I was talking to a family friend who does exhaust work on street rods who was telling me that using an 1 3/4 primary tube header for a 5.3L motor with a TVS1900 might be TOO large of a primary tube. He was telling me that the larger tube headers on smaller motors like that can kill the bottom end in them as apposed to using something with 1 5/8 primary tube on it. I am pretty sure that he was talking about making ZERO changes to the motor in order to take advantage of the larger primary tubes (like take advantage of less problems with knock retard at higher boost levels on the street maybe). He was saying that the larger primary headers might make more PEAK power but have less bottom end power for that TVS1900 on a 5.3 motor....Is there ANY thruth to this? Does anyone have any first hand experience with long VS short tube headers on an LS1 or an LM7 blower motor?
I asked him if maybe people use the larger tube headers because they don't have as many knock problems at higher boost levels on the street. like when the grand prix GTP guys go to headers to allow for more boost than using the stock manifolds. Is it in the TUNNING that the long tubes shine and he is just talking about a STOCK motor, or a motor that someone swapped to larger tube headers and didn't tune for them? I am asking because I want to buy some headers for a TVS1900 on a 5.3 set-up but I want to make sure that I do it right the first time....peak power is cool and all....but if the shortie headers with smaller primaries would make less peak but more USEABLE power in the lower RPM's because the motor is in my RCSB silverado I would buy those...

What do you guys think....

 

Look use the KISS method and don't over think it. Ive done a lot of trucks with 5.3's none with the 1900 though. And the exhaust as far as headers etc... Makes very little difference at all you are not at a HP level that it is going to make a huge difference at all. I say this as long as the cats are gone and you have a decent cat back the gains are going to be minimal from one option to the next. You will make a lot of power down low inherently with those style blower that you won't be able to utilize all of it with out some very serious suspension mods etc... So I like the bigger primaries myself and from what I have seen they gained across the board and not just in peak power. But with that said if I was on a budget a set of Pace setters would be my first choice. I mean you are not building a race truck no offence. I wouldn't spend the extra money for the larger Kooks etc... Unless I just had disposeable income etc... GL! What ever you do will be fine and it will run very well.

 

The logic with smaller primaries are true to some degree with NA engines. With a positive displacement supercharged engine, I don't think it applies.

 

thats kinda what I was thinking man.....I'm not building a race truck, but I do have a couple traction mods to take advantage of the bottom end the blower gives me.....I have caltracs with RS9000's, and some 28inch ET streets.....I havent been able to run the truck at the track to sort out the rear set-up yet but I will be deploying six months from now so I am just gathering cash and knowledge for when I get back....gonna go with an 80E swap and a 14 bold, with 1530 joints, and a 2600or 2800 stall......I almost have the cash together for the driveline swap, but I figure that I would just spend like 3-4 weeks of leave when I get back enjoying my garage and speed parts.....
I'm trying to get the truck into the high 11's....the blower will come from the cash I save on cruise....and I'm going to use a GT2-3 cam in it.....I think I can run LOW 12's with that or high 11's......truck should make the power to run that.....the 60ft is going to be the questionable part.....should be able to hook with some decent track time and a stenno notebook....LOL...low tech, but effective way to mess with the shock and caltrac settings....

 

You can add the weight of a 14 bolt if you want, but the stock rear end with a few part will hold up to way more than your going to throw at it. Other than that sounds like a good plan.