chimingel

I bought a 99 ls1 from a ws6 ta and I think they have 853 casting numbers on them. Are they worth taking the time to port them or should I start with a different head. (I'm not 100% sure on the casting # it is 8xx the motor is at my shop and im trying to remember off the top of my head)

Studytime

iTrader: (15)

It doesn't matter. The differences are small. Your heads (sand cast) are not as accurate as the semi-permanent mold castings that were used on the '01 & '02 cars, but once you port them it doesn't matter.

So, those castings are fine for a full port job.

Good luck!
Ben T.

chimingel

Thanks for the info.

'Trust'

iTrader: (24)

I'd say that a set of 241's would be better to port, and you can get them cheap. 853's tend to have thinner walls and the air flow angles arent as good.