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John T · 02-28-2008, 06:10 PM

Does your block have an oil cooler port above the oil filter boss??

I read chevynut's post on this, and would like to know if this is true.... I am looking at a 454 powered 1976 C-10 truck soon... (junk truck, good engine) I would only like to buy it ONLY if it is a 4 bolt... kinda hard to have the owner drop the pan for me...

Chevynut wrote: "You can tell if it's a 4-bolt main by looking for an oil cooler port above the oil filter boss. If it has an extra plug there, it's probably a 4-bolt block."

exhibit 1 : I DO have a 1968 396 (4 bolt) that has the port... so maybe this is the identifying mark?

thanks..

12pack · 02-28-2008, 06:51 PM

Yes

Chevrolet by the numbers by Alan Colvin

" On all Chevrolet big block engines, the method of the crankshaft bearing cap retention (2- or 4-bolt caps) can be identified without pulling the engine apart or removing the oil pan. Just check the three exterior holes above the oil filter boss.

All 2-bolt blocks have the front hole drilled 5/16". It is not drilled or tapped into the oil galley. The center hole is drilled and tapped a 3/8" pipe thrread into the oil galley. The rear hole above the oil filter has a 1/2' USS coarse-thrread hole that is not drilled into the oil galley.

On the 4-bolt blocks, the front hole(towards the front of the engine) has a 3/8' pipe thread hole drilled into the oil galley. The center hole has a 1/2' pipe thread hole drilled through to the top of the oil galley. The rear hole above the oil filter has a 1/2" USS coarse-thread hole, Which is not drilled into the oil Galley."

I copied this straight for his book.

John T · 02-28-2008, 06:58 PM

Thank you.... !

driving55 · 03-02-2008, 12:46 AM

THANK YOU FROM ME ALSO

I did not know about this? mine is out of a1979 suburban 454 th400. from the codes in the glove box I new it was heavyduty, had tow package, big radiator, heavy duty springs, G80 code for rear axle. locker! could this be why it is a 4 bolt ?? and what are the taped holes for? "again thank you for the info" And john T thanks for asking this Question! MIKE.

02-28-2008, 06:10 PM	#1
John T Senior Member 1 Silver Star Join Date: Jan 2008 John T's Garage Location: Connecticut Posts: 590 Member #4701	454 4 bolt main owners.... Does your block have an oil cooler port above the oil filter boss?? I read chevynut's post on this, and would like to know if this is true.... I am looking at a 454 powered 1976 C-10 truck soon... (junk truck, good engine) I would only like to buy it ONLY if it is a 4 bolt... kinda hard to have the owner drop the pan for me... Chevynut wrote: "You can tell if it's a 4-bolt main by looking for an oil cooler port above the oil filter boss. If it has an extra plug there, it's probably a 4-bolt block." exhibit 1 : I DO have a 1968 396 (4 bolt) that has the port... so maybe this is the identifying mark? thanks.. __________________ True Wisdom Only comes From Pain... John T's pictures... http://www.trifive.com/forums/album.php?u=4701

02-28-2008, 06:51 PM	#2
12pack Senior Member 1 Gold Star Join Date: Jul 2007 12pack's Garage Location: Dillsboro,IN Posts: 1,663 Member #3117	Yes Chevrolet by the numbers by Alan Colvin " On all Chevrolet big block engines, the method of the crankshaft bearing cap retention (2- or 4-bolt caps) can be identified without pulling the engine apart or removing the oil pan. Just check the three exterior holes above the oil filter boss. All 2-bolt blocks have the front hole drilled 5/16". It is not drilled or tapped into the oil galley. The center hole is drilled and tapped a 3/8" pipe thrread into the oil galley. The rear hole above the oil filter has a 1/2' USS coarse-thrread hole that is not drilled into the oil galley. On the 4-bolt blocks, the front hole(towards the front of the engine) has a 3/8' pipe thread hole drilled into the oil galley. The center hole has a 1/2' pipe thread hole drilled through to the top of the oil galley. The rear hole above the oil filter has a 1/2" USS coarse-thread hole, Which is not drilled into the oil Galley." I copied this straight for his book. __________________ The older I get the faster I use to be Scott

02-28-2008, 06:58 PM	#3
John T Senior Member 1 Silver Star Join Date: Jan 2008 John T's Garage Location: Connecticut Posts: 590 Member #4701	Thank you.... ! __________________ True Wisdom Only comes From Pain... John T's pictures... http://www.trifive.com/forums/album.php?u=4701

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03-02-2008, 12:46 AM	#4
driving55 Member Join Date: Jan 2008 driving55's Garage Posts: 11 Member #4573	THANK YOU FROM ME ALSO I did not know about this? mine is out of a1979 suburban 454 th400. from the codes in the glove box I new it was heavyduty, had tow package, big radiator, heavy duty springs, G80 code for rear axle. locker! could this be why it is a 4 bolt ?? and what are the taped holes for? "again thank you for the info" And john T thanks for asking this Question! MIKE.

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