I have just acquired another Camino - a 1979 GMC Diablo with factory installed 350. Is this engine likely to be a 4 bolt main engine? I may want to upgrade the power plant and a factory 4 bolter is certainly a good place to start.

Your thoughts????

THx,
Doug

Doug, I wouldn't think it would be a 4 bolt main block, but I could be wrong. There is no way that you can tell (numbers wise) if a block is 4 bolt mains or not. The only way would be if someone else had the same type Elky (GMC) with a 350 and they found out by pulling the pan...which is probably what you'll have to do if you wannna really be sure. But let me ask you this...if your going to upgrade (more hp) wouldn't you want to do a total rebuild anyway? If you pull the engine, and it's not a 4 bolt, you can get one (5.7 litre) from a boneyard out of a GM 3/4 or 1 ton pickup or a Surburban for about $150-$200 and it will be a 4 bolt if it's a 5.7! My advice would be to build another motor from start, that way you'll just swap in the newly rebuilt motor when it's completed and not be pressed into rushing things to get the car running right away...especially if you use your Elky daily. Money and Machine shops have a way with messing up the best made plans. If you really want to build a screammer, I would think that you would at least want a forged crank, if not the rods and pistons also. Take your time and do it right. You could also buy a 4 bolt main crate motor if money is not a factor. I prefer to build my own but that's just me.

The 4 bolt block is definitly prefered, it depends on how much power you're talking about,and how you're going to use it. I've built several strong (325-375 hp) street engines,350 and 400 cid using 2 bolt blocks with main studs. I haven't had one fail yet. Just keep the red line around 5500-6000. Think about it, how often do you rev a streeter over 5000 anyway.

...factory installed 350. Is this engine likely to be a 4 bolt main engine?
Hmmmmm... considering that the anemic 1979 LM1 350ci engine only put out a whopping 160HP I really doubt GM would have used a four bolt main block.

:mrgreen:

I may want to upgrade the power plant and a factory 4 bolter is certainly a good place to start.
You do have an alternative by using a 2 bolt main cap block and having your machine shop install splayed caps. Because the 2 additional bolts are at an angle into the meatier part of the block, they're suppose to be stronger that a traditional four bolt block: Splayed Main Caps (http://www.catpep.com/Products/BilletSteelMainBearingCap.htm)

Four bolt main blocks are desirable in high performance applications because the extra strength of the additional bolts keeps the bottom end rigid and less prone to failure. However, a properly prepared 2 bolt main engine will work just fine. Often times you'll lose a rod bolt before you break a crank because it's "only" a 2 bolt main. My $.02

:mrgreen:

...factory installed 350. Is this engine likely to be a 4 bolt main engine?
Hmmmmm... considering that the anemic 1979 LM1 350ci engine only put out a whopping 160HP I really doubt GM would have used a four bolt main block.

Very true! IIRC, the 4-bolt block was dropped from the car chassis line up well before '79 anyway. It still could be though, somebody may have swapped one in at some time. But like noted above, the numbers won't say, you'd need to pull the pan to know for sure.

One way to tell if it is a 4 bolt by the numbers (not 100%) is on the engine ID pad, located on the back of the drivers side block, close to the firewall, the numbers end in "010". I have found this fairly reliable.

... it will be a 4 bolt if it's a 5.7! ...

Not necessarily. Most 5.7s in Corvettes from then were 2 bolt mains. But you can still generate LOTS of secure and reliable power with'm! http://www.corvetteforum.net/c4/alchemist/thumb.gif

Alchemist, I think you may have misunderstood me. 3/4 and 1 ton trucks and Surburbans come with 4 bolt main blocks. We just picked up (Friday)a 1983 3/4 ton 5.7 (350) for $250, it's a 4bolt main block and also has a 400THD trans...ripout the engine and trans...and call the wrecker (gone by Monday) Best fun was when my kid beat my Elky with a $250 truck. Just like pulling whats left of the white meat off the turkey bones. Same deal with the 1985 pickup in the driveway...350 4 bolt main with a 400THD but we decided to keep the truck. I also bought a 350 motor from another ECC member about 2 weeks ago...it came out of a 1973 pickup and it's a 4bolt main. Thats 3 for 3...I'd say thats it's pretty good odds that you'll get a 350 4 bolt main block out of a 3/4 or 1 ton pickup. And if it's mid eighties or older it's probably attached to a 400THD trans if it's an automatic. Best part about all this is that you can find these trucks in every boneyard everywhere...and in most cases a lot of them. I'm tripping over them in my area. I can go to the closest boneyard to my home and know of at least 5 more 350 4bolt main blocks that are in trucks and untouched. Try to find a 350 2 or 4 bolt in any car...good luck. They've all gone to the crusher. Which is where all 3 of the 305s' I have will be going as soon as the 350 (383) motors are completed. Oh, by the way sometimes you get real lucky and find an old Surburban in a boneyard, and pop the hood and you may just find a 454 in it. 8)

Alchemist, I think you may have misunderstood me....

:oops: Oops...you're right! I did mis-read your 1st post! My bad! :oops: