ok you say it's probably a 4 bolt main since it was in a vette from the vin from my block, so why does my friend that helped me pull it keep telling me it's a 2 bolt main??? Is there any visual way to tell, So far I have the valve cover and oil pan pulled off. I am really wanting to know, cause people praise the 4 bolt mains over the 2 bolts. What is the difference in performance??

 

ok, look at the bottom of the block, you will see the crank and rods.......there are 5 main caps the main caps are what hold the crank in the engine,a engine with "4 bolt mains" will have 4 bolts holding from front to rear main caps #2,3,4...... kinda like this




. : : : .
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5 4 3 2 1

im not that great with a computer but that should pretty much explain it...... a 4 bolt main isnt realy neccery but its not bad to have it...

 

So there would be no way to convert the 2 bolt main to the 4 bolt main, I would have to buy an whole bottem end??? But that wouldn't be worth it. I'll take a look at the bottem of the engine and tell ya what a see.

Well looked got lost so my roommates digital cam comes to the rescue... I saw nothing of what you showed...

 

here is one side of it.

 

sorry I had to do this but I can't figure out the [img] [/img] deal, so I had to resort to this.

 

only way to tell is by pulling the oil pan and look at the main caps.. there are five rows of em, the ones of either end will have 2 bolts and the center 3 will have 4 bolts across.. really easy to tell just count.. cant really tell from that pic but it looks like like theres 4 bolts on those caps.. kinda hard to see from the side but it appears to be..

 

yup thats a 2-bolt

 

That's a 2 bolt block.

Here's what a factory 4 bolt main looks like.

 

ok well it's settled it's a 2 bolt main... So why do people perfer the 4 bolt over the 2 bolt when at the year my car was built it had the same amount of hp and torque???

I appreciate all the information... Thnx all, hopefully one day I will know what I am talking about when it comes to engines.

 

that is a 2 bolt main motor typical of late70 to early 80 vette and camaro engines, you can tell that it is , for that time period, a hi performance 350 because of the X rods (see the X on the connecting rod cap) that bottom end as long as its tight should be good for 6000 rpm..... im not saying in its state now it will turn that but im saying that set up (2 bolt mains x rods cast crank)its good up to 6000 rpm. same motor in my old z28.... dont let anyone tell you 2 bolts are no good, there perfectly fine unless your towing a 10000 lbs trailer or running 7000 rpm for long periods..... good luck with it!

 

k after lookin at the second pic i'd havta say its a 2 bolt.. an you could always get em splayed and have 4 bolt offset... stronger then a factory 4 bolt becasue its triangulated instead of linear.. kind of an unnessicary expensive to unless you plan to run a lot of spray or a power adder or somethin... not really nessicary at all on a street car.. my mains are splayed but only because i got the block with the machine work already done.. if it wasnt already done i wouldn't have bothered since its not really nessicary for what i did with it.. but its nice to know that its already there if i plan to go a little overboard with it in the future

 

another thing... make sure you pull the timing cover and check the chain and i would pull the camshaft because theres a 90% chance if its original its got some flat (worn out) lobes...

 

as for the cam I decided on the comp cam 268H to put in it, along with edelbrock Etec heads so that means I will have to change the intake mani, which I was looking at power plus cyclones vortech intake manifold, then with an edelbrock 700-750 carb, not sure which one to use yet, I think this is be the best set-up, for the engine as for having the hp (300-350+) range I want and the torque (380-420+) range that I want. or I could be dreaming alittle to big....

 

With that kind of power, you wont need a 4 bolt anyways. I wouldnt put one more minute of thought on the 2bolt vs. 4bolt

 

yep there's no need to spend money on a 4 bolt, you don't need it. better to spend the money on machine work and make sure everything is flat, round, true, square or whatever it's suspose to be.

 

yeah for what your doin with it a 2 bolt is just fine, put the money into the stuff you need, defently replace the timing set, have any machine work done it needs, dont waste money on things it doesnt (ie. boring it if all it needs is a hone) turn the crank have the rods checked out, and buy some new pistons and get rid of the junky ones that are in there.. a new timing set..spend the money making it reliable.. buy an arp bolt set.. should be pretty much overkill for what your doin but they're strong as hell and they'll give ya piece of mind. Also ask around on the boards about head/cam combos.. might be able to get a better combo (more power) for the same price or cheaper.. with the type of power goals you currently have in mind a set of reworked vortechs would work just fine and probably be lots cheaper..