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400ci rebuild, top end or crate

2K views 15 replies 8 participants last post by  TacomaEsq 
#1 ·
Hello everyone! This is my first post, but I have done quite a bit of searching around and can't seem to find exactly what I'm looking for. I've got a 1965 C-10 pickup fleetside longbed that my Dad, brother and I restored when I was about 12 years old. It had the original straight 6, but we swapped it out with a 1986 400ci with around 50,000 miles on it. It has the stock heads, but we put a mild cam and intake on it. Not long after my older brother started driving it, someone hit him and totaled the truck. We switched out frames, but it never left the garage again.

I'm a bit older now and am saving up to try and get this thing back on the road. The 400 hasn't been turned over in years. My question is: Do I need to take this thing apart before turning it over? I would change all the fluids before doing so, but should i replace rings or gaskets since it's just been sitting for so long?

IF I can get it running, do you think the best route would be to rebuild from the ground up, put a new top end, or just sell it and go with a crate motor? I know I'm giving limited info, but it has the stock heads, crank and lifters. It is also a two bolt main.

My goal is to have something that is a weekend driver, but also has some power under the hood. Thanks!
 
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#2 ·
crate engine?

As far as a crate engine it's only as good as the guy who built it. Having said that make sure you are comfortable with their warranty, return policy and shipping. Once the engine is installed it's a pain to go through these items if problems develop.

I have had only one experience with a crate engine V6 for a 2001 Camaro. It developed a lifter tapping sound after warranty expired @ 20,000 miles.

As far as starting the existing engine just change fluids and you could put a few drops of Marvel Mystery Oil in each cylinder and crank it over with dizzy wire disconnected just to lube the cylinder. I would turn the crank pulley nut with a wrench to see if every thing is free. Don't want to bend a push rod.

I am sure others have more details on this. Good luck on your project!
 
#5 ·
Thanks for pointing that out! I'll run the numbers and see what's there. I am sure it is a 400, but I obviously have the year wrong. I know you get what you pay for, but i'm trying to stay affordable and make good reliable power. I won't be racing it or anything, but I'd like something that has some kick for the weekends. I'm hoping that I can still get a reliable and powerful motor without emptying my bank account. Worst case scenario I wait a little longer and do the brakes and bed kit and put the motor off until later.
 
#6 ·
It will need "freshening". Pour a bit of Marvel Mystery Oil into the cylinders and let it "sit' for a few days. Put a socket on the crank bolt and see if it will turn. If not, rings are fretted to the walls and could damage the cylinders or pistons if you persist. A proper disassembly and inspection will be called for in that case.

If it turns, remove the distributor and with new oil, "prime" the pump with power to the gage or light, to be certain you HAVE pressure. Reinstall the distributor, prime the carb and see what happens!

Even if you aren't going to "race" it, it needs to be built in a fashion where it's reliable and serviceable. 400s can be good engines and they can also be tempermental.

Jim
 
#7 ·
Thanks for the advice Jim. The last time it was running I remember it running hot and also oil blowing out through the breather in the valve cover. I don't think the heads on it currently have the steam hole drilled so that might be a quick fix. Looking forward to taking your advice and seeing if it will turn.
 
#9 ·
That's good to hear. When it was running, we put a larger radiator in, but it was still overheating and blowing oil out of the breather. I figured it was a lack of steam holes, but maybe something else is responsible. I will am going to try and follow the suggestions on this thread and try to turn it over this weekend. Thank you everyone for all the tips.
 
#11 ·
Send me the 400. Had one out of a '81 sedan and loved it. Blew it up when oil port to rear cam bearing gunked up. Cam came apart in 3 pieces and one piece just dropped clean into the crank case at around 75 mph. Engine simply disintegrated. Evidently I didn't clean engine good nuff and some buildup in a corner someplace worked loose and got into the oil stream. I was told by 'those who know' that when GM bored out the block to 400 cid, they had to make the oil channels smaller. Never did find another good 400 at reasonable price (lots of junk out there), so ended up finally w/327 and been happy with it many years. Still looking around for a good 400. They are getting rare. I was also told that I would probably have a cooling problem because the water jackets were narrower between cylinders, but never did have problem with heat/cooling. (didn't know I had problem w/lubrication either till engine came apart)::pain:
 
#13 ·
After hearing everyone's input, I'm not to keen on selling it. Plus the shipping would be outrageous to TX. I priced out all new forged internals and a top end kit from Trick Flow. Certainly not cheap, but I was expecting a much higher total. I want to produce right about 450-475 hp and 500 tq so I think I'm going to listen to another member on here and save up for a LGT-700 to put behind it.

All I need now is a boat load of cash and I'm set. haha
 
#14 ·
Send me the 400. I send you boat load of cash. I like vinnie's thinking. I sold heads off one I had to man who kept cracking 350 heads. That was back when chevy 350 heads were cracking first time they got warm and his girlfriend let her brother drive it and got it too hot. I never did have a bit of trouble with the 400 original heads, and I run it hard. Wasn't racing it, just heavy foot on hwy, and had lots of fun w/old guy, old car (that liked to cruise at around 90 with lots of pedal left). Never did find out what top end was cause speedo only goes to 100 and the hwy patrol never did time me. They just wrote the tickets on a guess. 450-475 hp definitely doable. Chevy only put a 2bbl carb on it in cars (probably 4bbl in trucks, but don't know).
 
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