350 4 bolt main 1 piece rear main seal - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**mkmc69** · 04-14-2009, 12:17 PM

I am looking for a 350 4 bolt main 1 piece rear main seal block in the local junk yards. I need to know what to look for to tell me that it is the block that I am searching for. Any info would be helpful. Thanks

monte0185 · 04-14-2009, 12:31 PM

Go to mortec.com they have all the casting #'s for them. Most are gonna require a visual inspection though cause they can go either way.

haysonj · 04-14-2009, 12:32 PM

I believe they are 86 and later on the one piece seals and look for one ton trucks they are usually 4 bolt mains. I don't think you can tell without pulling the pan

*MonteSS454* · 04-14-2009, 01:46 PM

87 and later are the TBI "K" motors that came with the 1 piece rear main. Get the casting numbers and head over to Mortec to verify it's a 350 and a for bolt, some will say 2 or 4 bolt so you'd have to pull the pan.

soba_03 · 04-14-2009, 02:44 PM

I have a 350 .030 block it's a 2 bolt and one piece rear main seal. Freshly punched, got a set of cam bearings and freeze plugs for it. siting in the corner of the garage. If your not stuck on a 4 bolt. I'd probally let it go for a fair price..

**mkmc69** · 04-15-2009, 09:46 AM

I was afraid of that on pulling the pan to verify, thanks for all of the help guys. Soba I will keep you in mind if I can't find what I am looking for.

chevybuldr · 04-15-2009, 10:12 AM

There is no way to tell a 4 bolt from the outside. Serious you are not really going to notice a difference in a 4 bolt or 2 bolt. Sure its nice and if you can get one then grab it. One thing about about a late motor is though make sure its not cracked in the valley(lifter area). They are notorious for cracking there, mainly accross the head bolt boss. Makes good sense to see if they offer a warrenty. Also check craigslist somtimes you can find one that is sitting in a guys garage.

04-14-2009, 12:17 PM	#1
mkmc69 Senior Member Join Date: Jan 2009 Location: Logansport,In Posts: 544	350 4 bolt main 1 piece rear main seal I am looking for a 350 4 bolt main 1 piece rear main seal block in the local junk yards. I need to know what to look for to tell me that it is the block that I am searching for. Any info would be helpful. Thanks

04-14-2009, 12:31 PM	#2
monte0185 Registered User Join Date: Oct 2008 Location: Brighton, TN Posts: 1,267	Re: 350 4 bolt main 1 piece rear main seal Go to mortec.com they have all the casting #'s for them. Most are gonna require a visual inspection though cause they can go either way. __________________ A computer once beat me at chess, but it was no match for me at kick boxing. Duct tape is like the force. It has a light side, a dark side, and it holds the world together.

04-14-2009, 12:32 PM	#3
haysonj Registered User Join Date: Dec 2007 Location: Santa Maria, Ca. Posts: 1,423	Re: 350 4 bolt main 1 piece rear main seal I believe they are 86 and later on the one piece seals and look for one ton trucks they are usually 4 bolt mains. I don't think you can tell without pulling the pan __________________ 69 Chevy 4x4 383 Power

04-14-2009, 01:46 PM	#4
MonteSS454 Account Suspended Join Date: Jun 2007 Location: Claremore, Oklahoma Posts: 821	Re: 350 4 bolt main 1 piece rear main seal 87 and later are the TBI "K" motors that came with the 1 piece rear main. Get the casting numbers and head over to Mortec to verify it's a 350 and a for bolt, some will say 2 or 4 bolt so you'd have to pull the pan.

04-14-2009, 02:44 PM	#5
soba_03 Registered User Join Date: Sep 2007 Location: Fairdale, Kentucky Posts: 561	Re: 350 4 bolt main 1 piece rear main seal I have a 350 .030 block it's a 2 bolt and one piece rear main seal. Freshly punched, got a set of cam bearings and freeze plugs for it. siting in the corner of the garage. If your not stuck on a 4 bolt. I'd probally let it go for a fair price..

04-15-2009, 09:46 AM	#6
mkmc69 Senior Member Join Date: Jan 2009 Location: Logansport,In Posts: 544	Re: 350 4 bolt main 1 piece rear main seal I was afraid of that on pulling the pan to verify, thanks for all of the help guys. Soba I will keep you in mind if I can't find what I am looking for.

04-15-2009, 10:12 AM	#7
chevybuldr Registered User Join Date: Oct 2008 Location: Livermore ca Posts: 699	Re: 350 4 bolt main 1 piece rear main seal There is no way to tell a 4 bolt from the outside. Serious you are not really going to notice a difference in a 4 bolt or 2 bolt. Sure its nice and if you can get one then grab it. One thing about about a late motor is though make sure its not cracked in the valley(lifter area). They are notorious for cracking there, mainly accross the head bolt boss. Makes good sense to see if they offer a warrenty. Also check craigslist somtimes you can find one that is sitting in a guys garage.



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