Yep, another long post...



As I was having lunch with one of our local customers he mentioned something about wishing he could make 550-580hp or so with an LT1 casting. When I mentioned that it'd be doable he demanded to know why the heck I didn't sell him something like that...

So out of curiosity, I'm wondering what sort of interest there would be for an LT1 head like this...

Your typical fully ported head may break into the 26X peak cfm range with midlift #'s around 18X @ .300." I've had a slew of "270-285" peak cfm heads from most everyone, but even on a 4.060 bore I've never had any actually do that - the best peaked at an honest 264cfm. Most of this is simply people wanting to play flowbench games, and we try to avoid that as best we can, but for what it's worth, all of our measurements are taken on a fully computer controlled (which also handles all of the data acquisition) Superflow bench. We use a standard 1/2" inlet radius, and no exhaust extension/pipe of any kind for the #'s given to the public. Additionally our heads are centered over the bores accurately each time locating off of the bolt holes, so as not to skew our results by "inadvertently" unshrouding the intake etc. As a point of reference, the stock displacement HR packages we've done that have made up to 440rwhp (SAE) have been done with a head that simply flows an honest 270-273 peak cfm (on a 4.030" bore) with an emphasis on our .300-.500 #'s. Of course with a cam in the 23X int. range you can make ~450-460 hp (around 400rw w/ a manual) all day long with a 25Xpeak cfm head if the midlift #'s are there. Our "full port" casting is actually leaving a good bit of material in the head, as we simply don't feel it's safe to push the casting as far as some do & give that to normal customers, so we only make the port as large as we have to, to meet whatever goals.


That's just a little background... On to the actual point of this post

Would there be interest in a more race oriented LT1 casting that should be capable of making 460-490rwhp or so, SAE corrected? As with anything, there is no free lunch, and this would be oriented towards guys who's cars were primarily toys/weekend cruisers, and wouldn't mind some maintenance every 10,000 miles or so. For some that'd be every 6mos, and this honestly isn't something we'd want to sell in that case, but for others who only put 5-6,000 on their car a year, maintenance like that may not be too big a deal.

We're actually close to where we want to be flow-wise & dimension wise with a small valve that wouldn't require the seats to be removed, though that would be an option. For standard bore sizes however, we don't like running too large a valve, just because it flows well on our bench, so we're hoping to stay with a 2.00" valve. As far as actual flow #'s @ 28" H2O, we're looking at something a little better than most fully ported LT4 heads do on our bench, and though I don't want to publically release any at this point, flowbench games aren't something we're into. If any serious person wanted to see in person that we were getting the #'s prior to purchasing, then we'll be more than happy to have them over to our facility where we can go over test setup/procedures and perform the actual test in their presence (or even let them do it LOL).

For some, an AFR would be the better choice obviously, but for others who want to stick with a stock casting for whatever reason (class rules, wanting a stock appearing setup for street etc.), doing something like this might be a viable option. Additionally, as nice as AFR castings are, they're almost perpetually backordered, adding at least 8weeks to what could be turned around in as little as 4days.

Most any well ported AFR is going to end up costing approximately $3k with quality components, and this would likely end up in this approximate range with a worked over intake manifold. Do you guys have any suggestions or comments regarding if LTx guys would actually be into something like this? It wouldn't be cheap, especially when quality valvetrain components were added, but we'd like to put more of what we've learned in our race products into our high-end street packages.

So... suggestions, comments, etc., please let us know . Posting is probably best at this point, as I handle all of the email and have been absolutely inundated with questions regarding the ongoing group purchase.

We'd greatly appreciate any feedback however, before we spend more time developing an actual package for something like this .

Thanks so much,

-Phil

 

Define "maintanence".

Do you mean new valve springs or new springs and lifters?

 

I think that I already have the heads to produce that kind of power...I just need the rest of the package. I'll probably be e-mailing you in a couple of months for some intake & cam advise. Good Luck

 

Aye, Phils knows what I think....

 

I maybe interested down the road a couple months if I don't go with a big Vortech or Procharger. What you are saying is I send in a stock set of LT1 heads and intake then $2,500-3k later I get a set of killer LTX heads that flow close to 300cfm and an intake to support 490-500rwhp. What will this include? Valves, springs, cam everyhting or what? LMK Later Clint

 

I think what most people on here are for is maximum HP. So yes if you guys could offer a 450rwhp+ LT1 topend package (potential) I would imagine the response on the consumer side would be HUGE. But personally for me, I would wayyy rather have 450rwhp instead of 420rwhp but my main concern is durability. I don't want to change valve springs and lifters every 5-10k. If you could come up with something closer to a 20k interval that might help a little. Just a thought anyway

 

If all you want is 420 reliable everyday rwhp, Phil's got you covered there as well. No worries on that, man.

 

I think i would put the money into a AFR head, something like a 210, with matching LT4 intake, and a very wilded HR cam....

 

What is a ballpark figure on cost?

The 460-490rwhp figure, is that for a stock bottom end n/a? If so how are you planning on that when the best afr stock bottom end car n/a is only at 452rwhp?

I gather this will be setup for a solid roller, correct? What c/r area are you looking at these packages running?

 

I'm assuming race oreinted being AFR s ,not lt1 castings....and even still using afr's to achieve 490 rwhp+ it would take a very good shop vac to suck up all those shavings once the head comes off the milling machine,unless ofcourse we're talking a built bottom end which in that case thats cake

solid roller,high comp. might get it there if we're talking
with a stock bottom end..but everything would have to be addressed from induction to exaust which makes that 3g closer to 5g... high reving stock bottom end 6900would be the limit for a stock rod..there again unless we're talking a built short block..which as i said changes everything,,

 

"Maintenance" would depend on the individual setup. Where someone was after results with a HR cam, that'd entail swapping springs. How often that was would depend on what spring they ran in the first place, so it'd be up to the customer really.

This really isnt geared towards people who want to drive their cars daily. How many race engines go 1000+ miles, much less 10-20k without being torn apart? This would be something geared towards the guy who has another car, and by the time ~1.5-2yrs had passed, he'd be wanting to change something in his setup anyway. Optimally, we'd have the topend back in our hands every 10-12k to inspect, etc. Of course how long all of this lasts will depend on cycles... if you run around at 4000+rpm every time you're in the car, you'll obviously tax wear items (springs) in fewer miles. Essentially we're thinking of a 'basic' race port package, with options for lighter valves etc.

Jeremy, for alot of guys, that'd probably be the easier route, some of us just like to make things difficult

Ken, I'm talking about #'s off of an industry standard dynojet so that we can compare the results with other real world results. The shortblock isn't really going to make much difference when it comes to making power anyhow (provided it stays together), but fwiw I'm talking about GM castings. I would hope that most would realize making this sort of power on a stock shortblock isn't worth risking an expensive topend IMO - other's will probably disagree & I'd certainly like to see what would happen & how long it'd last

As far as RPM requirements, the limit of the stock PCM is what we'd have to work within in most cases. In other cases for a few hundred more RPM, I'm sure people will pick up dfi or fast. Either way we're not talking about exotic valvetrain components (unless someone wanted to push it that far) etc., simply a well engineered combination of parts

Compression ratio will obviously be limited by whatever fuel the customer needs to run. I know some crazies with drums of fuel for street cars in their garage, but if you have to run pump fuel, then there's not much we can do aside from work around that constraint

This won't be a package for the faint of heart, or your average guy. It should handle a surprising amount of cycles/miles, as our cams aren't really that aggressive - we rely on a better port in most cases as opposed to more camshaft. Both would have to be produced/spec'd optimally to meet whatever goals the customer had. If they wanted 450 sae rwhp, then they'd require something different from the guy wanting 470rwhp, as at these levels that's a pretty sizeable difference. We're simply trying to apply what we've learned on the race track to the street, making compromises for durability/safety where necessary.

At any rate, we're just wondering if there's reason enough for us to push forward with more development in this particular area at this point & later we'll iron out the details for a few packages from HR/normal rpm to SR & higher rpm & most anywhere in between

Thanks for the questions thus far, it helps give us an idea of what direction we need to steer towards.

-Phil

 

Phil, IMO i think you guys should go for it anyway! regaurdless of customer interest
hell companies like Cartech, MTI etc. have been pushing the LS1 stock bottom end numbers thru the roof lately, 490/500+rwhp with H+C cars....

try it on your car (or whomevers) and the interest will fall into place once the proof has been layed out
go for it man push that envelope!

Steve

 

I'll pony up for a test vehicle...Russ and I can see what the part can do!

You supply the parts and I will supply the motor and labor.

 

I'd like to see the setup on an LT1 once its done. I would move ahead no matter what people say.

 

Hey I going to call you and ask about getting 450+rwhp out of a 357 with stock LT1/LT4 castings with a HR cam. But I really want 420+ foot pounds of torque. I'm all for this. A 350/355 for the street won't need AFR castings. As for maintenance I wouldn't mind changing springs every 10000 miles. But would this be necessary on a HR setup, especially if you're running a rev kit