well people keep putting bigger cams in and making more power with the 346's all else being equal it should be the same with your cam. The cam in your initial post is the same one I have and it is pretty streetable, not much surging and the idle is not even that rough, for power though I vote go bigger

That one that 383 was selling may be the ticket who knows.

246/250 .632 111+4
12.5:1 CR
FMS cam


Vince on her has a similar cam and he puts down really good numbers but his heads kick *** too.

 

It sounds like your head porter is trying to compensate for not being able to make the heads flow well over .550". Having the heads flow well above .550" is not going to hurt the springs. You need to let him know that in the LS-1 world, it's hard to even find a cam with less than .550 lift. He is correct on the 112 LSA for nitrous though. I've always had the best results with the 112. I'm actually using a 111 LSA on the spray now, but I haven't tested it yet. The cam in your initial postwould be the way to go, but I would get it on the XE-R lobes. The other cam 383ss listed sounds like it would be sweet though. You can't go wrong with a Futral grind.

 

What he was saying is it's useless to get a cam with more than .550 lift because these head's best flow is around .500. He is somewhat new to the LS1 performance world, but has a lot more experience than me (he's been a performance engine mechanic for at least 20 years).

 

I have a 246 248 .613 .615 114 in my 382 with 11.3:1 and it doesn't idle much worse than my old 346 with a tr224 112.

 

I DON'T daily drive my car, but the 408 im building right now is going to have a 232/236 .6xx/.6xx lift 114 LSA cam in it sometimes BIG isn't always better the motor is being topped off with TEA Stage 3 AFR's though IMHO if you dont skimp on the heads: you can afford to go pretty small on the cam and STILL put out great power.

 

I'm going with a 248/254 615/613 113lsa for my 408. When you start getting into the .630 lift area, you are tempting your needle bearings to come out of your stock rockers.

As the others have said, make sure you have some high flowing heads if you plan on that big of a lift, or it will be useless.