I have a main bearing going out on my LO5. Dad says it is so bad that the block is basically junk. Says its fixable, but might as well get another. When did chevy make roller blocks? I know the tbi roadmasters and vortec trucks are roller blocks. Any others I should know about?

 

I think they started in 87

 

Unless you have an exotic or expensive aftermarket block, it's not worth fixing an OEM block that has a spun main bearing. The webbing gets distorted from the heat so it needs to be line honed to make it all true again. The bearing cap also gets distorted from the heat so along with finding a new bearing cap, it would still need a line hone with a cap replacement.

Line honing the block moves the crankshaft slightly higher into the block. This means slightly less piston to valve clearance, shorter timing chain etc.

A damaged OEM block is scrap metal. Cheaper to find another block or engine than it is to repair it. The only time you would spend all the extra money to fix an OEM block is if you needed to maintain a rare numbers matching car. Then you do whatever it takes to keep the OEM parts even if it means spending way more to fix it than to buy replacement parts.

Now if you're like me, I have a $3000 Dart block in my race car. Actually it's my second one. The first one got damaged enough with a crack in the webbing above one of the crank journals that it wasn't repairable but I already had a bunch of previous repairs done to it from engine failures. Cylinder sleeves, line honing, etc. For the cost of a new aftermarket block plus machine shop work, repairs are cheaper until it becomes unrepairable like my first block.

 

87 up pretty much.A few were supposedly used in 86.Most car engines used roller cam from 87 up.Even the L05 truck engines used roller blocks,but,used flat tappet cams until 96.Some were completely machined,others may need some machine work such as drilling/tapping the bosses in the intake valley.#638 & #880 blocks will be roller blocks.

 

I have a 93 350 block. I bought it under the assumption it was roller as well. It is not. Doesn't have the provisions. It was a full short block with machine work done for $500. Be sure what you buy Atleast has the provisions such as lifter dog bone retainer humps. Good luck!

 

I didn't think any of the TBI trucks had roller cams/provisions...

 

Yes some did.Some were not completely machined,some were.They had flat tappet cams'but'a lot of the blocks were roller blocks.

 

What casting # does your block have?How are you determining that it's a 93 block?

 

Let me guess. The only way to tell the difference is the casting numbers.

 

I have pulled many TBI motors that were roller blocks I even pulled a 305 TBI in a 90-2? Camaro that had a factory roller cam in it.

 

Yes, I know the camaros did. But I need a 350 roller block. Any recommendations?

 

Strangely enough it was sold to me by my old shop foreman from his 93 k2500. Iirc the only designation it had was lg57. I'll try to see it tomorrow if possible. I was told tho that up to 95 is a crap shot. Some were equipped and some werent

 

Best bet is to find a #638 block or #880 block.The machining may not be completed but the provisions will be there.I've seen some that had the retainer bosses cast but not drilled.Some that were drilled but not tapped & some complete.

 

Every 1996-2000 L31 vortec engine is roller and pretty easy to find and cheap to get. Used in chevy/gmc trucks, vans, SUVs

 

Every 90s GM truck Vortec motor that I have had the intake off of(and that's a bunch) has been a roller block. I have converted a few of them to roller cam during overhaul by sourcing the dog bones and spider. I think I had to drill and tap one, others were already done.

 

I have seen plenty of 90s GM TBI trucks, vans and SUVs that had a block iirc casting number ended in "427" that do not even have the raised bosses for the lifter spider or the raised lifter bosses. 638" and 880" castings should have the bosses as everyone of them I have seen has them but no gurantee. I have a 1-piece rear seal 350 block out of a 90s 1500 TBI truck that has NONE of the bosses and lacked the raised lifter bosses.

My uncles 94 C1500 had a factory roller cam in it and I have run across numerous 305 and 350 vans and trucks in the wrecking yard with factory roller setups.

 

I just found one of the blocks I was talking about on Ebay. It is 4727" as the ending of the casting. 87+ block without roller provisions. The full casting number is 10054727, if you run across one it is very likely a non-roller block. I do not believe I have seen one that is a roller with that casting number.

http://www.ebay.com/itm/GM-5-7-350-sbc-Cylinder-block-10054727-/330031359719?pt=Motors_Car_Truck_Parts_Accessories&hash=item4cd766e6e7&vxp=mtr#ht_182wt_1362
http://www.ebay.com/itm/350-CHEVROLET-ENGINE-BLOCK-/171467421859?pt=Motors_Car_Truck_Parts_Accessories&hash=item27ec4138a3&vxp=mtr#ht_232wt_1124

 

I have one of those (long) blocks, 1 piece seal, no roller cam parts cast in it. Came from a 86 vet and has the 128 aluminum heads on it.