Best way to get to ~400hp, 454 tbi. Anyone build one?

[SCOTI]

If we're needing to compare 'apples to apples', don't forget to include the cost of rebuilding the LS based motor. Last I checked (summer of '11), the cost was equal to that of a bbc.

For those that propose the LS swap in place of a bbc, I can see the benefits in efficiency but not in pulling torque. I researched LS based builds that purposely focused on torque production & not HP.... Didn't find much/any.

When I did my 7.4 rebuild, I actually had a 100K mile 6.0/4l80e sitting on a pallet in my garage. The real world numbers were $1250 to rebuild the 7.4 (new flat top cast pistons, .030" bore, fresh bearings, clean-up of the OE crank, re-fresh the PP heads w/a 3-angle valve job, Mellings oil pump, & better cam choice w/matched lifters). I was quoted more than that to go through the 6.0 (just to do it while it was out).

Then there's consideration of the actual swap cost. Heck.... just utilizing the 4l80e on the back of the 7.4 was ~$1200 (TC computer, adapter for the speedo, & convertor) so that's 1K+ just to swap in a stock 4l80e w/new equipment (not wrecking yard swap items). Ouch. Now that's not an issue for the 6.0 I already had since I got the full un-cut harness, but adding up the cost to integrate the LS wiring harnesses/re-pinning the harness for my app, air induction/intake, relocation bracket for the a/c.... all that stuff started adding up quickly.

So to me, rebuilding the 7.4 WAS real world cost effective. It wasn't $800 bucks for a crappy build. It was a little more to tweak the items that would improve torque production but was still a stock-ish rebuild.

No need for forged pistons in this app & the rebuild price included new pistons so I spec'd flat-tops vs the dished version.
No need for oval port heads in this app so I re-used the ones that I had after a good valve job.
No need for a big cam in this app. No need to keep the stock cam either. Since RV/towing cams will still work w/the ECU, I chose a better profile since it was included in the rebuild cost.

I did spend extra on a fresh Edelbrock intake & went to TBI.com for an ECU chip spec'd for my exact combo + a heated o2 sensor.

The OP asked about the best way to get ~400hp from a 454tbi but the discussion keeps drifting toward making 400 - 500+ hp from NON factory tbi induction systems or 6.0 swaps. Lets try & keep things friendly while everyone contributes....

My set-up may not be 400hp but it's better than the OE 454tbi & are simple changes in efficiency that the OP (or others w/454tbi's) can do.

[D.FENS]

Scoti - I wore myself out crunching numbers on this. I'd like to think I got it right, even though it ain't strictly apples to apples.

What I found dollar-wise was pretty much same - same as your build, with just the long block build from about $1200 low to a little over $2750 high, depending on the combo. High end being referenced off the Suburban build with forged pistons and the Comp Cams roller, mostly because I like the way it sounds in the youtube clip. The final turn-key budget of 5 - 6K includes replacing some parts particular to my build and upgrades / service parts for the TBI.

Machine shop cost is still the big unknown, I estimate it at $750 - 1000. Again, I like to build stuff once and right, would rather budget high and not need it instead of getting caught out with empty pockets. Seems as though at least one person in this thread doesn't understand that.

Didn't do a cost-out on building the LS motor, even though that skews the comparison, but LS motors are supposed to go 250 - 300K on the original bottom end. Most of what swap packages I've been seeing are something like $2200 to about $3750 (6.0 with a 4L80E), with mileage under 125K. Motor mounts, headers, a flash for the ECU, LS-specific fuel system fittings, ETC, would run the total up at least another 750 - 1,000.

I didn't do comparisons on combining the 454 with a 4L80E, just budgeted for a cheap DIY rebuild on the TH400, figuring I would upgrade later or maybe not at all.

The rest of the build budget is fixed costs that would be about the same no matter which way you go, like cooling, fuel system, and exhaust. Maybe some guys would re use an old worn out water pump and a plugged up leaky radiator, but they grown and can make they own mistakes.