4-bolt main big blocks

[mountainexplorer]

I've had alot of 454s and other big blocks pass through my hands in the past, and never once have I had a 4-bolt main.

I got a '74 Motorhome with a rebuilt 454 thinking it should be a 4-bolt, but when I pulled it to put it in my crew cab, it was a 1978 2-bolt block someone switched with the original block.

There's another '74 Motorhome I looked at with what looks to be the original 454 in it. Who thinks that this should be a 4-bolt main block if it is original?

 

[k20]

should be, but who knows, odd things have happened. Mine is supposed to be a 2bolt, but its a 4. Even the casting number is shared between 2 and 4s lol.

 

[Cricket]

http://www.mortec.com/bbc.htm

 

[diesel4me]

pretty rare...

I've had 4 454's of my own,and seen dozens of others..only saw 1 that was a 4 bolt main,and it was a 70 Chevelle SS 454 original one, with square port heads and all the other race ready goodies factory ..one other one came into the machine shop at the parts store,but the numbers were already milled off when someone decked the block..all we could do was guess as to what it came from originally..they are very rare,always were,and are like hen's teeth now..not just 454's,but ANY 4 bolt BBC...

I've seen a few tall deck 427 truck motors that were 4 bolt mains..more common in them than cars or light trucks.. the motorhome could be a 4 bolt,but I would be suprised if it was..they usually get the same 2 bolt motor a "P30" van would,not too many are 4 bolt mains..

I don't think a 4 bolt main is so great,you hardly ever have the need for such a stout bottom end on the street anyway..unless you use nitrous,or a blower,a 2 bolt main is pretty strong..some claim drilling and tapping the block and using the "splayed" caps and bolts in the conversion kit are actually stronger than a stock 4 bolt main setup..nice to have,but a bit overated in my book..

 

[gauder]

This is what I use: http://www.cnc-motorsports.com/product.asp?ProdID=14199&CtgID=

 

[79k20350]

The 454 4 bolt mains are fairly uncommon. their ls6 blocks. My dad had one in his 72 camaro that he built, had abot 650hp n/a too Now thats how you build power! the 454 in that chevelle, the ls6 was an option over the ls5. most people didnt go for the option in these cars and thats why their rare. it wasnt a cheap option either

 

[mudjunkie 82]

Check by the oil filter and see if there are plug in the block for an external oil cooler