Thread: 2bolt main to 4bolt main

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I have a 70's 454 with 2 bolt mains, and i wanna change it to 4 bolt mains. are there conversion kits out there? if so where can i find them? or is this more trouble than its worth.
thanks

There are several suppliers of steel 4-bolt caps. But, unless you plan on using this motor in a SERIOUS Drag car, we're talking Funny Car/ Altered fuel burners. The costs are just not worth it. A set on main cap studs will give you all the strength needed.

Aside from the cost of the caps. You will have labor costs in the fitting/milling of the caps and the final line bore/hone of block.

Thanks

how much hp are you making ? here are some things to think about a new line bore this will move crank.005 or more to the cam and if this has been done to your two bolt .re fitted with 4 bolts it will have to be done again .005you can get timing sets for this but with this they so much 0.10 you can use gm caps but they will have to be fitted to block they not just drop in thing s like side crush so cap will not walk drilling to two holes in the main web of block this dose not help if you go to deep you will hit oil you gm rear cap will the thrust line up ?with block if not done rigth end play can be good or not not fun to fix s i have not seen to many times on a big block where you need it . they are better places to spend money you can make 600 hp all day long with 2 bolt mains and 3/8 rods this is gm best block in stock form i built many seen them go to7000rpm with two mains 3/8 rods mud trucks 7500rpm two mains pull truck 7500+ two bolt main and i can go on they call them rats they are hard to kill !!

Not necessarily, I've heard that 2 bolt main is plenty on that BB chevy motor. Only in some really ,really radical circumstances is in necc to go to 4 bolt. Those blocks are STOUT!

Sometimes, the 2 bolt blocks are even more desirable than a 4 bolt block because of the conversions. There is generally no difference between a 2 bolt and 4 bolt block except that the extra holes were drilled, so it is very possible to convert a 2 bolt block to a 4 bolt by drilling and tapping the extra holes. You can drill and tap the holes at an angle for splayed caps, which makes the block even tougher than a standard 4 bolt block. I wouldn't worry about that kind of toughness unless I was running 7500 rpm plus on a standard motor or 6000+ on a stroker.

The nickel content of the block is what is different here,,,,most blocks from the mid sixties and on,,,,they cheaped out on the nickel content,,which makes iron harder,,,,,four bolt mains where the cheap way out for the car company's to sattisfy the power market.
Old two bolt main blocks where Way Stronger,,,than even newer blocks with four bolt mains.
it used to be that we could tell what the motor came out off by the difference,,,four bolt setups where usualy from trucks.

You would spend wayyyyy more getting that done than you would to buy a 4 bolt block....and besides, as mentioned here, it's not necessary, the 2 bolts are plenty strong enough.

If you have a 2-bolt main block and want some extra strength and not the added cost....

Have the machine shop "pin the caps" This will make a 2 bolt bottom end stronger than a "stock" 4bolt main.

If done right they will use pins like the ones used on the deck surface to align the head ( on a big block) This works nicely on big or small blocks....