So my 396 Impala SS has been sitting in hibernation much longer than I care to admit. I finally made the move to get her back on the road and have some fun again. Trying to get back on the road on somewhat of a budget, and by that I mean I would like to use one of the options already in my collection.

Specs on the short block are as follows:
3.875 Cola Forged Crank
6.0 Oliver Billet Rods
Oliver Billet factory 4 bolt mains
JE Flat tops w 5cc valve reliefs
Pistons are sitting .005 in the hole.

So, my last go round, my build was EXTREMELY mild, and it worked fine. Stock LT4 castings with a anemic 218/228 (or so, been WAY too long to remember these specs) cam.

Now I've got the engine tore down, and I'm at a bit of a crossroad. Where to go with the heads now. Along the way, about 7 years ago, I picked up a set of pre-eliminator AFR 210 58cc LTx heads.

So...budget and performance/$$$ spent, what should I do? All options will include matching cam and ported LT4 intake. I am listing these options based what I am finding it will cost to get back up and running (just in the heads).

1) Run the AFR's as they sit. Remember, these are pre-eliminator heads. Can't find much on the performance side of these anymore. (Free.99) 11.26:1 static compression ratio.

2) Sell the AFR's, port the LT4's. (~$500 investment after sale of AFR's) 11.8:1 static compression ratio

3) Send the AFR's off to be cleaned up. I am told there really isn't a ton of extra work that can be done to these other than a clean-up, so I have no idea what the payoff will be. ($750) 11.01:1-11.26:1 static compression ratio (depending on cleanup)


I know the AFR's have gotten a mixed review over the years. I'm looking at them now as a sunk cost, so I don't really care what they DID cost me. Casting for casting, which is the better route at this point?

 

I think your CR calcs are off.
I'm seeing 12.2 with those 58cc heads and a .038" gasket. I'd actually run an .029" Impala gasket.

What are your objectives for this? Sticking with the stock PCM and the ~7000-7100 rev limit?
If you want a foolproof recipe for 450 rwhp SAE, sell both of those sets of heads, get AI200cc ported stockers and something around a 242 dur cam from them.
If you'll be happy with 400 rwhp, then I'm almost willing to say you could run with either of your current heads as-is and achieve that (I'd put better odds on the AFR heads). Just get a custom spec'd cam from AI or LE.

 

Hmm, you are right, I re-ran the numbers and coming up with 12.5:1 using the Impala gasket. Not sure what I keyed in last night, it was late... I'll revise my original post.

I am staying with the stock PCM, so 7000 is my absolute max. I'd love to hit 450, but if I fall a bit short, I'm ok with that at this point.

So what is it about the 200cc LT1 heads that make them better than having the LT4's opened up to 215cc? Just cost/hp? Can the LT4's potentially make a smidgen more? I don't have a set of LT1 heads to send off, so I'd have the cost of tracking down a set of them, or I can send off these LT4's...

 

I hope this is not against the rules.

http://advancedinduction.com/LTX/AiLTxLT4CompHead.php

 

That is one of the options I am looking at, but if I keep my quench tight, I am still looking at 12.2:1 static CR based on the largest combustion chamber available of 60cc. I'm sure that is more than fine for a light street/strip Camaro, but I'm not sure I can do that in a big boat and cruise in traffic (not a DD, but...). Plus in Arizona I can only get 91 at the pump (besides race 100). E85 was an option that was thrown out, which I could swing with some fuel upgrades. The E85 would help keep the cam a little smaller since the E85 would allow for a higher DCR and not detonate. I don't really want the need to spec a cam that is so big that I need a 4000+ stall and 4.10's...

The TS215cc from LE or AI would offer me 63cc chambers and get the SCR down to 11.75:1, which is much more doable for me.