Engine block machining.

[-83MONTESS-]

I have a chance to buy a completely remachined 4 bolt main .060 overbore 454 block for $500. The work has been done recently and a new set of ARP main studs are included. Would it be a good idea to buy a block that has been bored and honed without the pistons im going to use? I know you're supposed to have the pistons for honing. I currently have a stock 2 bolt main 454 block I was gonna machine myself for my 496 build in class but now im wondering if my money would be better spent on one thats done. Anyone have any thoughts? Is $500 too much?

 

[DRIVEN]

Let me preface this by saying I'm not a big block guy. If I equate this to the SBC world then add 50% BBC tax, $500 is pretty much top dollar to me. Maybe a 4 bolt BBC is much more rare than a 4 bolt 350. Either way, block machining isn't terribly expensive so I have to assume that "value" is in the 4 bolt mains. As far as finish honing goes, yes, it's preferable to have the pistons first. Not necessary though. Just check you clearances before assembly. You'd probably be fine 99% of the time with any off the shelf pistons. Also, I try to avoid blocks that are used up. Is .060" considered max overbore on a BBC or do they go bigger? It'd be nice if you have another rebuild left in it.

 

[G-Body_Vet]

I wouldn't buy a machined block unless it comes with some paperwork from the machine shop. I'd want to know if it's been mag checked for cracks and sonic tested for thickness if the .060 overbore is a concern. Like he ^^^^^ said, if .060 is the max overbore then that block may be on it's final rebuild.

Do you know if any work has been done to the mains and does it come with the main caps? Has it been decked or did it need it? Was it bored with torque plates or does that matter to you? Have you seen this block yet? There's so many things that could make this a good or bad deal. GOOD machine work adds up pretty fast.

Prices may be different in your area but here's what my work cost on my Pontiac 455:

Thermal clean & mag check $135
Sonic test & bore inspection $70
Bore & deck block w/plates $280
Line hone main bores $185

All of my work included a complete report of top, mid & bottom cylinder thickness; wall thickness at the inboard/outboard thrust, and minimum side thickness. Overkill? Maybe....but I'd rather know what I have before dumping money into it, rather than be sick after something catastrophic happens and realizing how much money I pissed away.

 

[hurst1979olds]

Do it yourself in class. You'll save money, plus when I machined my block myself in class....it feels good saying I did that.

 

[online170]

If the guy has a bare block, get/borrow some measuring equipment and go and measure everything. Pistons nowadays are pretty tightly controlled, and if you are getting forgings especially, you will know what the piston size will be before you ever buy it. The size of the pistons will start to matter with Hypereutectics since the running clearance is so tight.


Check the bore sizing. Check the deck for straightness. Check the line hone for straightness. Check the line hone bore.

DO NOT ASSUME ITS CRACK FREE!!!! Unless he tells you its been crack checked. Ive seen machinists run the "whole 9 yards" treatment on a block, and discover a crack they missed at the assembly stage. Then try to pawn the block off to someone who is unsuspecting.






The pricing isnt hard to figure out, and the 4bolt main is not as special as everyone wants it to be. The 2bolts are usually more desirable now because they can have splayed caps installed. Unless youre planning to rev to 6500+rpm, I wouldnt worry about it. Or if you think it some how raises the value, then ya, go for it.

Your existing Block -$0
Clean, deglaze and crack test - $125-$150
Bore+Hone - $200-$250 (more if you use a deck plate)
If thats all youre doing, then that block is too expensive at $500.


If you do more, like line hone, and deck cut, then it becomes a better deal. Just make sure if you buy it that it checks out to WHAT YOU NEED IT TO CHECK OUT TO, for the combo youre running.

 

[-83MONTESS-]

Do it yourself in class. You'll save money, plus when I machined my block myself in class....it feels good saying I did that.

I forgot you went to UNOH also. I have Custom Engine Building this session and this was going to be my project. We can do everything but crack testing from what im told.

Also, I try to avoid blocks that are used up. Is .060" considered max overbore on a BBC or do they go bigger?

Depending on the casting numbers alot of 454s can go .120" over but must be sonic tested. Im stuck with a .060" overbore because I already have forged .060" overbore dome pistons and I will not be buying new pistons.

If I were to go the route of buying this I wouldn't pay $500 but he says he doesnt have to sell it so im not sure how much I could talk him down. It has been awhile since I have run the machines but shouldnt be too hard to relearn. Me and my Mopar buddy bored a 302 Ford out until we hit coolant passages :lol: Thanks for all the advice/info, im definatley more confident in doing it myself. Plus that means more money for go fast parts.

 

[hurst1979olds]

Do it yourself in class. You'll save money, plus when I machined my block myself in class....it feels good saying I did that.

I forgot you went to UNOH also. I have Custom Engine Building this session and this was going to be my project. We can do everything but crack testing from what im told.

Also, I try to avoid blocks that are used up. Is .060" considered max overbore on a BBC or do they go bigger?

Depending on the casting numbers alot of 454s can go .120" over but must be sonic tested. Im stuck with a .060" overbore because I already have forged .060" overbore dome pistons and I will not be buying new pistons.

If I were to go the route of buying this I wouldn't pay $500 but he says he doesnt have to sell it so im not sure how much I could talk him down. It has been awhile since I have run the machines but shouldnt be too hard to relearn. Me and my Mopar buddy bored a 302 Ford out until we hit coolant passages :lol: Thanks for all the advice/info, im definatley more confident in doing it myself. Plus that means more money for go fast parts.

Why cant you crack test? You were able to in Regular Machining and in Customs when I was there....Whos your instructor? I line honed, square decked the block to 0, and bored and honed it in Customs. The automated Sunnen they have there is t*ts. You set the crown wheel for the material to remove, and it does it itself. Its self adjusts for taper and everything. Good luck with your Big Block

 

[-83MONTESS-]

Why cant you crack test? You were able to in Regular Machining and in Customs when I was there....Whos your instructor? I line honed, square decked the block to 0, and bored and honed it in Customs. The automated Sunnen they have there is t*ts. You set the crown wheel for the material to remove, and it does it itself. Its self adjusts for taper and everything. Good luck with your Big Block

I was told that that was the only thing I couldnt do. I havent asked Mr. Comer yet---hes my instructor. He gave me sh*t about putting my block in the shot blaster when I had machining so I hope he remembers it :lol:

 

[G_Body_Enthusiast]

i would use what i had rather than buy another of what i already have. the math says to use your block and do the work in class, it's practically free!

 

[DRIVEN]

^^^And take lots of pics for a build thread.