Wondering if anyone out there has any info/pics/etc on the LT4 vs. the LT1 Intake. I am told the LT4 Outlets are positioned differenty, and that they will line up with my AFRs better. I am also curious in typical performance advantages and pricing.

If anyone can help it would be MUCH appreciated, in a bind here currently.

Thanks,

Rob

 

Try doing a search on this Forum. The LT4 heads have the runners raised .100.

 

Here's a website that identifies all the differences between the LT1 and the LT4. It includes photos of a cutaway section of both the LT1 and LT4 heads, so you can see the physical differences:

http://www.grandsportregistry.com/lt1vslt4.htm

Now... the LT4 INTAKE manifold does not match the taller LT4 intake HEAD ports. The ports on the LT4 INTAKE are virtually identical to the ports on the 96/97 LT1 INTAKE... sort of trapezoidal. In effect, the INTAKE does not have the 0.100" taller ports that the HEAD has. What the LT4 INTAKE does have is more metal above the port, so that the intake runners can be ported to more correctly match the LT4 head.... but in the factoryh engines, this porting was not done. It takes a substantial amount of port work to get an LT4 INTAKE to match the flow capabilities of a well ported LT4 head.

 

Thanks for your replies. My issue is that I have AFR heads with 54cc chambers. AFR is currently advising me that the angle mill was significant such that my LT1 Intake will not line up as it should, and that I should use the LT4 Intake with my LT1 AFR heads. Now I must chase down an LT4 Intake, and check to make sure. My current LT1 Intake sits REALLY low on the Milled AFRs, the material that was removed during Intake angle correction seems extensive. Just chasing bones here, hoping eventually I will get resolution to my problems. It also would be nice to get my hands on some stock LT1 castings, to confirm the amount of material that was removed was appropriate. Measuring from the head dowel pin to the lower manifold surface on the base of the head I am seeing 6.060", whereas AFR says the stock dimension is 6.120"... and that the .060" removed is normal for a 54cc chamber. I really think I am being lead down another dead end.

Rob