Should I rebuild the 345?

Rentalman

Rentalman

Active member
Hi All. I just have a few engine questions regarding my 74 Scout II project I've taken on. First of all it is a non-running Scout with 93,000 miles. The powertrain is a 345 choked with a bunch of smog equipment, 727 auto, Dana 20 t-case, Dana 30 front axle and Dana 44 axle in the rear. I've pulled the engine, trani and t-case. When I was trying to get access to the bolts on the tranni flex plate to disconnect it from the torque converter I was unable to turn the flexplate by hand. After I removed a few spark plugs and put a socket on the crankshaft it turned over with ease. Well I know the engine is not seized. I'm not sure the last time it ran. The carburetor was removed and is in non working order. I have service records through Sept 1996. The gentlemen that I purchased it from had it for the last 5-years in the same non running condition. No 1. Does the engine need to be gone through/rebuilt for the duration it has sat? No 2. Can I bypass all of the sensors, smog garbage and gold box and set it up like my 304 in my 800B? My 800B 304 had a stock rebuild, with all new upgraded Pertronix Coil, electronic distributor and a 2-barrel holley. It runs great after 15 minutes when its warmed up. No 3. Should I hunt for a spread or square bore manifold for a TBI system? No 4. Are these engine notorious for leaking oil? Even after my 800B's 304 was rebuilt it was leaking a few years later, I believe the rear main seal. Thanks for all of your info.
 

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I actually bought this Scout to do a swap. I just struggle with pulling the IH motor and not keeping it original. I have been thinking Gen V L83 with a 6L80 tranni. The dollar amount spent to get the 345 rebuilt with rv cam, RPT Manifold, TBI, ignition improvements and a new/rebuit 700r4 tranni will put me at near the same cost of a low mileage complete pull out of a L83 with 6L80 tranni. The swap will give me 355 hp and 383 ft. lbs of torque and better fuel mileage.
 
Sounds like you're already leaning pretty hard one direction and just looking for someone to catch you before you fall. It's too bad you weren't able to pre-prime the lubrication system and then perform a compression test on all the cylinders. Now that the engine is out, it really doesn't make any sense to stuff it back in without at least a thorough inspection and gasket seal replace. Once you plunge down that rabbit hole, it's a slippery slope to full on rebuild. Might as well while I have it out and torn down, right? You'll never get the performance and drivability from the original components that you can get from a more modern drivetrain, but if a by the numbers original resto is more important than a resto-mod then you should have the 345 gone through. Binders like to mark their territory. When they stop leaking, that's when you need to worry.
 
Scoutboy74 thanks for your input. What to do, what to do, what to do....
If I was to keep the Scout IH Powered do you have any advice on setting the engine up less the emissions junk. Obviously I would remove all emissions equipment and plug off the air injection tubes. My 800B's 304 has a PCV valve attached to the valve cover on the drivers side which has a hose that goes to the underside of the air cleaner. The passenger side valve cover has a hose with some device in the center of the hose that goes to the lower back side of carb (large vacuum outlet). Do you know if the 345 engine would run correctly if I did the same as how the very minimal emission stuff is on the 1971 IH 304?
 
This family of engines debuted with the 266 in the late 50's. They didn't have much emissions hoo haw on them at that time and they seemed to run just fine, so that isn't the question. The first thing to discover is if your 1974 year model vehicle is exempt from annual smog inspection and certification. If there's no benchmark to worry about there, then certainly you could simplify your emissions plumbing. The 345 has a similar PCV arrangement to your earlier 304. The PCV valve is located in the rear of the push rod aka valley pan cover, rather than atop the P-side valve cover. Different location, same devices and functions. I assume your desire to do this would also incorporate a carb upgrade from the smogerator Holley 2210 to something more user friendly. That would only make sense. Again, that's assuming no smog nazis to get you in a gotcha moment after the fact.
 
I do live in California. Being that it is a 1974, I believe and correct me if I'm wrong I'm not required for smog inspections. I've read that 1975 and older are smog exempt in California. I would install a Hamilton TBI system not a carburetor. Also as I've been reading multiple forums on the PCV systems. Now I'm wondering if I have the PCV system installed in-correctly on my 304. What I've read is the PCV valve would be installed on the manifold side and flame arrester to air cleaner. Mine is installed in reverse. After I had engine rebuilt and reinstalled in truck I attached everything as it was.
 
Probably exempt, but I'm up Califoregon, so I don't know about your municipality. The PCV valve, the one that rattles, should be connect to manifold vacuum.
 
Yes my mistake. On the passenger side valve cover I have a short hose clamped to PCV valve then clamped to more hose that attaches to the large barb fitting at rear of carburetor. Should that be tied into manifold instead? Driver side valve cover has spark arrestor clamp to hose that goes to air cleaner. I appreciate all of your information.
 
Rentalman said:
I do live in California. Being that it is a 1974, I believe and correct me if I'm wrong I'm not required for smog inspections. I've read that 1975 and older are smog exempt in California. I would install a Hamilton TBI system not a carburetor. Also as I've been reading multiple forums on the PCV systems. Now I'm wondering if I have the PCV system installed in-correctly on my 304. What I've read is the PCV valve would be installed on the manifold side and flame arrester to air cleaner. Mine is installed in reverse. After I had engine rebuilt and reinstalled in truck I attached everything as it was.
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I'm in Kalifunkia. Anything '75 and older do not need the biannual smognazi sniffer testing. I used to daily drive a 74 with the 258 straight six, rest in piece. I currently have a 72 and a 73 both with the same drive train as your 74
 
Rentalman said:
Scooter do either of your rigs have TBI?
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Unfortunately no. I wish my 72 had it, since it was drivable up until a couple months ago. The 727 transmission just failed on me.

BTW - I do have build threads on both. 73 beast and 72 Ole Yeller. My 72 has the most recent updates
 
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