 5.7/5.3 bore, the LTx heads blow them out of the water.. when you get to rec port heads.. that whole game changes.

Scarebird

This is what my L84 heads looked like...



That being said the DI does inhibit flow a bit - not enough to really make a difference to me.

LionPride

Data for the graphs taken from relevant Richard Holdener videos to the best of my ability. It was the closest comparison
I could find. The shortbock for both is a 5.3 with flattops.

The LS is Summit Pro LS Stage 4 cam, Katech ported 706 heads, and truck manifold.

The Hybrid is the BTR swap cam, stock L83 head and L86 truck manifold converted to port injection.

Looks like pretty comparable. So long as you aren't looking to power a full featured street car, it looks like an option for a low investment small bore build.