Can you buy an LT1 with 4 bolt mains from GM? Or anyone? Or do you have to get lucky and get one out of a vette or something? Does anyone know a good 4 bolt main conversion kit? I would have my local machine shop install them. Thanks

 

When I got my motor replaced with a GM crate motor ordered from a dealership, it came with 4 bolt mains.

 

To my understanding, all replacement engines were left over Corvette engines and are 4bolts.

Jonz_z: GM dosn't make LT1 blocks anymore, so you have to find another source.

 

Was not a brand new motor, think it was a refabbed one, got it from a dealership though. At least that's what the invoice said. But it did have 4 bolt mains.

 

Got LT1, that sucks the dont make them anymore. I see you are loookin for one also. Is it expensive to have one converted? I was looking in summit and the have Milodon's for about 215.00 Anyone know machining costs?

 

It just cost me $700 to have mine converted to 4 bolt mains.

 

OMG that is a lot of money for 4 bolt mains. How did it end up being so much? Does anyone know how much HP the 2 bolt mains can take?

 

Machine work and the billet caps. I think I am on the high side. I think $600 was average when I did the research several months ago.

I think the crossover point is somewhere in the 450-500 hp range, but it also depends on how high you want to rev your motor. I'd feel pretty good about 2 bolt mains to 6500. I'm sure they could handle 7K, it just becomes a matter of how long.

 

.....I paid $175....that was for standard 4 bolt caps. For splayed billet caps it would have been $325.

 

$700 is definately on the high side. But its easy to spend that much if you use top of the line billet caps.

I would rather have a 2-bolt-to-splayed 4 bolt conversion vs. a factory 4 bolt anyday since the splayed setup is stronger.

 

I also have a replacement motor from the dealer. This means 4-bolt right? Can the bottom end of these handle any higher RPM's than the 2-bolt? Just wondering for when I do a cam (down the road).

 

You can get a new LT1 4 Bolt Main Shortblock from Sallee Chevrolet in Oregon for $1695.....

 

I believe that I got the last one from Sallee, but maybe not. Give them a call.

 

The GM 4-bolt block is excellent for a high performance engine... you just need to add billet caps. George Baxter used the straight 4-bolt GM block for his 1,125HP 9.04-second LT1 setup. When the engine was torn down, it was in excellent shape, and the block is being reused in an 1,100HP nitrous setup. I wouldn't be so sure that a "splayed" setup is any stronger than the factory straight setup. Remember... the factory knew they were going to a 4-bolt design, and put the strength in the block to support the straight configuration.

 

$700 may not be as high as some think .

By the time you pay for a set of steel caps, buy $70 studs, pay for the few hrs labor/machinework, and then what most people forget - the ~$180-200 align bore...

Still, in the grand scheme of things, that isnt much $ IMO for some insurance if you're going to be making enough power to benifit from it .