Hey everyone, Im looking for some real numbers from anyone who's running a 4.8/5.3 with an Lsa blower. I've searched around but most guys are running them on 4x4 trucks through an auto so I really can't get a good idea on what to expect. First off, heres my current setup:

2001 5.3 Lm7, stock bottom end
799 heads milled .030, unported.
Tick performance stage 2 turbo cam, 219/223 .617"/.595" LSA114+3.
Walbro 255 fuel pump
Fast 102 intake and ebay 102 throttle body
1 3/4 inch long tube headers to a single slp loudmouth
LS9 headgaskets and arp head studs
Comp hardened push rods and rocker trunion upgrade
Brian tooley racing valve springs
Mcleod twin disk clutch
Stock T-56 trans

Car put down 350hp, 350tq on a mustang dyno.

Thats pretty much everything. Fuel system will obviously be upgraded, Im leaning towards a twin walbro 255 setup with either a -8an or -10an feed to an adjustable regulator.

I put the motor together with intentions of going with 61mm twins, but Im running A/C and have no intention of getting rid of it, so cost wise and ease, the lsa blower seems to be the way to go for me. Also i know i will have to pick up adapter plates for the blower, i have no problem with that.

Now for the blower.. So my plan is to pickup a stock Lsa blower off a zl1. I will run the stock upper pulley and run a corvette accessory drive with an aftermarket 10.0 crank pulley, which i believe should give me 14 pounds of boost, Im also going to run meth injection.

So my goal out of all of this would be 600-650rwhp. Current tune is on 93 pump gas. So do any of you guys think this is attainable with my little 5.3? I keep jumping back and forth between twins and the blower, but If i can achieve my power goals with the blower I really want to go that route. The car is mostly street driven, occasional weekend strip.

Would appreciate any input, thanks in advance 🙂.

 

Also forgot to mention, Ill be running Siemens deka 80lb injectors.

 

What is your current compression ratio? Your heads and exhaust will be the limiting factor in my opinion. I really have no idea what it will make, I'm running a LSA supercharger/LS9 cam on a LY6 on e85 (10lbs of boost)but haven't put it on a dyno.

 

I have 799 heads, which are basically ls2 or 243 heads. Compression should be around 9.6:1

 

Keep in mind that the ZL1 made the numbers it did with much better flowing heads, You're still going to make good power. Do you have easy access to E85? It would be a better choice of fuel and since you still have to build a fuel system you could build it to be compatible.

 

No e85 really near me. Closest is about an hour drive 😩. I would probably already be running on it if there was a station near me.

 

Ive been looking at different heads. Texas Speed Prc lq9 2.5 heads seem like a good choice and a resonable price. Do you think a set of heads paired with larger 1 7/8 longtubes will be worth it and net me the power Im aiming for?

I saw a video on youtube with a guy who has a stripped down c5 that made almost 700 at the wheels with an lsa blower on the ls1. He also ran those texas speed heads, and their cam.

Might be easier to talk 1/4 mile instead of hp. I would love to get into the mid 10's with the blower setup on drag radials. Car currently weighs 3590 with me in it, not sure how much weight the whole setup will add.

 

Yeah, have Texas Speed do your heads, that plus long tubes WILL net you more power, especially with the blower.

 

Great, sounds good. Ill probably end up swapping out the heads and putting on a set of 1 7/8's.

 

You could have YOUR heads done for less $$$ and end up with the same result. TSP will do that.

 

Only thing Ive had mine milled to bring compression back up. Wouldnt I be better with the stock lq9 heads that will drop compression?

Edit: Also i have a friend that would buy mine current heads for his 5.3, so I wouldnt mind just buying a new set, plus the drop in compression.

 

Yeah, in that case then the case for a new set of heads IS warranted! Good call!

 

You don't need to drop your compression any lower. 9.6:1 is fine.

 

Ok, thats what I thought. Plus Im running 93 and with the meth injection I shouldnt have a problem.

For the heads, should I stick with the Prc 2.5 5.3 heads, or for the extra 100 bucks go with the 2.5 lq9 heads? Both heads use the same sized valves, but the lq9's flow a little better. I can get the 5.3's with the standard 61cc chamber so my compression will stay around 9.5:1. The lq9 combustion chambers are 65cc.

 

How much would your budget be for heads alone? You could also look at LS3 small bore heads and do away with the adapters and most flow really well.

 

I'm not sure the slight increase in flow is worth the compression drop you will get with the larger chambers in the LQ9 heads. I would do the 2.5 799 heads and keep the compression up a bit. I looked at TSP's flow numbers for both heads, and there is a difference, but not that much.

 

The Lq9 runs the 317 head. The stock chambers on the 317 head are ~71cc. If you're talking about shaving them down to 65cc you're basically just creating a 243/799 head with a thinner deck. You'd be better off just buying PRC 2.5 ls6 heads. I'd save the $100 and have a slightly thicker deck and slightly higher compression by getting the PRC 2.5 5.3 heads in a (stock size) 61cc chamber. Then sell yours to your friend.

 

I wasn't planning on doing heads at all, but being i decided too I really don't want to pay more than 1500.00 for a set. The whole blower setup alone is gonna cost 3500, plus the meth injection and fuel system.

 

Sounds good, this seems like the way to go. Plus I should be able to keep my pushrods being Ill be running the same head thickness as I have now. I still want to re measure though.

So it looks like I will be picking up a set of 2.5 5.3 heads, and swapping over my valve springs. Paired with a set of 1 7/8 headers Im hoping Ill reach or at least come very close to my 600rwhp goal 🙂

 

You don't need meth. You'd be better off spending the extra money on better heads like Mamo 223s (or small bore ls3s) and/or swap the cam for a custom and sell what you have. Fuel system shouldn't cost much if you're careful and look for some good deals.