Ok, the old L98 has officially crapped out on me. So I am thinking about either a new shortblock or rebuilding my old block. I was looking at the L31 shortblock. First of all would my old L98 heads work on this block or do I have to have vortec heads? If so would that engine with my heads(w/ 3 angle valve job and ported and polished), ZZ4 cam, stock TPI unit, headers, 3" cat-back, and free mods, be a good performance combo? Good enough for high 12's in a quarter mile? Any help would be MUCH appreciated, thanks!!

 

Hey,
the L31 shortblock will work fine with your heads or the vortec heads. they bolt on the same, they just use different intake manifolds.
You would be fine rebuilding your engine if it can be rebuilt. Unless you want new.
With either shortblock, the ZZ4 cam, stock tpi, stock heads with valve job, and a good exhaust,
I think you'd be in the mid thirteens @ around 98-102 if it runs good. Maybe a little better if your lucky.
If 12s are your goal you might want to look into a better set of heads, more aggressive cam, and an aftermarket or well-ported stock intake.
good luck

 

Check into the pistons in the L31...may be crappy dish-tops which aren't very good for performance. Flat-tops are where it's at.

Your old heads will bolt up to the L31 no problem, use new head bolts to avoid sealing issues.

Personally I'd find a reputable machine shop and get a quote for a rebuild before making the decision. Don't know what all "crapped out" on your L98 that might make it non-rebuildable, but assuming the block, crank, and rods are reuseable I'd consider this path.