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#57803 03/16/2006 10:27 AM | Joined: Apr 2005 Posts: 926 Shop Shark | | Shop Shark Joined: Apr 2005 Posts: 926 | Is there anyplace I can get some more info on this GMC engine I just got? I looked up the casting number on it,and it says it's 1955-1962 248 or 302,going by that. The number stamped on the pad just behind the distributor is "E 248310741"
I can't find anyplace to look this number up.
Speed | | |
#57804 03/16/2006 6:07 PM | Joined: Feb 2002 Posts: 12,029 Cruising in the Passing Lane | | Cruising in the Passing Lane Joined: Feb 2002 Posts: 12,029 | | | |
#57805 03/16/2006 11:19 PM | Joined: Aug 2004 Posts: 21 Apprentice | | Apprentice Joined: Aug 2004 Posts: 21 | The first 3 numbers on the distributor pad indicate engine size on a GMC. You have a 248. | | |
#57806 03/17/2006 6:55 AM | Joined: Apr 2005 Posts: 926 Shop Shark | | Shop Shark Joined: Apr 2005 Posts: 926 | Thanks all,
I now know I have a '55 248;it has standard size flattop pistons,and I think I'll be able to resurrect this one. The pistons are stuck,but I have them soaking,so maybe this weekend I'll be able to turn the thing over enough to remove the clutch,flywheel and bellhousing,flip it over and check the bearings.
One problem I did have though,was one of my lifters separated;the top,apparently,is pressed into a hollow body;well one of 'em was so loose it came out when I pulled up on it to check the wear on the bottom. (It's worn pretty bad.) Do aftermarket cams for the GMC six come with lifters?
I had one valve spring missing from the head when I got it. I found the keepers,but no spring or retainer. No sign of contact with piston,so I'm thinking the PO was going to do valve seals and never got it done.Maybe the valve dropped into the cylinder far enough that it couldn't be pulled back up so the owner gave up. It isn't burned,looks to have a good seal at the seat.
Also,how much can I get away with millimg the head?
I saw a tip on how to make Fenton headers for a 235 fit the GMC,how about intake manifolds-any magic tricks to make a Chevy intake fit a GMC?
Thanks again for your help!
Speed | | | | | Joined: Jun 2011 Posts: 5,096 Crusing in the Passing Lane | | Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | I milled the head on my 302, .0625", made I a tremendous difference, need to use proper size washers under rocker arm stands. especially at altitude. Can also advance timing at altitude. A 302 will also fit your truck if you look around.
Ed
Last edited by EdPruss; 08/15/2016 7:31 PM.
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
| | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 | "I saw a tip on how to make Fenton headers for a 235 fit the GMC,how about intake manifolds-any magic tricks to make a Chevy intake fit a GMC?"
Do you have the link/URL for that tip? I agree with tom moore. | | |
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