I felt the header didn't do much lce...

to have a do over...
I would take the stock one clean out the casting edges, grind it to match the head using the gasket, then put in an old o2 sensor and haul it down and have the inside sand blasted. Clean up the 2 into one part. go with 1/4 inch larger pipe or what ever slips over the out side of the stock right at the 2 into 1 part. because of the reduced size when they bend it (to tuck it up nice and tight) no cat if you can get away with it, and a quiet low back pressure muffler.

your biggest power gain is in weight reduction.
my wife and I both have 85 fuel injected trucks.
they are other wise set up about the same.

my wife's stock motor, exhaust in an 85 reg cab. 4.10 gears, 4.7 marlin's in the transfer vs dual cases, 34 inch tires.



will out run my modified motor,(2200.00$), waste of about 1200.00, (I spent money on the motor, arp bolts, built the motor to take up to 8000 rpm.. ect,,, lc header, big exhaust, dual cased, 5.29 gears, 36 inch tires, with about 350 pounds of parts in the tool box.



mine is the 3rd toyota I have built and hers is the 4th.
we have less then 1/3 the amount of money in hers then mine.
other then the paint job I often think hers is the better of the two.

what I guess I am getting at is that any where you can save money,,,, like an expensive header that won't do much, gives you money to spend on things that will. like lower axle gears, transferase gears. bud built skid plates. for the price of your header you can buy a bud built skid plate, or 4.7 gears for the transfer case... hydro assist steering is 180 bucks.. stuff like that.
now if I pulled out,, or emptied the tool box. then the power story would be different.

sorry I am assuming that you are looking for a fun, cheap, rock crawling build.