Heads for a stroker?
 

I have a 95 trans am with an LT1 383 stroker, it just has the 194 heads on it with 1.6 crane came roller rockers and comp cam springs now, but i am looking to buy new heads this winter to unlock some HP, i am looking for some suggestions on whats available today to get the most performance out of this 383 and also if my valve springs and rockers are going to be usable or if ill have to buy new. thanx

If i were you i would call Lloyd Elliott

http://www.elliottsportworks.com/

I called him a few months ago (real friendly guy) told him my plans he told me what tould be best for what i want and now im on a save up plan. give him a call

How much do you have to throw at this?

383s/396s can take plenty of port/cam and maintain decent vacuum.

Lloyd;s a good place to go with LT1 castings... but I bet he could do some serious work with AFR 220's or some 18* heads (if you have the cash/urge to replace the heads/intake/headers/pistons).

Having seen what max-port/valving can do in LT1 castings, I hesitate to push the AFR/Dart heads options... but they're there if you plan on going big.

I wrestled with the same thing a few months back.
Although the LE2/LE3 (or AI equivalent) would likely have worked ok, I felt that ported
set of Dart (or TFS) castings would provide much needed flow at the top end.
I ended up with 211cc and 299cfm@.600 using 2.055"/1.600" valves, which I feel is just
right for my 383 using a rather aggressive H/R cam. A milder setup would probably be
more likely to get away with ported stockers.

Is 3cc and 19cfm worth an extra $300? I suppose that depends on your application.
In the grand scheme of a $12000 build, I wasn't about to let stock castings end up being my bottleneck.

FWIW, the difference between LE2 and LE3 is $250, and only nets you an increase of 3cc and 5cfm.
But also supports 10hp more than LE2s.

I think the point is that if you have already invested in a custom cam (mid 230/240 or better), good springs, CM retainers and
larger valves, aftermarket castings are the next step. Not the other way around.

If you're building an extreme S/R monster, ported 227 castings may be more appropriate.
I'm not a fan of AFRs out of the box, but with some milling, a little portwork and a good valve job,
they can be made to put out some serious performance numbers.

Shamelessly ripped from Dart's site (for reference)

http://www.dartheads.com/ftp/Article...ze%20chart.jpg

James, those are flywheel hp numbers? Please correct me if I'm wrong, and thanks for posting that up.

That is my assumption based on the numbers provided.

That chart is a good follow-up to a older thread I was reading the other day regarding port velocity
and it's significance towards filling the cylinder efficiently.

just an FYI advanced induction stock castings are only 200cc, flow 288cfm@.600 and have a mere 2.00/1.56 valve. without looking at the entire curve and adding the advantage of the small factory chamber for efficiency. 11cc less volume, a small drop in peak cfm yet a way smaller valve, im willing to bet the stock casting will make more power and tq under the curve then those darts, maybe down a few hp at the peak only over the head you posted. but avg numbers would be up. just my opinion, unless you really plan on feeding it compression and cam and revs, the ported stockers are better then most want to believe, it leaves the options open for the original poster.

For comparison purposes, AFR makes both a 210cc and a 227cc (used to be called a 225cc I belive) head. Those are likely the only 2 AFR heads I'd consider if I decided porting LT1 castings just wasn't going to work. Both AFR castings require the LT4 intake manifold BTW.

The Trickflow seems to be in noman's land unless you're looking for thick decks and lower compression for boosted applications... but if that's the case then you'll probably be looking at the Dart CNC'd Pro1's anyway. With a 66cc chamber, the Darts CNC'd may be too large for NA guys looking for higher DCR without requiring a piston dome.

For N/A your best bet is a serious porting/valve job on stock castings or better yet, ported AFRs. I wouldn't run stock AFRs any sooner than I would stock LT1 castings, so the difference between AFR and LT1 set ups is pretty substancial for minimal gain.

Obviously the idea is to match the airflow numbers with the engine size and cam selection... but I think it's worth pointing out the ultimate fudge factor here is variable air-flow-bench numbers/calibration... and even worse, the correlation variations between air flow charts and actual engine hp. Lower flow numbers with even the same cam and displacement can vary hp levels in two cars of different weights (which affects the load on the engine and acceleration...). You may have a lower tq/hp engine on the engien stand, but in a lighter car the engine may respond with more hp on the dyno (something to do with swirlpatterns/harmonics/all that jazz varrying between different porting patterns and perhaps a longer/shorter cylinder stroke).

Personally, I just call my engine builder, tell him what I'm looking for and follow the shopping list he gives me.

Full Disclosure: After having a shop screw up my 396 bottom-end in more ways than 1, I had the local hot machine shop fix it up and had a local engine builder select and assemble a pretty excessive 396 build (from a durability standpoint... I wouldn't call it a max-effort engine though). Even with this one, initally dyno'd through a stock TB, mid-length headers, and stock ignition/opti we used some twice reworked LT1 heads and found ~320ft pounds from 2000rpms to red line. Things have changed since then, including a monoblade and some other mods still in the works... but I won't be dyno'ing it until we've got it properly set up and tuned with LS1 coils, a custom cam, and a small nitrous shot (I'm thinking ~150 is plenty). It was about 420rwhp through those LT1 castings on a GM hydralic roller cam... hoping for ~440 with a smoother idle once the coils and monoblade are all worked out... add in a custom cam 450 wouldn't be unreasonable IMO. I kind of lucked into the heads I'm using, but having done it once I know I would have made the same decision.

Steve, I like the part about finding a builder that knows what he's doing, and have him choose the parts for the application at hand. Not knowing enough myself, I would go that route. Correct parts selection means to much to the performance of the car. If you do it yourself or aren't copying someone else's set-up, disappointment might be the end result.

Amen. This isn't the time/place for bleeding-edge research. Many successful LT1 combinations have been used in the past and some LSx and SBC tricks can also be incorporated... but I hesitate suggesting any high-risk options (like 18* or 11* valve angles, race-gas-only DCRs, or ultra-light rods/pistons/cranks, etc...) there are ways to make an engine more DURABLE without sacrificing hp (although maybe some cash)... for a street build I think its important to keep things in perspective.