454 2/4 bolt main ??'s

[big_truxx]

i already have slapped myself for not knowing the answer to this; did the 454 have both 2 and 4 bolt main blocks?

 

[nvrenuf]

Yes, I have one of each right now.

 

[big_truxx]

hmm one would be able to tell that from the #'s on the block right? and does it really make a difference either way?

 

[jakt]

it might possibly for sure be a 2 bolt.....maybe.
But seriously, clear up 30min on your next oil change and take the oil pan and all its related paraphernalia off and have a look see. should be right there for you in all its multi-bolted glory.

 

[nvrenuf]

The casting #'s aren't 100%, I've seen the # for my 4 bolt (last 4 = 5445) also on a 2 bolt. You'd have to either pull the pan or at least pull the timing cover (from here you can see if the the front cap has 2 or 4 bolts).


Did you need it, not really. It's good insurance and great novelty but I've always read that the 4 bolt main is not needed until you're at or above 600 hp.

 

[big_truxx]

since im not into dragging my crew duallies, i doubt that 600hp will EVER be under the hood more than 600ft lb of tq maybe but definately from a CAT at that point thanks for the info.

 

[thor]

The casting numbers won't tell you, but here is some info that may... All gen 5 and 6 blocks (one peice seal) are 4 bolts, A MKIV 4 bolt block will have provisions for the oil cooler tapped in the block

Edit: Fixed it... Had some bad info, clearified on next post.

 

[big_truxx]

The casting numbers won't tell you, but here is some info that may... All gen 5 and 6 blocks (one peice seal) are 4 bolts, also all with factory oil coolers are 4 bolts. A 4 bolt block will have provisions for the oil cooler tapped in the block, and if the cooler is not used they will be plugged... These are not tapped in a 2 bolt.

thats cool. what years are gen 5 and 6? and are you reffering to the oil cooler thats built into the radiator?

 

[4X4HIGH]

The casting numbers won't tell you, but here is some info that may... All gen 5 and 6 blocks (one peice seal) are 4 bolts, also all with factory oil coolers are 4 bolts. A 4 bolt block will have provisions for the oil cooler tapped in the block, and if the cooler is not used they will be plugged... These are not tapped in a 2 bolt.

I don't know about the later gen V and VI blocks but the earlier BBC did not use a tapped hole for the oil cooler it used an adapter that mounted between the block and oil filter and they came both 2 and 4 bolt mains.

 

[ssls6]

If the galley plug above the oil filter is tapped with a 1/2" pipe thread, it is a 4-bolt. If the thread is a 3/8" pipe thread, it is a 2-bolt. This is true for all the mark IV blocks I've looked at.

RLK

 

[4X4HIGH]

If the galley plug above the oil filter is tapped with a 1/2" pipe thread, it is a 4-bolt. If the thread is a 3/8" pipe thread, it is a 2-bolt. This is true for all the mark IV blocks I've looked at.

RLK

This info is not correct either. I have tore apart many BBC's with the tapped hole being 3/8" NPT and they were 4 bolt mains. There is no definate way to tell 2 or 4 bolt on a BBC unless you drop the pan or timing cover.

 

[thor]

OK, here is the back up to my original post on the provision for an oil cooler.

Look on your block, the hole that is larger in a 4 bolt block is not the 3/8" one that your pressure sender is in, it's the next one forward, is an 1/8" pipe plug on the 3 2 bolt blocks i have, it should be 1/4" npt on a 4 bolt. The only 4 bolt I currently have is a gen 6 block so i can not confirm this. Any one have a known 4 bolt block they want to check?

"Chevy Power" Copywright 1994 General Motors Corp, 7th edition 2/94. This is the engine prep and blue print book sold and produced by GMPP. On page 146 states that:
"All high performance MKIV blocks have provisions for oil cooler fittings located above the oil filter pad. To connect an oil cooler, first remove the factory installed pipe plugs, then install filter bypass valve (PN 5575416) in the rear hole behind the oil filter adapter bolt to route oil to the cooler."
It also shows a detailed picture with the oil passages of a 4 bolt block labled.

 

[tarussell]

OK, here is the back up to my original post on the provision for an oil cooler.

I did not say the holes were used, just that they are there. Look on your block, the hole that is larger in a 4 bolt block is not the 3/8" one that your pressure sender is in, it's the next one forward, is an 1/8" pipe plug on the 3 2 bolt blocks i have, it should be 1/4" npt on a 4 bolt. The only 4 bolt I currently have is a gen 6 block so i can not confirm this. Any one have a known 4 bolt block they want to check?

"Chevy Power" Copywright 1994 General Motors Corp, 7th edition 2/94. This is the engine prep and blue print book sold and produced by GMPP. On page 146 states that:
"All high performance MKIV blocks have provisions for oil cooler fittings located above the oil filter pad. To connect an oil cooler, first remove the factory installed pipe plugs, then install filter bypass valve (PN 5575416) in the rear hole behind the oil filter adapter bolt to route oil to the cooler."
It also shows a detailed picture with the oil passages of a 4 bolt block labled.

I have heard this in the past and it has not failed , from what I have seen , yet. I always tell folks to verify it with thier own eyes but like I said - this theory seems to be very true on the Mark four series 454's .
I have been involved with more BBC's than I care to remember and this combination holds water to date !
Tom

 

[big_truxx]

cool thanks for all the info. Learned some good things. :Waytogo:

 

[BAJA_BLAZER]

4 Bolt? 2 Bolt?

This info is not correct either. I have tore apart many BBC's with the tapped hole being 3/8" NPT and they were 4 bolt mains. There is no definate way to tell 2 or 4 bolt on a BBC unless you drop the pan or timing cover.

I have four Gen IV BBC 454's in my garage right now. Two of them have the oil pans removed. One is a 4 Bolt and the other is a 2 Bolt and both have the same oil galley port configurations with the same size plugs. Both vehicles had factory oil coolers and used the adapter between the block and filter. They are identical. From everything I have read and witnessed, there is no sure way to tell what you have without counting the bolt holes yourself. I also have a 2 Bolt with a forged crank and 4 Bolts with cast cranks. “BBC’s are like a box of chocolates; you never know what you are going to get until you look inside.” Forrest Gump’s mother.

 

[big_truxx]

“BBC’s are like a box of chocolates; you never know what you are going to get until you look inside.” Forrest Gump’s mother.

thats a good one.