Is the intake manifold on those engines actually plastic--or you think that one was just made that way and cut for the display like the clear valve cover? My roommate just commented on a lot of them being plastic now-days.
Yup - the block looks strong. The only things I would really question would be the rods over 600/700 HP or so and the piston ring lands if you have a bad detonation event
Highest I've seen on a 1ZZ block is like 500 somethign to the wheels but stock rods and pistons are not good for anywhere near that - the rods collapse at like 250 to the tire.
The 2ZZ on the other hand is a different story. 666 whp is the highest I've seen on one. still no block guard but it did have darton sleeves and aftermarket pistons & rods. I've seen over 500 on Mahle pistons totally stock sleeves and stock rods.
Yeah - the cooling was actually too good - they have a plastic liner in the bottom of the coolant jacket thats a coupel inches tall to keep the bottom of the jugs a bit warmer.
Do you really think the exhaust is that restrictive?
I wouldn't be too surprised that you probably wouldnt get much, if any gain at all by modifying the exhaust. Ok a different muffler may open it a little but thats probably it. Chances are if you gain in one region you are losing in another with these bolt on things.
My point is, if Toyota can gain 5 hp over the entire powerband by smoothening one bend, why wouldn't they as long as it didn't cause any problems? Thats what it is about now in 1/2 ton trucks.
Stock exhaust is always restrictive on factory trucks... I would venture to guess with aftermarket headers, delete the cats, straighten out the exhaust piping and then throw on some high flow muffers I am sure you would gain way more then 5hp....
Tundra is not a sportscar to begin with so I am sure the factory exhaust is restrictive...