what is the difference between these two? can i make my LT1 intake into a LT4?
thanks

 

...

 

so basically no point to get a LT4 intake then... tearing motor apart to check for leaky head gasket or cracked head and was wondering, maybe i will just paint my intake red then.

 

A LT4 intake has.....

1. Red Powdercoat which is a PITA to take off
2. a .200 taller intake flange above the ports
3. a trapizoidal intake port shape vs. the rectangular LT1

Don't bother with the LT4 intake.

Bret

 

Depends on what model year of LT1 intake you are referring to. Older model year intake, yes.

 

i have a 94 lt1

 

Is there any company out there that makes an aftermarket intake manifold for LT1's or is getting the stock one ported and polished the only route to go? I've been told that the LT4 manifold is not compatible with LT1 heads becaused of the raised ports? I have AFR heads and need a manifold that will flow enough to feed my heads and cam. Anybody have any shop recommendations for machining my manifold?

 

Very few options available, because the LT1 intake flows well. Edelbrock briefly made a replacement, never sold them and never tried, because the unit offered no gains. There are services available to increase the plenum volume, which helps larger displacement engines. A "search" might find you the link. There is also an interesting custom made unit available from one of the regulars here. Do a search on "kmook" - he has one of them. Then there is always the custom sheet-metal manifolds, if you have $3,000 to spare.

The LT4 doesn't fit on the LT1 heads because the taller casting has an interference with the valve cover rail on the LT1 heads. The intake or the heads can be machined to allow the intake to bolt up. As noted in the posts above, this will gain you nothing. Although the LT4 heads have 0.100" taller intake runners, the LT4 intake, as cast, does not have the raised runners, and in fact has what appear to be a "sloppy" fit, with the trapezoidal appearance. An LT4 intake requires a lot of work to flow well/support high flowing LT4 heads. There would be no benefit in putting it on an LT1 setup.

 

Are there any significant benefits to porting the stock intake?

 

i would like to know this answer also. have the intake off right now looking over some stuff, and plan to have it powdercoated red and was also thinking of porting it for my 52mmTB and when i take my heads apart might have them bored out.

 

You don't have to have the stock intake ported for a 52mm TB.... the holes are already 52mm.

 

Fred is correct. However, I consider putting a 52 mm TB on an unaltered intake with the oem 52 dia. TB holes, breaking an old porting rule, which can apply here.
By putting components together, with each having same size openings, requires that the components line up exactly, or a mismatch, even if slightly, will result in a disruption of the airflow passing through it. The components used for lineup are not dowels, but the attachment bolts. These bolts are inserted into holes that have 'clearance designed into them, as is the standard practice for bolts/bolt holes. The component attachment here, will, with few exceptions, result in less than an exact lineup of the parts. Not a good idea, where I am from. Consider a minimum of 53 mm for the intake TB openings, in this case.