Picking up a 400 SBC - Page 7 - Chevelle Tech
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post #91 of 99 (permalink) Old Feb 28th, 20, 9:30 PM
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Re: Picking up a 400 SBC

Here is a 406 I got from a guy for $100 a couple of years ago, I went through it and am in process of running it with some Vortec heads.
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post #92 of 99 (permalink) Old Feb 29th, 20, 4:47 PM
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Re: Picking up a 400 SBC

Flat top 406 with Vortec heads? About 11.5-1 c/r, what fuel are you going to run.
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post #93 of 99 (permalink) Old Feb 29th, 20, 6:21 PM
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Re: Picking up a 400 SBC

HI
Any mains caps that are replaced require line hone , to size the cap for correct bearing clearance . Similar to resizing rods . Once you have seen really bad conrod bearings u understand why resizing is a good idea . The wear pattern on bearings goes real bad not even at all .
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post #94 of 99 (permalink) Old Feb 29th, 20, 8:36 PM
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Re: Picking up a 400 SBC

Quote:
Originally Posted by Aaron View Post
Wanted to give you my update on my 400 sbc find.

Yes, it was a virgin bore 400. Full deck height.

Everything looked real good on first inspection.

Had NO cracks in the usual spots on the 400.

The machinist sent it to the hot tank and it came back looking real good.

Upon inspection of the caps, he found that the oil pump main had cracks in it and another crack in the bolt boss.

So...its no good.....back to square one. Have less than 800 in this block, but its less than 800 down the tubes....

Should of just saved an bought an aftermarket block. Would have a good chunk of that done.
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Picked up my block today and I have a question.

I didn't ask my machinist about this, but he indicated its very expensive and kind of pushed it aside, so I didn't inquire more. He doesn't have the machine to do the job anyways.

I think the block itself is ok, its just that rear main cap that has the damage and cracks to it.

I already have the studs of the block.

Can I just replace the rear main cap? Im not building a racer here. Just a stout cruiser at around 550 horse.

If so, how much would I be spending on making this repair?
Line honing isn't that expensive but that main cap is a different size than a standard SBC I believe.Then it might be a little hard to find.With the money you already have in that block I hope you can fix it.I think you should put a WTB in the classifieds maybe someone has the caps off and old 400 block that they scrapped.
If you can't find the main cap you need there are options available still.Do you still have the crankshaft from that 400 ? If so after machining that crank can be used in a 350 block to make a 383.A little less cubes and you lose out on that BIG 4 1/8th bore but still a good engine.
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John
71 El Camino SS
406 SBC M21 3.31 12 bolt
"Quality is always remembered,long after the price is forgotten"
"I would rather have questions I can't answer than have answers I can't question" :R.Feynman
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post #95 of 99 (permalink) Old Feb 29th, 20, 10:04 PM Thread Starter
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Re: Picking up a 400 SBC

Quote:
Originally Posted by 71350SS View Post
Line honing isn't that expensive but that main cap is a different size than a standard SBC I believe.Then it might be a little hard to find.With the money you already have in that block I hope you can fix it.I think you should put a WTB in the classifieds maybe someone has the caps off and old 400 block that they scrapped.
If you can't find the main cap you need there are options available still.Do you still have the crankshaft from that 400 ? If so after machining that crank can be used in a 350 block to make a 383.A little less cubes and you lose out on that BIG 4 1/8th bore but still a good engine.
I like your suggestion of finding a whole new set of main caps. I haven't thought of that.

I wondered why my machinist didn't make mention of this.

The cap that is no good the rear one, that the oil pump bolts to.

I do still have the crank. I actually have two 400 cranks laying around.

67 chevelle malibu / SS/ custom

Currently undergoing a metal work to remove all rust, if I ever get there.

Cant decide on prostreet or cruiser with a 4 speed.
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post #96 of 99 (permalink) Old Mar 1st, 20, 1:27 AM
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Re: Picking up a 400 SBC

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Originally Posted by nitrofox View Post
Flat top 406 with Vortec heads? About 11.5-1 c/r, what fuel are you going to run.
110 Renegade from the local oil co.


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post #97 of 99 (permalink) Old Mar 25th, 20, 7:35 AM
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Re: Picking up a 400 SBC

If you have not found a set of 400 main caps, let me know. I know a couple of guys that may have a set laying around.

I did get my 400 back from the machine shop just before the state closed everything down. Just for everyone information I had the block cleaned, crack checked, align honed, decked, bored and honed - the bill was around $950. Keep that in mind when purchasing a used block - mine was basically free, it came in a vehicle I bought assuming the engine was not good. My assessment was close because all I could save from the 400 was the block - heads and crank were bad and I am using 5.7 rods so I never checked the 5.565 rods. The block did clean up a .020 over (4.145 bore)!

It was still less than a Dart block, but the Dart block has some features that make it a better block.
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post #98 of 99 (permalink) Old Mar 25th, 20, 9:14 AM
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Re: Picking up a 400 SBC

^ Good for you at .020 - that should make for at least one more safe rebuild. I had 1 of 4 do that but the other 3 cleaned up nicely at .030.

Gary Adrian
Organized people are just too lazy to look for their stuff...
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post #99 of 99 (permalink) Old Mar 25th, 20, 9:31 AM
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Re: Picking up a 400 SBC

I am really happy at .020" over! Have had 3 in the past clean up at .020" over, a couple at .030" over and 1 at .040 over. The .040 over was a stock rebuild and I kept getting bugged by a guy who wanted it for '56 Bel Air 4-door. Since it was not a hot rod he has not had any issues with it, just takes it out a couple time a week to show it off or get ice scream. He is in his 80's so I don't think it will ever get run hard.
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