LT4 intake on a stock LT1.
#12
Join Date: Nov 2007
Location: Eastern PA,
Posts: 10,366
That too . I wanted to use the generic example. I see it so many times were guys will put an “upgraded” (single plane) intake on a 305 with a RV style CAM and they do not understand why their ¼ miles times got higher. Your best bet is to figure out what is your bottle neck then make all the other parts work with that. Just putting on bigger is not always better, unless it’s the bottle neck.
#13
The ports do match up. The LT4 has more material at the top to match the raised runner of the Lt4 head. When mounted on the Lt1 it won't let the valve cover seat properly without first being machined. There is no EGR and fairly rare, if it's cheap buy it.
#14
The ports DO NOT match up, the lt4 intake ports are bigger/raised by .10" or 2.5mm.
#18
what link??? if you can get some lt4 heads to go with the intake go for it. wish i would have being i bought a set of lt1 heads and 96 intake for mine. lt4 heads and intake port nicely.
#20
There would be no advantage to putting an LT4 intake on LT1 heads, unless it's because you like the color red. Both intakes have the same runners and the same port design (dimension and location). The LT4 intake has more material above the ports so that you could port match it to the taller intake ports on the LT4 heads. Why GM didn't match the ports from the factory makes no sense to me, probably didn't feel the "need" to. What you would need to do to use the LT4 intake though, is some "clearancing" at the valve cover rails because of the external size difference. So to boil it down, you can use the LT4 intake on LT1 heads, but you can't use the LT1 intake on LT4 heads.