A 454 with a 2-bolt main??

[Stallion]

I was just looking around ebay and I saw a 454 BBC http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33615&item=7934931366&rd=1 and one of the specs was:

The motor is a 74' 2-bolt block that has been bored .030 over and has ...

How is that? I would have thought that with all the torque a 454 puts out it would need that 4 bolt main. No?

 

[Hib Halverson]

There were 2-bolt big-blocks...a lot of them in fact. Most Corvette BBs are 2-bolt blocks. The only ones that were four-bolt mains we the high-performance engines, ie: LS6, L88, L89, etc. Up to 6000-6200 rpm a 2-blt block and a cast crank are fine for even mildly modified engines. But, go past 6200 or so or you're making lots of power at 5500-6000 then you probably need the steel crank. Once you go by 6500 you need the 4-blt mains.

 

[67HEAVEN]

And, L-71, L-72, L-78. Dare we forget ZL-1?

Hib is correct, however, as "most" BB sold were the lower horspower 2-bolt variety.

 

[Stallion]

So what depends on 2 or 4 bolt is not torque but its horsepower? :confused

 

[67HEAVEN]

So what depends on 2 or 4 bolt is not torque but its horsepower? :confused

In the strictest sense, yes. The low horspower BBs had the same torque ratings as the high horsepower BBs.....for instance the 1967 L-36 (390 hp / 2-bolt) and L-71 (435 hp / 4-bolt) both had a 460 lb-ft torque rating.