I have an LQ4/4l80 from a 2001 crew cab that I want to put in an 87 monte ss. I would like 400rwhp out of the combo.

I'm still in the learning/reading stage of the build now and tying to figure out if it's worth going to flat top pistons -LQ9/LS2 or aftermarket to bump up the compression.....while the engine is on the stand. Or can I achieve my goal by keeping the stock 317's and just do cam/headers/tune. Would L92 top end be a better approach?

 

243's, 22x/23x cam, thinner head gaskets and be happy w 425whp!!!

 

So with 243's and my power goal I should be able to fit a big enough cam without PTV problems?

 

i would agree with a l92 top end set up and an agressive cam.

 

yea, with 243 you could still get into the 234-236/239-241 range i would think

 

you could mill the 317 and get a cam from Patrick-G.will you be using the edelbrock intake ingnition kit for the transplant?edl-7118.there is a section in this forum for ls1 conversions.

 

the engine will be FI....using truck harness and computer. Most likely LS6 intake and camaro accessories.

 

Don't forget that the 4L80 will have more parasitic loss than a 4L60, much more than a manual trans. 400rwhp can happen with a moderate cam and some 243 heads. L92 heads aren't a bad way to go either, but make sure someone who understands those heads chooses the cam. Either way, compression is your friend here - if you have money for some flattops, go for it.

IMO best bang for the buck will come from some 243's and thinner gaskets. You can keep your stock rockers, use an inexpensive LS6 manifold, etc. Sell your 317's to someone looking to go boosted who needs a compression drop. They are decent flowing heads, but need some serious milling to get the compression where you'll need it.