I did a H/C swap on my 01 SS... Started fine but then it started losing power and sounded like the timing was off... So I tore it apart again retimed started it up again, sounded normal and drove strong for about 10min. Then it lost power and sounds out of time again. Tore it apart again and everything seems fine... Is it because of no tune yet? Mods: 243 heads, torquer v2,ported ls6 oil pump, ls2 timing chain,ls7 lifters, full bolt ons

 

it's not going to run well without a tune

 

Like mentioned above. A tune is definitely required.

 

Yes most likely because of no tune

 

Props on getting it to run 10 minutes. When I did my first cam the only way I could keep it running was to keep revving it.

 

ditto