400hp/400tq goal in CA. Swap or modifications?

[jollyjerry]

Have a 1998 K1500 5.7 with a 4l60e. Fine with the truck, but like using it to learn new things on. Never done anything that adds power, so started researching either modifying the current engine, or swapping in something newer. Had some open questions, but just want to hear from folks who have gone through the process and their reasoning.

• CA allows swaps from newer or same year vehicles from the same class. So a 6.2l L99 would be good for my target numbers. Or a 454 with work. I would need all the original emissions equipment including the gas tank
• CA modifications requires aftermarket parts with an EO (executive order) on them. Means the part is approved to be emissions compliant. Ideas include hotter cam, new computer and tune, porting, rebuild
• A swap means I can still use the truck for junkyard runs during the build
• In either case, seems like trans would need to be built up or swapped to something else. Looked at 4l80, t56, nv4500. Also 4l65 and 4l75

 

[Biggershaft96]

ls swap is pretty much the only solution. you obviously wont be able to run to the junk yard with it while the motor swap is in progress. I would do all the modifications to the new motor before you pull the 5.7, then take a weekend (or week) to swap it in. theres not really any way a 5.7 vortec will ever make 400hp without extensive modification. hell the ht383 doesn't even make 400hp. as far as transmissions go, exclude the 4l60e just because its junk, t56 wouldn't be ideal at all since the first gear is pretty tall and your truck is 4x4. idk about 4l65s or 4l70s. best bet would be nv4500 or a 4l80e, both of which require new driveshafts and a different tcase (unless you swap the input shaft on the tase). I have no experience with a 454 but ive heard with a cam swap and some better flowing heads theyre pretty impressive, but you could probably make the same power cheaper with a ls. emissions is also something I have no clue about since I live in Indiana lol.

 

[Supercharged111]

Screw all that, if you're going LS do a GenIV 6.0 or bigger and grab the 6L90 and t-case that comes with.

 

[jollyjerry]

Screw all that, if you're going LS do a GenIV 6.0 or bigger and grab the 6L90 and t-case that comes with.

Found a L99/6L80e swap into a 95 C1500 at http://67-72chevytrucks.com/vboard/showthread.php?t=725451

Imagine this will take more work to line up the t-case and front axle. Definitely intimidated by the swap.

 

[Supercharged111]

If ya get 'em both with harnesses and computers it's no worse than a Gen III swap. If that's a 2wd setup you'll need to convert to 4wd. Not worth it.

 

[Biggershaft96]

Ya a 6 speed would be nice. I never really gave that a thought.

 

[c1500deathtrap]

You can hit 400 with heads cam and intake. Long tube headers will certainly help as well.

 

[jollyjerry]

You can hit 400 with heads cam and intake. Long tube headers will certainly help as well.

Recommendations for specific builds or parts you've seen? Will do more searching in the evening also and paste them here as I find them.

 

[Supercharged111]

370 is easy NA, 400 is doable but seems like torque may suffer. Dat 6.2 tho. . .

 

[jollyjerry]

370 is easy NA, 400 is doable but seems like torque may suffer. Dat 6.2 tho. . .

400/400 isn't a hard target. The way I drive, I'd prefer more low end torque at the expense of peak power anyways. Agreed the 6.2 is appealing, but then I'm asking myself if I want to find a rcsb rwd + manual for a sport truck, or a ccsb if I'm going to put the work into it.