i'm looking into getting some heads, intake manifold, and throttle body in the future. just curious to know what are you guys running for these parts. which combo seems to work the best. i'm sure there's somewhere around 50hp or tq to be picked up with theses parts. thanks... lance

 

Stage 3 5.3 heads, Fast 90mm intake, UMI 90mm tb should net you 50-60hp I would think with bumping up the CR some too.

 

Forgive me for sounding like an ***....but HOW do you have over 1200 posts and own a 12 second truck and NOT KNOW what's available for the LSx top-end ????....I'm REALLY not trying to be rude, I'm just a little confused

 

This is kind of uncharted territory for N/A 5.3 guys. No one really seems to bother with building them.

Here is what I have found:

Most prepackaged ported 5.3 heads are really meant for larger bore applications. The chambers have been opened up and valves that are too big for a 5.3 (2.02 intake for instance) are added. Porters just like to use them as cores for the smaller as cast chamber so they have more material to work with and not have to mill them a ton to regain or raise compression.

I ended up having a set custom done for me by WCCH. Richard refered to them as a Stage I head, which consisted of porting and polishing the chamber and valve bowls, a 5-angle valve job, larger valves (1.95 int/1.57ex), and milling them down .045 to a 58.8cc chamber. The intake and exhaust ports are as cast. Richard explained to me that if they stepped up to a Stage II porting program and did the ports too, that the port volume would have increased too much, killing velocity and torque.

I haven't installed them yet, but I do have pictures and flow data if you would like to see them. When I get them installed I'll be sure to get new dyno numbers. They stack up pretty well for a Stage I head, IMO. Richard was a pleasure to deal with, and the cost was more than reasonable too. The milling combined with a .045 thick Cometic gasket will bump my CR a 1/2 point.

The next mod for me is going to be a converter, probably in the 2800-3000 range. Then I could step up to a bigger cam. Cammotion recommended a 224/228 cam with these heads, but I won't go that big.

There are a few H/C 6.0 guys working on car based intake swaps. I'm sure that you realize what is involed to make one fit. mattrem working on a FAST 78 (and he has parts for a 90 test too) and Kano is doing a LS6 swap. I'm really interested to see how these turn out. Everyone says the truck intake is better in lower rpm range, but many are stalling right past that and shifting at the mid 6K range. From what I've seen, the truck intake starts to give up around 5500. Chevy High Performance did a manifold test a few years ago. I had the issue but lost it in a move and haven't been able to find the data elsewhere. From what I remember, the truck intake did do pretty well, but as rpms increased and cam size increased, it started to fall behind. The LS6 was only off by a few numbers (5 or less) down low, but passed the truck around 5K. The FAST was a little better than the LS6 and the LS1 and Wieand were turds. I'd be willing to bet that a H/C 5.3 can see the benefits of swapping over to a LS6 or FAST 78 manifold, the FAST 90 or LS2 might be a bit much though.

Oh yeah, I also have a home ported TB being worked on that I will try on (hopefully) back to back dyno runs. Some say they are worth it, some say they aren't. We'll see.

 

Tdrumm,
Good post. You have the 'right' idea about this stuff. I've seen it in your posts. Your one of the few who are taking initiative to 'max' out the 5.3L without a power adder...
Good luck with your project.

 

yelo, he's probably just seeing what everyone else thinks:-P if people didnt ask questions then this board would be dead HAHAHA

as far as the fast intakes and etc you are looking at BIG BUCKS.. for the damn fbodies those are 1200 for the intake and TB

ive got about every friggin bolt on now also.. so next on my list will be heads and a bigger cam to help top end pull.

 

I realized I was kind of a dick when I typed that.....it was almost 2:00 AM and I was in a bad mood after just getting home from work.

tdrumm has the right idea....follow his lead and ignore my bad attitude.

 

If you do go with the 90mm fast setup check into the UMI tb it is a parabolic design which just ask Whitt1 about how much he likes it over the FAST setup.

 

I think have the article you're looking for "archived" in my catch all room. I'll see if I can dig it up a post up the results for ya.

Post up those results when you get them. Curious to see what they are...


If the FAST system is way over the top price wise, I say go for the LS6 manifold. It has quite a bit more volume than our work of art, along with shorter intake runners, which should definately let it breath up top. Drawback though, it would require the front accessory drive setup also, but it shouldn't be too hard to find one for a fair price. I think using the F/W-Body front drive setup would also free up some hp/tq. Some are against using the LS6 on our rigs, arguing the loss of low rpm TQ, but hell what TQ do you really have with the TR220 below 2K. That's why we get the stall. A set of heads done right is worth 25hp at least in my opinion. LS6 intake, a good set of heads, a nicely ported or aftermarket TB, and a hellaciously (is that a word) efficient exhaust to let it breath and I think you're there.

 

thank you for the great information tdrumm. you really got your stuff together like sport said.

as for the topic i posted, i think others could benefit from this also. it seems that when new people get here, they want more performance out of there engine and everyone puts in their head "go 6.0L" you know.

there's all these aftermarket parts for the ls1 and 6.0 bores. i'm just trying to let people share their combination and information on parts that really work for the 5.3.

like okie said, with my set up i have plenty of bottom end and if i would change to a ls6, it probably wouldn't affect it much on the lowend. my dyno graph shows my hp starts to fall off at 5600. i've seen numerous ls1's with similar cams pull all the way to 6500.

keep the ideas flowing fellas. this is a good thing...