Mystery block

kevdog442 · February 14th, 2009, 10:25 PM

I need help identifying an Olds block. I thought at first it was a 72 350 because it had 7A heads. (I had forgotten about the later 7A heads that had the "A" in a different position) The EGR valve also gave it away as not being a 72. The numbers behind the water pump really confused me but they are probably wrong anyway. I did my best to scoop away the grime but this is the number I got: 4790GM5-OLG...? upon researching the closest number I found was 554990 which was a '77 403. Any ideas?

dan2286 · February 14th, 2009, 10:52 PM

Im thinking its a 307. On the side of the block below the center freeze plug, it should say what size the engine is. If it is a 307 it will say 5L, it will have the cubic inches for a 350 and 403. Where did this engine come from?

J-(Chicago) · February 15th, 2009, 04:22 AM

look above the water pump next to the oil fill tube. That's the casting number you're looking for.
If that's where you found it, more research needs to be done.

kevdog442 · February 15th, 2009, 07:19 AM

Quote:

Originally Posted by J-(Chicago)

look above the water pump next to the oil fill tube. That's the casting number you're looking for.
If that's where you found it, more research needs to be done.

I got the number from that area, but there was so much crud and the guy who was selling it didn't have a flashlight. I think some of the numbers are right but not all. The side of the block would have been even harder to see.
It was in a Cutlass G body. but the guy said it was not original.

joe_padavano · February 15th, 2009, 08:30 AM

That's an 86-90 roller cam 307 block. Sorry.

February 14th, 2009, 10:25 PM	#1 (permalink)
kevdog442 Member Join Date: Jan 2008 Location: Zanesville, Ohio Posts: 37	Mystery block I need help identifying an Olds block. I thought at first it was a 72 350 because it had 7A heads. (I had forgotten about the later 7A heads that had the "A" in a different position) The EGR valve also gave it away as not being a 72. The numbers behind the water pump really confused me but they are probably wrong anyway. I did my best to scoop away the grime but this is the number I got: 4790GM5-OLG...? upon researching the closest number I found was 554990 which was a '77 403. Any ideas?

February 15th, 2009, 04:22 AM	#3 (permalink)
J-(Chicago) Seasoned beater pilot. Join Date: Jan 2007 Location: Chicago Posts: 2,696	look above the water pump next to the oil fill tube. That's the casting number you're looking for. If that's where you found it, more research needs to be done. __________________ I'd rather have a numbers matching poker hand.

February 15th, 2009, 08:30 AM	#5 (permalink)
joe_padavano Super Moderator Join Date: Mar 2007 Location: Northern VA Posts: 4,396	That's an 86-90 roller cam 307 block. Sorry. __________________ Joe Padavano 64 Jetstar 88 Conv 66 442 L-69 Conv 68 W-30 69 H/O 69 442 70 W-30 72 442 84 Custom Cruiser 86 Caprice wagon (w/307 Olds)

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
66 Delta 88 mystery wire.	ijasond	Electrical	8	October 6th, 2008 12:46 PM
Mystery Posi	2blu442	Drivetrain/Differentials	7	September 12th, 2008 07:34 PM
ID: Mystery gauge on dash	Mister	Eighty-Eight	5	January 14th, 2008 08:36 PM
mystery box	ztim	Electrical	6	November 9th, 2007 07:57 PM
Losing Water Mystery	jaco	Other	4	January 20th, 2007 07:42 AM

February 14th, 2009, 10:52 PM	#2 (permalink)
dan2286 Registered User Join Date: Mar 2008 Location: North Ridgeville, Ohio Posts: 338	Im thinking its a 307. On the side of the block below the center freeze plug, it should say what size the engine is. If it is a 307 it will say 5L, it will have the cubic inches for a 350 and 403. Where did this engine come from?