I'm pretty new to the board and pretty new to camaros as well so I'm just looking for some information. Basically I bought a 1995 LT1 Camaro with about 149,000 miles on it for a decent price. It was a police car so it does have the B4C police package. Besides body work(dents... meh) it needs alot of engine work which I am more-less in the process of doing. When we stripped the motor down to the bare block I had a guy that runs a performance shop(dyno tuning, etc.) and deals primarily with Fbodies come and look at it and one of the first things he said when he checked out the block was, "holy sh*t dude... this is a 4 bolt main".

Well that meant nothing to me, but appearntly it's a good block to have. I'm sort of wondering what the value of the block is in comparison with a 2 bolt main. The block does need to be punched, no big deal, but can someone enlightmen on this 4 bolt main thing and how much it might be worth. Reason is I'm trying to figure out my plans for the car. I''m really only looking for the 300hp range, not a drag car or anything crazy and it will be naturally aspirated. I basically have an opportunity to exchange blocks with the guy that runs the performance shop(4 bolt for a 2 bolt thats already punched .40 over and some other "stuff"). Now being that I don't want crazy horsepower and such would it be better for me to keep this block that I have, do the machine work and get it put back together or just get the 2 bolt main and the "stuff" and call it even("stuff" willl prolly include rods and pistons, etc., dyno tuning, blah blah).

Sorry that's sort of alot to take in, if you want to just skip all the other stuff and skip to how much the 4bolt main is worth then thats fine too. I was told that the 4bolt main is the corvette block? And it's good to about 600hp?

 

4 bolt mains are stronger, and can handle alot. They also came from corvette motors, which is strange to see on a 95.

usually some 93's have them only.

Tim

 

I was surprised to see mine was a 4-bolt block. Found out when I changed the oil pump because of the famous pickup tube coming off.

 

I have read that after they stopped putting LT1's in at the factory in 1997, all GM factory replacement engines were 4 bolt main blocks, which as noted above were also used in Corvettes.

Four bolt main bearing caps are stronger beause you have four bolts instead of two at each point where the crankshaft is being held in the engine block itself. This makes for a more rigid base for heavy loads that the engine will endure in high horsepower applications.

The previous owner of my car replaced the long block with a GM Goodwrench crate motor that was built in 2000, so I think that I may have one as well, but there is no easy way to tell (that I know of) with the engine in the car.

Since you already have yours out, and know that you have a good basis to start from, get that sucker stroked, throw a forged 383 kit in there and spray away!

 

Something that bears repeating every once in a while...

All things being equal, 4-bolt mains are theoretically stronger than 2-bolt mains, but keep a few things in mind:

1) Having 4 bolt mains means that there are also two extra holes in your mains.

2) 4-bolt mains won't save you if your machine work is off. I would personally RATHER have a 2-bolt block that is properly line bored and studded, than a 4-bolt main factory block that has never been rebuilt.

3) A 2-bolt main block can be converted to a 4-bolt splayed setup, which is better than a 4-bolt parallel block. A 4-bolt parallel block could be also, but it's far more of a challenge.

4) I have personally owned 2-bolt Gen-I engines that, after a proper rebuild; made well over 500hp and 7500+ rpm, which is meant to illustrate that a well done bottom end is more critical than the number of bolts in your mains.


Now, having said all that, having a 4-bolt block is a GOOD thing, so be happy.
Just make sure that when you rebuild it that you don't "rest on your 4-bolt laurals". Do the proper machine work, including a line bore, decking and honing with torque plates. And by all means, use studs instead of bolts.

 

Well I'm not sure if I'm going to keep the 4 bolt honestly. I'm not going to be wanting crazy horsepower at all, so I'm not even sure if I will stroke it. I'm on a tight budget, but I don't want to go "ghetto fab" with this motor, it needs to be reliable above all else. No matter which block I go with it will be properly machined.

I'm sort of wondering what sort of dollar value can be placed on the block, knowing that it needs to be machined(the block needs punched due to some marks on the wall in cyl #8).

 

4-bolt mains were kept in stock for replacement shortblocks, however I think I may have gotten the last one. Cost me around 1600 bucks.