Is this block done? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**73kay** · 07-23-2019, 11:17 PM

Hey all, I got a classic 350 that had bad blow by so I tore it down to see what was up. Had a renanufacteured tag on it but crank was .20 bearings were scored/warn, rods .10 bearing were great, and pistons were .40 over. Most of the even cylinders looked great with crosshatching intact. The problem is the driver side cylinders. 1 and 5 were the worst. They might clean up in a bore maybe but 1 has a rough texture. I’m thinking the block is done but wanted to see what you guys thought. It’s has an unknown history so idk if it’s water or something else. Looking forward to your feedback.

**73kay** · 07-23-2019, 11:19 PM

Here is the 5 cylinder with the head

**kwmech** · 07-23-2019, 11:43 PM

How deep is the water etching? Early heads 1.87 valves?

**73kay** · 07-24-2019, 12:16 AM

Quote:

Originally Posted by kwmech

How deep is the water etching? Early heads 1.87 valves?

Ya it I can feel I’m the rough part but not sure how deep it goes.

**kwmech** · 07-24-2019, 01:50 AM

With the block already being 40 over it may very well be done. Going to 60 will only allow 10 thou per side plus the power hone. Newer block may be a decent choice in regards to being roller cam friendly. It's that or a couple of sleeves

DieselSJ · 07-24-2019, 04:21 PM

Quote:

Originally Posted by kwmech

With the block already being 40 over it may very well be done. Going to 60 will only allow 10 thou per side plus the power hone. Newer block may be a decent choice in regards to being roller cam friendly. It's that or a couple of sleeves

I had to sleeve my diesel block. Whether you sleeve or trash it depends on the actual rarity of the block. Since you can get new reproduction blocks now, the value of used blocks is low unless you are looking for a period correct casting for a restoration.

**73kay** · 07-24-2019, 04:59 PM

oh ya, nope this came with the truck and is scrap if somebody doesn't get the assembly. I found the classic goodwrench 350 for $1899 on eBay from a gm dealership. They were $2200+ everywhere else. So I'll throw that in there. I was hoping to rebuild the motor and save some coin, but I don't have time to try and match blocks with heads and the machine work. Glad I found out why it was smoking! haha

68Gold/white · 07-24-2019, 05:48 PM

The pad, forward of the cylinders on the pass side bank will identify your block as to it's possible durability. If the pad is 3 to 3-1/2 inches wide, it is an early heavier cast block. If that pad is only 1-1/2 inch wide, it is a later thin block.

IF, IF it's a late block, don't spend a dime on it. If it's an early block, you have a chance at .060 over. Firdt thing is to check for cracks, then have someone sonic check the cyl thickness in it's current condition.

GRX · 07-27-2019, 06:34 AM

Agree. At 0.040 over already I would look for another block. Sleeves are perfectly acceptable when done correctly. However, good chance the mains will need to be align honed afterwards. So factor that in.

vince1 · 07-27-2019, 07:35 PM

I had a sleeved Model A block that was already .030 over. They wanted to do it to .060 but I insisted on .040 and it did clean up OK. I didn't think boring a sleeve was allowed but it seemed to be OK.

GRX · 07-29-2019, 11:13 AM

Quote:

Originally Posted by vince1

I had a sleeved Model A block that was already .030 over. They wanted to do it to .060 but I insisted on .040 and it did clean up OK. I didn't think boring a sleeve was allowed but it seemed to be OK.

Good to hear it worked out to your satisfaction. Much would depend on thickness of the sleeve wall. Boring thinner ones may change structural integrity of the sleeve and reduce the press fit. A good step at cylinder bottom during initial machining for the sleeve is critical too.

**73kay** · 07-30-2019, 12:00 AM

Thanks all for your feedback. I am waiting for the ol' good wrench to show up at my door. I guess it's just as well, since I still need to finish my shop and some other things. I kept telling myself this was the perfect opportunity for an LS, but I will save that for another day/project.

**73kay** · 07-31-2019, 07:38 PM

New motor came today!

68Gold/white · 08-01-2019, 08:34 AM

LOL< that dog will hunt!!!

Tom · 08-07-2019, 02:08 PM

Quote:

Originally Posted by 73kay

oh ya, nope this came with the truck and is scrap if somebody doesn't get the assembly. I found the classic goodwrench 350 for $1899 on eBay from a gm dealership.

Dam Im too late. A vortec longblock is only $2k.

**73kay** · 08-07-2019, 02:58 PM

I know I was tempted, but after restoring my 76, and 53 that still needs lots time and money, this blazer was a get it running project and I didn't want to fuss with fuel pumps, new flywheel, and a few other upgrades. Hell at first I was looking at finally doing an LS swap, but I just want to get her running and take the boys for a drive with the top off. haha

07-23-2019, 11:17 PM	#1
73kay Senior Member Join Date: Jul 2014 Location: Indy, IN Posts: 633	Is this block done? Hey all, I got a classic 350 that had bad blow by so I tore it down to see what was up. Had a renanufacteured tag on it but crank was .20 bearings were scored/warn, rods .10 bearing were great, and pistons were .40 over. Most of the even cylinders looked great with crosshatching intact. The problem is the driver side cylinders. 1 and 5 were the worst. They might clean up in a bore maybe but 1 has a rough texture. I’m thinking the block is done but wanted to see what you guys thought. It’s has an unknown history so idk if it’s water or something else. Looking forward to your feedback. Attached Images __________________ Andrew 1953 3100 292 T5 1985 K5 Blazer 350 700R4 208

07-23-2019, 11:19 PM	#2
73kay Senior Member Join Date: Jul 2014 Location: Indy, IN Posts: 633	Re: Is this block done? Here is the 5 cylinder with the head Attached Images __________________ Andrew 1953 3100 292 T5 1985 K5 Blazer 350 700R4 208

07-23-2019, 11:43 PM	#3
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,389	Re: Is this block done? How deep is the water etching? Early heads 1.87 valves?

07-24-2019, 01:50 AM	#5
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,389	Re: Is this block done? With the block already being 40 over it may very well be done. Going to 60 will only allow 10 thou per side plus the power hone. Newer block may be a decent choice in regards to being roller cam friendly. It's that or a couple of sleeves

07-24-2019, 04:59 PM	#7
73kay Senior Member Join Date: Jul 2014 Location: Indy, IN Posts: 633	Re: Is this block done? oh ya, nope this came with the truck and is scrap if somebody doesn't get the assembly. I found the classic goodwrench 350 for $1899 on eBay from a gm dealership. They were $2200+ everywhere else. So I'll throw that in there. I was hoping to rebuild the motor and save some coin, but I don't have time to try and match blocks with heads and the machine work. Glad I found out why it was smoking! haha __________________ Andrew 1953 3100 292 T5 1985 K5 Blazer 350 700R4 208

07-24-2019, 05:48 PM	#8
68Gold/white Registered User Join Date: Sep 2011 Location: Ark City, Kansas Posts: 3,280	Re: Is this block done? The pad, forward of the cylinders on the pass side bank will identify your block as to it's possible durability. If the pad is 3 to 3-1/2 inches wide, it is an early heavier cast block. If that pad is only 1-1/2 inch wide, it is a later thin block. IF, IF it's a late block, don't spend a dime on it. If it's an early block, you have a chance at .060 over. Firdt thing is to check for cracks, then have someone sonic check the cyl thickness in it's current condition.

07-27-2019, 06:34 AM	#9
GRX Registered User Join Date: Jul 2010 Location: MD Posts: 1,937	Re: Is this block done? Agree. At 0.040 over already I would look for another block. Sleeves are perfectly acceptable when done correctly. However, good chance the mains will need to be align honed afterwards. So factor that in. __________________ 1969 c-10 Step Side Long Bed. I-6 250cid = = 1969 Pontiac GTO hard top. 400, 4-speed.

07-27-2019, 07:35 PM	#10
vince1 Registered User Join Date: Jan 2013 Location: Calgary Alberta Posts: 1,164	Re: Is this block done? I had a sleeved Model A block that was already .030 over. They wanted to do it to .060 but I insisted on .040 and it did clean up OK. I didn't think boring a sleeve was allowed but it seemed to be OK.

07-30-2019, 12:00 AM	#12
73kay Senior Member Join Date: Jul 2014 Location: Indy, IN Posts: 633	Re: Is this block done? Thanks all for your feedback. I am waiting for the ol' good wrench to show up at my door. I guess it's just as well, since I still need to finish my shop and some other things. I kept telling myself this was the perfect opportunity for an LS, but I will save that for another day/project. __________________ Andrew 1953 3100 292 T5 1985 K5 Blazer 350 700R4 208

07-31-2019, 07:38 PM	#13
73kay Senior Member Join Date: Jul 2014 Location: Indy, IN Posts: 633	Re: Is this block done? New motor came today! Attached Images __________________ Andrew 1953 3100 292 T5 1985 K5 Blazer 350 700R4 208

08-01-2019, 08:34 AM	#14
68Gold/white Registered User Join Date: Sep 2011 Location: Ark City, Kansas Posts: 3,280	Re: Is this block done? LOL< that dog will hunt!!!

08-07-2019, 02:58 PM	#16
73kay Senior Member Join Date: Jul 2014 Location: Indy, IN Posts: 633	Re: Is this block done? I know I was tempted, but after restoring my 76, and 53 that still needs lots time and money, this blazer was a get it running project and I didn't want to fuss with fuel pumps, new flywheel, and a few other upgrades. Hell at first I was looking at finally doing an LS swap, but I just want to get her running and take the boys for a drive with the top off. haha __________________ Andrew 1953 3100 292 T5 1985 K5 Blazer 350 700R4 208



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