Whats the difference in these blocks?

[87regal98formy]

OK i have a block from an 85 turbo car in the first picture. And the second picture is from my 87 gn im guessing an 87 block... My question is whats the difference in them besides the lifter valley being different? Any info on them would help thanks!
85 block

87 block??

 

[TURBOELKY]

85 = 14 bolt oil pan, no oil drain back in block, and I heard they are not as sturdy of a block

87 = 20 bolt pan, drain for oil, and are suppostu be stronger. is that how you spell suppostu? does'nt feel right

i'm sure somebody else will have something more scientific like nickle content, cadium, or something else wild like that.

 

[jasjamz]

the number of oil pan bolts, and the 85 does not have the oil return drain in the front of the block. Others may know more...
Edit:i knew someone was typing faster than me...LOL

 

[Just a Six??]

Nickel content is pretty equal from what I read. Deck height is a TINY bit different. Have one sitting here I may build for a project. Other than the oil mod not much difference.

 

[87regal98formy]

yea i did notice the oil drain back hole wasnt there. How do i get around that just get it drilled??

 

[my85grandnation]

Some 85 blocks were 20 bolt oil pans.

 

[turbodave231]

The 86-87 blocks (109's) have the head bolt threads sunk down deep along side the cylinders. When the head bolts are torqued, the deck surface does not distort. This helps distribute clamp load evenly on the gaskets.

The earlier blocks have the head bolt threads right up to the deck surface. With a thin wall stock casting, the deck surface will warp and cause gasket issues. Stage blocks have head bolt threads up to the deck surface but avoid this problem by providing a much thicker deck.

IMO. As far as stock blocks go, the 109 block is the better block to start with.

Dave

 

[charlief1]

The 109 block also has oiling changes. If you look at the right side of the oil gallery you'll notice it's moved over slightly for better oiling to the mains. It doesn't intersec the right lifter bank.

 

[49-blues]

Isnt the front cam journal also different -one has a groove and the other one doesnt? Need to use the proper bearings.

 

[Just a Six??]

Overall, for a 500-600 HP engine, it will work. But got to pay attention to a few small details. Usually you get the 20 bolt 85's for FREE compared to the 87 109. I happen to have a few cranks, some cheaper pistons, stock rods all sitting here so I just want to try one compared to my fully built JE Piston cryoed 109 & see how it holds up at 600 HP? Banning does it with a Non Turbo Crank as well in the mix. Just NO Detonation is the Key to it living!!
With Detonation under control, I dont see any big issues? 11's all day long.

 

[conn84gn]

The 84 front and rear cam bearing have a smaller outside diameter
inside ID are the same