wanting to use a 1979 mercruiser 260 block with the upper half of a 86 mercruiser 260

[chris0061]

I have a good bottom half of my 1979 mercruiser 260 and just picked up a 1986 Chris Craft with a rod thrown. Is there anything I should be aware of by putting that top half on the bottom half of the older engine. I do see the dip sticks are on opposite sides

 

[flipbro]

What do you mean by top half? I'm assuming heads and intake? 1986 was a transition year for the sbc from 2 piece rear main to 1 peice. If that's the case the flywheel and coupler bolt patern are different. But yes the heads and intake will bolt rite on too the 79 block. Dips tick location should not be an issue.

 

[chris0061]

So I just have to use the flywheel and coupler off the older engine correct?

 

[flipbro]

If the 86 has a 1 piece rear main then yes.Clean the heads up good and at the very least check them good 4 cracks around the exhaust valve. But I would suggest they go to a machine shop to be rebuilt. 30 year old heads if not rebuilt recently more then likely have worn valve guides the 0 rings are likely harden up and the umbrella over the exhaust valve has likely long broken up and went in the oil pan. That's just a couple Small things.

 

[kbsunlovers]

Deleted - should have read the OP's posting more closely.

 

[Scott Danforth]

your 86 is most likely a 1-piece rear seal. so no, the flywheel ( and most likely coupler) are different (and to some extent, the block) between the 1979 and 1986.
However if you have a flywheel and coupler on your older block, use those. any Gen 1 SBC head will bolt onto the block.

If it was me, I would probably build a new motor with vortec heads, etc.

 

[chris0061]

I have been thinking the same thing. Even looked at stroker kits. But do not know if I would need to match up heads with a stroker kit.

 

[flipbro]

What heads are you running now? As Scott said Vortec 906 or 062 heads work well u just need a different intake to run them..

 

[Scott Danforth]

Your heads have nothing to do with stroker kits unless you get a complete stroker rotating assembly. The heads affect the piston choice

If you decide to build a stroker, I suggest scat crank and rods, vortec heads, LCQ style pistons. Set the block for zero deck, shoot for 0.038-0.041" of quench height, and a comp cams XM270H cam and really makes some torque. Forged or cast steel is up to you for crank.

Budget about $2000-2500 if you do the assembly yourself.