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Old 02-11-2025, 05:33 PM
kpbrown31 kpbrown31 is offline
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Default My 455 block dilemma

So I buy a complete (but currently disassembled) 455 last summer that was bored .030, heads had work done, new pistons, rings, cam, lifters, studs, etc. It was supposedly a complete build that never was assembled due to the guy developing health troubles.

I had took the block in to measure the main bearing alignment because the motor had been studded and I was unsure if they had align honed it. Trouble is, the machine shop just called on the block and said the caps appear to be a long ways off, and the parting lines don't even fully match on 2 caps. He said it's almost as if they are not the same caps that came on the motor. He made it seem like it would take extensive work to get them to line up right. I always thought you could still line bore and then hone most alignment issues out of them, but maybe this is way off.

Is a block without caps worth much to anyone? I'm in a predicament now as to whether I find a different block and still try to proceed with the 455 project or just sell the parts I have to recoup cost and build one of my 400's up.

The rotating assembly is balanced and I just put more money in the heads having a better valve job done, new guides and oil seals installed.

  #2  
Old 02-11-2025, 05:50 PM
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Unfortunately it sounds like you got taken, or maybe even the previous owner got taken and is the real reason why he never did anything with the block .

Anyway once the caps are too far off you will not be able to save the main bore unless you go with aftermarket caps and oversized dowel pins.

I guess it would not be too hard to sell the block and parts to someone who was planning to go with aftermarket steel caps anyway.

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  #3  
Old 02-11-2025, 06:00 PM
kpbrown31 kpbrown31 is offline
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I honestly don't think the guy I bought it from was the one doing the deceiving, but idk. It's weird because clearly someone had prepped the block. It's been bored, the ARP studs and ARP box have the torque specs wrote down for each cap and the guys name on the box. The rotating assembly has been balanced (had the machine shop double check that), new cam/lifters, 2 new intake manifolds, new piston rings in the box, carburetor, etc. It's all there, just the caps don't match up.

This was my grand plant to throw this in by summer and drive the car lol. I guess I'll try and source a different block, otherwise try to sell everything together on a package deal, not sure.

  #4  
Old 02-11-2025, 06:20 PM
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I had a 455 block that was missing the 3 center main caps.

I gave it away and it cost the recipient a significant amount to put caps on it correctly.

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  #5  
Old 02-11-2025, 06:45 PM
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Did anyone check that the caps are in the right spot, not mixed up?

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  #6  
Old 02-11-2025, 06:53 PM
Pav8427 Pav8427 is offline
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Did the seller happen to have 2 blocks layin around and got them mixed up.
Maybe even mixed up the caps on that block.

  #7  
Old 02-11-2025, 07:46 PM
mgarblik mgarblik is offline
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Please don't take my comments the wrong way. You clearly didn't start this process and ended up on the tail end of a mess. First of all, a block absolutely should never be bored without the caps installed and torqued to specs. So shame on any shop that got that far with it. There is a correct order of operation when rebuilding an engine. Clean, pressure test, or magnaflux, line hone, square decks, then BORE, hone, wash, trial assembly. In that order.

Now after that rant, back to your block. Is the shop sure they didn't mix or misplace your actual caps? Do you trust them? If you truly have a a completely mismatched set of 5 caps, IMO, unless it's a 455 SD, or possibly a 455 HO block, it is scrap. I don't mean to be harsh but to buy 5 billet caps, have them properly fitted, line bore all 5, then line hone the block, your looking at around $2000.00 around here to have that all done. Changing just the 3 center caps to billet or converting a 2 bolt to a 4 bolt block is a much easier operation than all 5 caps.
The reason is a boring attachment can be set up using the stock front and rear correct cap. The three center caps are bored based on the front and rear. If all 5 are missing, there is nothing to set up off of so the block needs to be bored in a dedicated line boring machine. The rear cap and #4 is really complicated. #4 has to have the thrust faces cut perfectly or the bearing will be wiped out. #5 has the weird shaped, complex seal groove, which will need to be machined exactly or you will have an oil leak. Using a rope seal gives you a little room for error. Overall, it's just a mess when caps get lost. I think I would tend to cut your losses if the original caps can not be found. Sorry to hear about this.

I should probably add that if someone does put 5 billet caps on the block, that's a big expense so you have to assume they are doing a high end build. By the time you do all that machining on the block to fit the caps and line bore and hone, all 8 cylinders will be out of round and out of spec. That's why we do things in order. So now the engine will need to go .040 over to straighten everything out again. Now if it's a street build, you could probably get away with it. But who would put 5 billet main caps on a street build? It gets complicated and the goal is always a really good finished engine.


Last edited by mgarblik; 02-11-2025 at 07:55 PM.
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  #8  
Old 02-11-2025, 08:59 PM
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FWIW, " Align " boring RAISES the crank in the block " most times" . Your rear main Seal, and front crank seal DO NOT move up. Probably cannot use a new style seal in rear, and need ROPE. front is a crap shoot. Have the engine " Smoked" before it leaves the stand.
Also, there was at least 3 different 455 casting numbers. The 75 and 76 can be way of in the rear of the block where the rope seal fits. Have seen the rough casting valley for seal off to side by 15 thousands. I worked with my machinist and we made a AERA bulletin on this.

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  #9  
Old 02-11-2025, 10:37 PM
kpbrown31 kpbrown31 is offline
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Quote:
Originally Posted by mgarblik View Post
Please don't take my comments the wrong way. You clearly didn't start this process and ended up on the tail end of a mess. First of all, a block absolutely should never be bored without the caps installed and torqued to specs. So shame on any shop that got that far with it. There is a correct order of operation when rebuilding an engine. Clean, pressure test, or magnaflux, line hone, square decks, then BORE, hone, wash, trial assembly. In that order.

Now after that rant, back to your block. Is the shop sure they didn't mix or misplace your actual caps? Do you trust them? If you truly have a a completely mismatched set of 5 caps, IMO, unless it's a 455 SD, or possibly a 455 HO block, it is scrap. I don't mean to be harsh but to buy 5 billet caps, have them properly fitted, line bore all 5, then line hone the block, your looking at around $2000.00 around here to have that all done. Changing just the 3 center caps to billet or converting a 2 bolt to a 4 bolt block is a much easier operation than all 5 caps.
The reason is a boring attachment can be set up using the stock front and rear correct cap. The three center caps are bored based on the front and rear. If all 5 are missing, there is nothing to set up off of so the block needs to be bored in a dedicated line boring machine. The rear cap and #4 is really complicated. #4 has to have the thrust faces cut perfectly or the bearing will be wiped out. #5 has the weird shaped, complex seal groove, which will need to be machined exactly or you will have an oil leak. Using a rope seal gives you a little room for error. Overall, it's just a mess when caps get lost. I think I would tend to cut your losses if the original caps can not be found. Sorry to hear about this.

I should probably add that if someone does put 5 billet caps on the block, that's a big expense so you have to assume they are doing a high end build. By the time you do all that machining on the block to fit the caps and line bore and hone, all 8 cylinders will be out of round and out of spec. That's why we do things in order. So now the engine will need to go .040 over to straighten everything out again. Now if it's a street build, you could probably get away with it. But who would put 5 billet main caps on a street build? It gets complicated and the goal is always a really good finished engine.
I bought the block already bored .030 over and just took it to a shop to verify everything checked out okay as far as piston to wall clearance, rotating assembly being balanced, etc. So it's possible that the previous shop (with the previous owner) mixed up the caps from another block.

But yes, the total cost to buy new caps and have that bored is far more than I'm willing to spend. I'm trying to now come across another 455 block that could possibly work. If I can't come across something reasonable then I'll just sell what I have and rebuild a 400 that I have.

  #10  
Old 02-11-2025, 10:37 PM
kpbrown31 kpbrown31 is offline
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Quote:
Originally Posted by b-man View Post
I had a 455 block that was missing the 3 center main caps.

I gave it away and it cost the recipient a significant amount to put caps on it correctly.
That's what I figure, too.

  #11  
Old 02-11-2025, 10:54 PM
tom s tom s is offline
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Check if the first and last are correct.If I had it and those were correct I would bite the bullet and get after market centers.I went through the same deal.My shop said more EZ to do the new caps than try to make caps from another engine.If the first and last are the same miss match then throw in the towel.Tom

  #12  
Old 02-11-2025, 10:57 PM
kpbrown31 kpbrown31 is offline
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Quote:
Originally Posted by tom s View Post
Check if the first and last are correct.If I had it and those were correct I would bite the bullet and get after market centers.I went through the same deal.My shop said more EZ to do the new caps than try to make caps from another engine.If the first and last are the same miss match then throw in the towel.Tom
Thanks, I'll be sure to ask. I'm going to pick up the block on Monday and get a more detailed story of what's going on vs. just a phone call.

  #13  
Old 02-11-2025, 10:58 PM
kpbrown31 kpbrown31 is offline
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Quote:
Originally Posted by nas t eh View Post
Did anyone check that the caps are in the right spot, not mixed up?
They are factory cast with the numbers stamped into the caps. When I dropped the block off I had the caps in the correct order, so they should be good to go from what I can tell anyways.

  #14  
Old 02-12-2025, 09:07 PM
soupman soupman is offline
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I had a similar experience with a seller. Many years ago I bought a 1971 455HO round port engine. The engine was installed in a GTO and the seller stated I could drive the car to test the engine. I drove the car, engine ran great, I bought the engine and the seller and his friend pulled the engine from the GTO while I waited with my pickup. They pulled the engine in about an hour. I got the engine home and my buddy said I should pull the pan to check everything, but I said it ran too good , I didn’t want to open it up. After a month sitting on my engine stand and I finally decided to pull the pan and lo and behold the original 4 bolt caps where missing and a non matching set of 2 bolt main caps where there. The bearing caps got so hot from not being correct, that they were turning blue at the parting lines. The seller must have swapped out the main caps right before I got there, knowing the engine would run ok for a short time. I found a set of used main caps and luckily I was able to have it line bored.

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