4.8L Truck throttle body swap

**speed01rcr** · 10-22-2005, 07:42 PM

I don't know if anyone has done this yet, but I'm trying to find out if the electronic throttle bodys on the LS based 4.8L and 5.3L are the same size or if the 5.3L is bigger. If so, can we put the bigger T.B. on the 4.8L? It would be a cheap upgrade.

**Sarge** · 10-23-2005, 05:09 AM

Well my "off the top of my head" answer here

Yes and no....I believe they "fit" (if you have an automatic trannie you need an adapter).....so back on track here...they "fit" but you realize nothing due the heads and the velocity/flow rates of the stock heads....

**speed01rcr** · 10-23-2005, 09:41 AM

well, manual tranny is whats used. I have pretty much got every bolt on I can think of, but I always like the cheap inginuitive ones, and I think I can get a T.B. off a wrecked truck. I think the air flowing through those heads has increased slightly with the addition of the headers, exhaust, and intake I am running. Just not sure if the 5.3L T.B. bore is bigger. The electronics should just plug right in.

**speed01rcr** · 10-23-2005, 09:43 AM

I also believe the 4.8L heads are used on the 5.3, and the 6.0 300hp motors due to production costs...anyway,,,

**Sarge** · 10-23-2005, 10:38 AM

Originally Posted by speed01rcr

well, manual tranny is whats used. I have pretty much got every bolt on I can think of, but I always like the cheap inginuitive ones, and I think I can get a T.B. off a wrecked truck. I think the air flowing through those heads has increased slightly with the addition of the headers, exhaust, and intake I am running. Just not sure if the 5.3L T.B. bore is bigger. The electronics should just plug right in.

Son.... if you think your headers etc. have increased the flow of your heads...your wrong....don't mod just to mod.....if you want flow then do it....flow/velocity is realized from intake/heads/valves/exhaust...the smallest flow is realized from the choke point...in your case it is the heads......have them machined/ported/polished....or get a good set of Patriots and let her rip friend

**speed01rcr** · 10-23-2005, 01:59 PM

I agree with you on that somewhat. On a flow bench, nothing will change with the head unless some restriction is removed. But if there is less parasite friction or venturi friction, more air should flow at a faster rate...grandpa
In a venturi, pressure decreases, and speed increases. The only thing we are doing is reducing air drag/restriction. Now some may also be due to the entire assembly not allowing the heads to reach full flow potential, but in any case, the parts and tricks I have done have given a noticeable increase in power, infact, enough to beat a 305hp Nissan Titan...and mostly by flowing more air and tuning it as such.

**Sarge** · 10-23-2005, 02:09 PM

Been on the bench and have taken part in many a flow test.....I agree with some of what your saying as it relates to flow...however volumetric flow is linear....that is why turbochargers work....on stock heads.....but being linear one would need significantly more "power" to increase the flow in stock heads than a larger throttle body in a naturally aspirated motor to realize any noticeable gains........wouldn't you say?

And thanks for calling me GrandPa....got a grandson right now that calls me PeePaw....he ain't gonna live much longer