Is there a big difference between the LT1 and LT4 intake manifolds? If so, what are the differences? Are all parts interchangeable or does the LT4 require different injectors, throttle body, etc.? Thinking about buying an LT4 intake for my car, but I am unsure of the power increase if any. Any info will be appreciated.
Thanks.

 

The LT4 manifold is specific to the LT4 heads. The runner angles are slightly different and don't line up exactly. All the other parts are the same. If you just like the look, get yours powder coated. I got mine power coated and then ported it to match my heads. It looks bad *** and was cheaper too.

 

The LT1 intake can also be ported to flow just as well as the LT4 intake. Actually an LT1 intake can be ported to outflow an LT4 intake pretty easily. The LT1/LT4 intakes both can be ported easily for 58mm-mono blade TB's the same. I would say stick with a heavily modified LT1 intake manifold over an LT4 if you're going to only do bolt on's and such. If you plan on AFR heads and going big cubes then plan on an LT4 intake in you're near future. They are starting to be able to be picked up pretty cheap if you know where to look.

 

As received from the factory, there are only three differences between the LT1 and the LT4 intake manifold. 1) red powder coating on the LT4; 2) interference between the LT4 intake and the LT1 head valve cover rail that prevents the LT4 intake from fitting correctly on LT1 heads. The heads or the intake need to be machined; 3) a little more metal at the top of the LT4 runners that allows the LT4 intake to be ported to match LT4 heads (the runners do not match on the stock LT4 intake - strange, but true).

As received from the factory, the LT4 heads have a 0.100" taller intake port. But the LT4 intake does not match these, having a port that is virtually identical to the LT1 port. Seems like GM ran out of money during the LT4 development program . It takes a lot of porting work to get an LT4 intake to support really well-ported LT4 heads.

Might want to do a search. This topic gets covered maybe once a month, and some of the threads have links to photos showing the LT4 ports vs. the LT1 gasket.

 

Ok, you guys have been a big help! Thanks for all the info.