Advanced Induction heads

[Craig 94 TA GT]

Anyone have experience with these? Since the broken header bolt and constantly running rich, I finally decided that a head swap is coming soon.

My goals is simply to swap the new heads in, and keep the stock components. So they'd be with the stock cam, pistons, etc. I already have CC 1.6 RRs and valvetrain. In the future, when time for a rebuild, I'd definitely clean up the AI heads and use them again, along with a better cam (but it must be CA smog-II legal).

I already contacted AI, and they recommend that I get the fully ported 200 cc heads, since I'm going to use them in the future, after a rebuild. However, they really didn't tell me if it will hurt anything for now, with a stock cam. And I didn't hear if they would hurt in smog tests, versus the 185 cc heads. I'm sure that any set will be better than the current ones, that leak at the header/head flange. Also, the price difference between all 3 packages aren't that much.

Do you think it's worth it to get the fully ported heads on an interally stock motor that has to pass smog? Thanks in advance for your advice.

[Craig 94 TA GT]

After talking things over a few days with AI, it looks like the 200cc fully ported race heads would be ok. However, we have a slight problem - since I'll be using the stock cam, the springs they offer won't work well. Ron at AI really feels bad selling something where I'd have to replace the springs when time for a rebuild and new cam. So he's trying to look for something that's a good compromise - works with the stock cam, yet I don't have to upgrade them in the future, when getting a "hotter" emissions legal cam.

Any ideas on which springs to use? The only other thought I have is....I have 120k. If the motor lasts to 180k, or 200k, I think it would be time to clean the heads and replace the springs anyway. And I do know a cam is not an option without a rebuild - the last thing I need is my decently running daily driver to end up with a spun bearing

[Joe 1320]

I've found that the LT4 springs work well with stockish cams.

[FroSSty]

Comp cams
26915-16 Beehive Spring

A little pricey but worth it imho. A lot of the B-body guys use them and swear by them... plus, you can (although probably don't need to) swap springs from exhaust to intake when you change your cam.
Check out THIS thread over at the b-body forum for more info...

btw, I have heard a lot of good things about those heads.

[Craig 94 TA GT]

Thanks for your advice, guys. I currently have the LT4 springs on my heads, and am pleased with them. I suggested it to Ron though, and it sounded like he didn't favor them too well as a good "compromise." But no doubt, I think I'd take it for my application...safe, cheap, yet good for lift up to .525 or so.

He did also mention the 915 springs too. But he doesn't know if it will work well with the stock cam. It appears the guys on the b-body forum say so though. I'll discuss that with Ron when he gets back to me.

And I heard great things about these heads too....one was a 50 hp gain in the same setup (which is obviously a full race setup) over a "competitor's" fully ported head. They've got a great reputation

[FroSSty]

Yep, there are a lot of guys over there that use these springs on a stock cam and rockers. Most of them upgrade the rockers to the 1.6s at the same time, though. That will all depend on what cam you decide to run in the future...

[Craig 94 TA GT]

Thanks Greg - I think that, if anything, they will be slightly more pressure on the lifters, but they are somewhat new, Comp 850s with only around 8-10k. In fact, in a comparison, I'm seeing it's very close to the LT4s I'm running, when at max stock cam lift with 1.6 rockers, 0.490:
Spring----------26915---------LT4--------LT1
Seat press------105 lb--------100 lb------85 lb
Press @ .5 lift ---262 lb------~260 lb-------?
Spring rate------313 lb-------~330 lb-------?

The valvetrain is all ready: NSA 7/16" 1.6 rockers, guideplates, chromemoly pushrods....I just have to swap them from my current heads, to the new AI ones.

As far as the cam, I'd probably run something not much hotter than a CC305, in order to pass smog. Maybe something a bit more agressive, but nothing to jeopardize the emissions test.

[Craig 94 TA GT]

After speaking with Phil, he believes that the 185cc package is best for my application. He also said that he recommends I'd stick with the 918 spring over the 915. That does save me $300, and is good enough for a future 355 with an emissions cam.

So I just had my core shipped off, and hopefully it will be ok.

[EDIT] Forgot to mention why they reommend those springs. Mainly because the valves are a bit heavier, being stainless....so he said he does not recommend anything less than the 918s. He said they should be ok on a stock cam, especially since I'm only going up to .490 lift with the 1.6 ratio. Ron and Phil are really great guys - very knowledgable and friendly.

[FroSSty]

I think the 918s will work good for you too. I forgot about those ones... Definately better for heavier valves. A friend of mine is running these springs with Titanium retainers. Talk about expensive retainers...