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As mentioned, you'll be better off porting the heads you've got. Personally I wouldn't upgrade from -1's to -13's I'd go for at least B1-MC's.
Again this has been mentioned but, you will need new pistons as the valve reliefs are bigger and in a different place, also I'm not sure if the headers will swop over either, the -13's are cut back some along the exhaust side face. Also you would be better off going to the 3X intake as the others don't seem to have a lot of material to match the roof of the intake port. For the gains I'm not sure it's worth it.
If and when I get round to upgrading, B1-PSO's will be on the top of the list.



I have a set of tti 2 1/8 step headers bolted to my motor now fit the same as the 2 inch I had on the -1's. I too would just port out the -1's If I were him. Only reason I upgraded to these was it was the biggest head I could fit under the stock heed with no scoop and use off the shelf headers. Modern cut the exhaust exits the same as the -1's not like indy does so I could use the headers I wanted. I would have gone with a b-1 head but it would not have cleared my factory hood.