77 K10 LS Swap

The engine is stock. Only significant mods would be exhaust and a lot of gear (4:56). 2k rpm is 60ish mph.

Sounds about right for a non OD standard. It's gonna be rev happy unless you go with much bigger tires or drop a couple gear steps. ON a 1 to 1 final drive 3.42 to 3.73 would be about right on a 33 inch tire, with OD people usually recomend 4.10 on a 33. That also is based on driving at highway speeds and similar driving. If you are close to town and just driving it around similarly and OK with it then sounds like it's working well. Might just burn a lot of fuel if you zip around at 70 mph.

Actually, I am running a NV4500 (OD) on 35 inch tires with 4.56 gears. Once I get a new set of tires at the end of the month, I will be able to get it out run it at speed and see what my phone speed app says I am doing. For some reason my speedometer is way off, not sure why. The speed gear in the transfer case was not changed. It had always been off by a couple MPH but now its off by 10 or better.

My bad, I thought for some reason you were running an older sm465.

No worries, that is what it had in it to begin with.

I have to admit I would like to perhaps swap an NV4500 in my Jimmy at some point but my knees garbage so I'm not sure.

Swapped out the leaky water pump today. Also found that the idler pulley has bad bearing. So need to pick up one of those and may as well get a new thermostat while I am at it.

Madhorn said:

Swapped out the leaky water pump today. Also found that the idler pulley has bad bearing. So need to pick up one of those and may as well get a new thermostat while I am at it.

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Not sure the the truck engines accessories are exactly like the LS engines but Trans Am the idler pulley bearing is serviceable. I removed the pulley, removed the cap from the bearing and packed it about 3 years ago. Hasn't made a noise since.

Madhorn said:

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Headers arrived today!!! They look great. I may get a chance tomorrow after work to try and install and check clearances.

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Who makes these, I know you had fitment issues due to the manual trans. I'm using the original sm465 and will probably run into the same. I was thinking about going with the new Hooker manifolds but may have to change my mind

The nice shiny stainless ones are made my Speed Engineering. The seem to be quality and budget friendly. Last I knew they come in a couple of styles, huggers with a vband, long tube's (not sure of the collector type) and they used to have a hugger that had a three bolt collector but that may have been phased out and replaced by the ones with the vband clamps.

I took my three bolt collectors and put my own Vbands on... My trans is the older one piece body 4l60E (looks exactly like a 700R4) and I had to chop the lower corners off it to clear the headers. Not a big deal. I doubt you will have to on the sm465 and I think many others have used both types of the Speed Engineering without issues on the SM645. The only issue I see on mine is that the orientation of the o2 bungs is really close to the floorboard but I can clock them around some and as long as they are not upside down collecting exhaust moisture they should be fine.

Yes, Speed Engineering, part # 25-1025. I was concerned about the headers clearing the mechanical clutch leakage. These headers cleared just fine. The only fitment issue was an ear on the advanced adaptors bell housing, a little trimming fixed that. Over all very pleased with the headers.

Called my local tire dealer yesterday and tried to get a set of 35x12.5x15 BFG KO2s for the 77. They said it take two weeks to get them in. Not cool. So I decided to try Tire Rack. I called them yesterday at lunch time. They had them in stock and said they could have them delivered today. Sure enough I had 4 brand new tires waiting on me when I got home. Will have them mounted and balanced tomorrow.

Tires were mounted and balanced Wednesday. Drives and rides a lot better than it did with 12 year old tires it had on it. Hopefully I have time to get it cleaned up for a local car show tomorrow. Not that the truck itself is anything to look at, but I just want to show the engine swap.

I have put about 500 miles on the 77 over the last few weeks. Average fuel mileage is 15.5 mpg. Not to shabby. Over that 500 mile run I did notice a slight vibration at 50 mph. I pulled the rear drive shaft and noticed that the u-joints were worn. The needle bearings were wareing grooves into the bearing surface. New u-joints this weekend.

Accomplished a couple things this weekend. I found out what part of my 50 mph vide was. Rear pinion pretension was loose. A quarter turn on the pinion nut worked wonders. Still need to have drive shaft checked out. I think the splined slip joint is worn out. Then I removed two leaf springs from both rear spring packs. Went from 7 to 5 on each side. Rides a whole lot better.