lq4 build which heads?
08-23-2014, 10:45 PM
#1
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lq4 build which heads? Im planning on swapping a LQ4 into my old shortbed this winter. Eventually id like to turbo it but initially im gonna run all motor. I was thinking of using the LQ4 shortblock with ARP rod bolts and head studs, and holley hi ram. Should I go with thr L92 heads or stick with the factory 243's. The NA cam that cam motion suggested is 236/249 .646/.629 111 LSA with 4° advance built in. This is going into a 3800lb 2wd pickup with a 4l80e 3500 stall
08-25-2014, 08:49 AM
#3
With the 243's, you should see a compression ratio of 10.2:1. I think that would be better for an NA street engine, especially if it's going into a heavy truck. Depending on how much boost you want to run, that compression ratio might still be okay with the turbo you plan to do later on.
With the L92's, you should see 9.8:1. That would probably be better with the turbo, but might make the engine seem weak in NA trim, especially with the cam you mentioned.
If it were me, I'd run the 243 heads for now. When you want to turbocharge it, swap the heads for 317's to drop the compression ratio, and since it's also a cathedral port head, you don't have to change the intake manifold.
With the L92's, you should see 9.8:1. That would probably be better with the turbo, but might make the engine seem weak in NA trim, especially with the cam you mentioned.
If it were me, I'd run the 243 heads for now. When you want to turbocharge it, swap the heads for 317's to drop the compression ratio, and since it's also a cathedral port head, you don't have to change the intake manifold.