Nice, you won't be disappointed with a 12HT at all.
I agree the 4.56 are going to be too much unless you jump up to 35's or bigger.
In my BJ74, 13BT>H55F>4.10's>255x85r16's ( tall 33's) I'm running 2350~2400rpms at 65mph. Some 33's are notoriously small, I'm looking at you BFG.
On a 12HT your max torque comes around 2000ish from all I've read.
All this said, these engines will most likely run that RPM all day and not complain. You will probably however complain about noise and MPG rolling 2800+rpms all day on a trip. Most say their best mileage is under 2500rpms. Mine seems to love 2000-2200rpms
Will I suspect you will run into some alternator and ac compressor mounting issues if you decide to run ac. That early left side engine block bracket has a provision for the lower alternator which if used will not play nice with 12ht (late model 2h style) ac and alternator mount. I tried explaining this to you in your other thread but perhaps you decided not to run ac. If that is the case you also want to source the rest of the early style 2h alternator bracket (upper). Hope all that makes sense. If needed I can clarify with photos. What you technically wanted was an early 2h (hj60) left side mount or you can cut the alternator provision off yours.
Well, I figured out my (second) vacuum leak with the Holley Sniper.
The first Holley Sniper kit I purchased was from Cam Mosley at Mosley Motors. Cam has been absolutely awesome to work with and is always available for tech support. Without fail - nights and weekends - he is there to help me troubleshoot and diagnose anything going on with the Cruiser. Including parts and work he didn't provide. Top notch guy. However, his adapter plate for the Sniper FJ40 setup interfered with the heat shield/carb insulator and was causing a massive vacuum leak.
Rather than modify my heat shield, I decided to purchase the Redline Land Cruisers Holley Sniper adapter plate from Justin, and delete the heat shield altogether. The Redline plate is absolutely beautiful and machined out of billet aluminum.
(In hindsight, I wish I would have purchased his throttle cable kit instead of hacking up my throttle pedal and drilling my firewall into Swiss cheese. But I digress).
Earlier in the thread I mentioned that after installing the Redline setup my truck was running well, but was constantly making a screaming/whistling sound at idle. I assumed it was the extra fuel pressure regulator in the Sniper, because I'm running an extra LS regulator/filter. I pulled the extra FPR but it was still screaming. Finally, I took it to my buddy's shop and he diagnosed it as a vacuum leak almost immediately. Sure enough, you could put your finger on the gasket between the intake manifold and Redline adapter plate and hear the vacuum leak. I assumed that my intake manifold flange was warped because I knew the adapter plate was perfect. I pulled the intake manifold and figured I would have to get the flange surfaced and then reinstall.
After inspecting the intake manifold flange, it didn't look that warped or out-of-wack. It was marred slightly, but certainly nothing to indicate the massive vacuum leak at the gasket. For the hell of it I decided to dry fit the Redline adapter to the OEM intake manifold.
The intake manifold has four bolts that thread into the mouth to hold the adapter plate in place. Two of them are straight-through threads to the inside of the intake, and two of them are blind threads.
The Redline adapter plate kit is supplied with two sets of bolts and instructions. For the open thread ports you are to use the "long" bolts (with sealant to prevent vacuum leaks) and for the blind thread ports you are to use the "short" bolts. The problem is, even when correctly installing the "short" bolts, the bolts bottom out in the bottom of the blind threads before the intake adapter is cinched down against the manifold. The other two straight-through threads were cinched tight, but not enough to prevent the vacuum leak. I simply never noticed when I torqued them to 10 ft-lbs that they were bottoming out.
This is a pic of the two "short" bolts torqued all the way down and bottoming out in the manifold. Pretty large gap.
Initially I tried to drill and tap the blind threads, but my hand tap was too cheesy to cut the threads in aluminum.
I didn't want to break my tap, so I ended up just cutting the "short" bolts even shorter. I'll have to use sealant on these too to prevent vacuum leaks to atmosphere (since I already drilled the blind threads through).
Pretty frustrated, but glad I figured it out. Now I'm just waiting on replacement gaskets to reassemble. Should I go ahead and replace my Remflex intake/exhaust gasket since I had to pull the intake manifold? It wasn't leaking at the head before, but I don't want it to start either.
What place near Austin did your exhaust system? I like it.My fabricator finished the 3" exhaust and skid plate yesterday morning.
After buttoning up a few items, I took it for a shakedown run out to the lake. I put about 60 miles of mixed driving on it and I'm getting a LOT of gear whine at highway speeds. I'm not sure if it's the H55F, the 1.1:1/4:1 split t-case gears, or the 4.56 diff gears. It's loud AF. Spinning about 2,500 RPM at 55mph.
After the shakedown run, I have a few items I need to address:
The valve cover gasket is leaking. I installed a brand new gasket when I powder coated the valve cover. For now I am just going to snug it down and see if it will stop. If not, I'll pull the cover and try to re-seal it with some Gasgacinch.
I just vented the gas tank through the fuel separator and out the cab to atmosphere near the rear tire. On really steep grades when the tank is full, it will dump fuel out the breather line. I might route it somewhere up high to prevent dumping fuel while 'wheeling.
Finally, the Sniper is making a high-pitched whine. I think it's the fuel pressure regulator on the Sniper. Since I'm running a separate GM fuel regulator/filter, I just capped the regulator/return on the Sniper. You can really hear it at the end of the video when the engine shuts down.
I'm fine with the gears for now. I wanted the truck to be able to crawl at idle. It does that very well with the 33" tires, H55F trans, 4:1 t-case, 4.56 diffs, and ARB lockers. Is it a pleasure to drive down the highway at +60 mph? Nope. Would taller gears help? Probably. But after driving it consistently the last few months, I've realized it will never be a highway cruiser, no matter what the gearing.Just read up on this one for a friend in Louisiana you have been talking to.
Sorry about the 4.56....3.70 was the way to go.
Also, the 4:1 noise is horrific and it won’t get better. If you ever do this again get 3:1 Tcase gears. They still use the stock split case high range gear and they are quiet as a church mouse.
Sniper stuff. Lots of opinions on this but of all the ones I’ve done, the best use Mosleys adapter. Yeah, it may not sit perfect on your isolator but the key is, buy a $100 isolator from him and he can assure your adapter and isolator are perfect. I learned that the hard way.
What place near Austin did your exhaust system? I like it.
I'm fine with the gears for now. I wanted the truck to be able to crawl at idle. And it does that very well with the 33" tires, H55F trans, 4:1 t-case, 4.56 diffs, and ARB lockers. Is it a pleasure to drive down the highway at +60 mph? Nope. Would taller gears help? Probably. But after driving it consistently the last few months, I've realized it will never be a highway cruiser, no matter what the gearing.
Question for you sir JDC1I’m using 3/8” Nicopp and -6AN fittings. It takes a minute to figure out the bends but I really like doing it. There are benders available on Amazon. Brake lines in Nicopp are easy too. The cheap flaring tools are frustrating, IIRC, there are compression fittings available in AN as well.
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Question for you sir JDC1
I see you have the old style air cleaner and you have a power steering box. So my question is can you post a picture of what pump your using and the location the bracket.
Sorry for the tangent
Who is Mark A.? Does he still sell the pump/bracket?
I'm going to try it with a FJ60 pump. I have seen a picture of it done in that location . A later model wider smog bracket seems to be the path with shimmingIt isn’t exactly a drop in as it needed some adjustment to get the belt alignment perfect but that is the way he designed it.