I appreciate all the debate and so forth. Very interesting topics. I was hoping to get some opinions on these items though:

1. AFR heads - likely increase in power with my existing camshaft. May lose some low end torque? According to Comp's Camquest software this engine is in the neighborhood of 450 Ft/lbs at 2500 RPM. Of course I can't see any of that on the dyno due to the stall speed of the converter through the peak torque range.

2 Procharger - this will likely put it into the 600 HP neighborhood.

3. Both? Other than the obvious advantages in pulling heat out of the combustion chamber under boost.... what's likely to be the benefit of AFR heads with 10 psi? In the import world we really don't worry much about porting or aftermarket heads - we just shove air through them with boost and in our experience tons of head work is usually wasted effort for relatively little gain. If we need more power it's just much easier to get a bigger turbo and throw more fuel at it. Of course they all already have pretty decent modern head designs.

GD

 

350, Comp Nitrous 274/288 cam. 9.7 compression. LINK G4-X management running a stock (Davis Unified) small cap and matching coil.

GD

 

more power na is more power under boost. Same pulley may make 15 psi on a small head and 10 psi ona larger head due to less restriction. Could make more power at less boost and lower intake air temps

depends what you want to do, how much power etc. if good intercooling, boost doesnt scare me. But given the choice i go less boost more head/cam to make the power i want.

If its already near 400 flywheel and you want 600, i’d try boost only. 10 psi can really wake it up.

 

I think a procharger targeting about 500 at the rear wheels maybe the best next step.

I think even at that power level I will be mildly worried about driving over my crankshaft. That's near 600 crank and this is a 97 2-bolt Vortec block with 177k on it. Good machine work and assembly and it's very clean inside - wasn't a spec of rust in jackets. I purposely didn't bore it to avoid needlessly removing material in case of boost.

GD

 

A similar aftermarket tpi on a afr 195 headed 383 with a 224 xfi lobe cam made 530 whp in a 5 spd car on just 8 psi. D1 procharger. Be close to 500 in an auto on 9 maybe 10 i think

 

im wondering what ours is going to make being its a 383 113 heads flowed 250 cfm lpe219 cam by lingenfelter the First performance intake witgh the bigger flowing TB intake flows over 1000 cfm.. 36lb injectors, holley Dual sync dist..holley HP efi sysem...im hoping at least 350 rwhp...

 

.

 

It's going to depend entirely on how well those heads were ported and how that matches the cam because in stock form they weren't that great (worse than the Vortec) with an outdated chamber design. Compression would really want to be a bit higher with aluminium heads I should think. I'm at 9.7 and have no problem with 32 degrees on iron heads but I do also have ideal quench on a Vortec chamber..... I should think those 113's should be in the 10.5 neighborhood with that decent sized cam.

GD

 

These heads were done by tpis they flow 250 cfm..if you look lingenfelter used these on there 383 builds with his matched cam the lpe219 ..560 lift compression is around 10.0 I was told they actually flow good..

 

I was looking for specs on the LPE219 and the most I could find was:
219/219 duration
.525/.525 lift w/1.5
.560/.560 lift w/1.6
112 LSA
Any idea what the advertised numbers are?

 

I saw 280/280 on some forum posts. Seems to jive with the duration @ 50 being equal.

GD

 

Yes duration is 280 280 we used a 1.6 rocker

 

I saw alot of good ETs with that cam

 

280 advertised with a 219@ .050" ?
That's pretty intense. Comps XFI280 has 230@.050.

 

Lpe was a good stable lobe, older profile. Alot of newer stuff out, 280 advertised should be in the 226-232 range at .050

 

​​​​​​That's what I was thinking. 280 adv. and 219@.050 doesn't seem to jive.

 

Hot cam lt4 was 279/219 they say.

Old comp magnum is 280/224 with same .560” lift as lpe, but depending on base circle and such, it could vary a few degs so the lpe could be very similar to the comp magnum lobes which do ok and are stable with moderate springs.

The xfi and faster stuff needs alot more spring

 

Why did the lpe have a 280 duration and only 219 @ .050 or was that a lie and its actually a little bigger?

 

From the info on LPE's website, the 219 is legit. There are no posted advertised specs. I can't say where the 280 comes from. If that were true it's a quicker line than anything Jones has to offer or COMP. In as much as I can tell anyway.
219@.050 falls more in line with something in the low 270's. My XFI intake lobe was 224/276.
Lobe lift I think is about the same.

 

Ok got ya should perform ok...i know it wont have a crazy lope sound...ive only heard one on youtube sounded pretty good tho...

 

This is interesting but I think it scrapes over the purpose of the design and its intentions. I would think virtually any racer who makes an engine will want the highest attainable output possible from that engine and in turn make the powertrain (converter, gearing) fit around the engine not the other way around. Vizard places huge amounts of weight on LSA based on reading what he says because it affects not only peak output but average output as well. It's important to realize that there's limits to the utility of a wide power band and sometimes it's better to be "peaky." I dabbled in the math around this at a point and here's something I wrote on The Turbo Forums that I consider applicable here:


The question in my mind is this software optimized to generate the highest peak output or the highest average output? If the former then yes I could see it being an application for a dyno queen or specific racing applications (close ratio gearing to maintain low RPM drop between shifts, loose converters etc.) vs a high average output with a good peak which would allow a wider gearing in the transmission and be more usable to the average person for a variety of workloads. It's also why at some level I droppeed my infatuation with the idea of making a variable runner length intake; It just doesn't really make as much sense if you're WOT and can stay in the torque running from gear to gear.

It all boils down to the simple truth that if you don't optimize the powertrain to your setup you'll never meet the potential of an engine. Anything else is a compromise, and engineering is the art of compromise. It may be emissions, mpg, mannerisms, the ability to tune it easily via EFI, the ability to run vacuum brakes, cost, temperature control, physical engine foot print or a myriad of other things I'm neglecting. It's why I'm shopping for 4.30 maybe 4.56 gears for my Astro Van. Yeah that may seem silly until you realize that I'm trying to gear it based on what I think it will do in a quarter mile which while not my primary purpose is something I don't consider problematic considering its average trip length and OD transmission.

I will also say the OP's build is excellent in terms of making a car you could drive on the street every day, get into a bit of trouble and have some fun with. If I were going to the next step (and my ring gap was wide enough) I'd look into bumping fuel into E85 and throwing some boost at it. Maybe even just pump gas +boost. I bet the results would be just fine. The results would probably be excellent even without AFR Heads although they wouldn't hurt by any means.

 

its not quick. Its lazy. Opening 280 to 219 at .050 is slow. Ramp is not steep. Xfi is much quicker

 

Are you saying that if I go from 280 to 219 in .044" (280@.006" to 219@.050") it's slower? Compared to (as an example) 280@.006 to 224@.050"?
The LPE covered 71 degrees in .046" compared to 56 degrees in the same distance. Any XFI I've examined, or Jones' quick lobes always have a tight spread between adv and .050".
What am I missing?

 

That's my thinking however any cam recommendation I've received always castrates the output because they're working with the application. Jones did exactly that with my request. I asked for this, he said that. I could see what the result was. A broader flatter curve. Then I asked again and put more emphasis on best output and the answer came back to something more in line with Vizard's.

 

The duration is the time the valve spends open right? Lets have an imaginary cam. Both are 280° advertised duration on the intake lobe.

However when measured at .050" lift the LPE219 cam spends only 219° above .050" lift. While my imaginary cam spends 231° above .050" lift.

The valve spends more duration open on the 231° cam, which means that if the advertised duration is the same between the two, then the 231° cam MUST open that valve significantly quicker to achieve a higher duration at .050" lift.

 

Im lost with alot of these numbers lol...i did research on the 383 builds saw alot back in the day used the lpe219 i wasnt looking for a crazy cam but something that was going to make power and we run the First Performance intake so i wanted something to kinda match that too...plus we used a set of 113 heads fully ported and polished flow 250cfm i saw lingenfelter used the same head on his lpe 383 builds...

 

The LPE219 is a stand-by cam because it was a good cam back in the 90's. Its a single pattern cam so it tends to do better with heads that have a better intake to exhaust flow ratio. The better flowing the exhaust is, the faster the exhaust gets out of the cylinder, so you an close the exhaust valve more quickly and retain higher cylinder pressures. On a 383 with good flowing heads it retains great streetabilty and excellent mid-range torque without being too aggressive on the valve train.

Something like the AFR or other quality CNC'd aftermarket head have good exhaust flow. Its part of the reason why LS series engines seem to do so well.

 

Exactly. So the 219 is slower. That's where I'm going. Bring the advertised numbers and the .050" numbers closer together and that makes for a faster lobe.
To take it further, if the 280 adv and the .050" number were the same, that would be a square (or a super stock lobe!). Super fast. And hard on parts.

 

plot the curve shape of the lobe and you’ll see. Harvey Crane calls it intensity. Major minor and hydraulic. Plot the lift curves and use excel to get an equation for the curve. Derivative of that is velocity. Derivative of that is acceleration.

think of it like this, degrees of rotation is time, it took 71 degrees of rotation to move lifter up .046”. 71 degs of engine rotation. Look at a circle and see how long it takes to move 71 degs. Then think about moving a lifter up .046” in 56 degs of rotation. It takes much less rotation to move the same amount, so the lifter is moving faster

 

WE shall see how it performs looking for mid 12s its in a 89 camaro 3400 lbs 700r4 worked vigilante 9.5 in 2600 stall convertor..3.27s for now probably go 3.73s 36 lb injectors, holley HP efi system...holley dual sync dist... headers,into a 3 inch y pipe into a 4.5 inch mufflex exhaust it will be going supercharger at one point to its fully forged 4 bolt main motor... but would be very happy with mid 12s on Motor.

 

Same amount of lift but less degrees/inch. So to get from zero to 50 thou in 56 degrees or zero to 50 thou in 71 degrees...which gets there sooner? I see the greater number of degrees involved though.
I think it's a question of semantics.

 

My potential build is somewhat similar to yours in that I also have about a 250 CFM max port flow. Conversations here and elsewhere tell me I'll be RPM limited and can expect peak HP RPM at less than 6000. This isn't necessarily going to hurt torque output (as it's been described as a tow truck engine) but the reduced RPM will put a cap on HP.
You'll still fly though. Mid 12's easy provided you're not traction limited. I've been there with a lot less engine. I'm hoping to be in the 11's. But just.

 

I know it should be a fun car to drive tho... and once its supercharged it should really move...i think....lol

 

in terms of rotational time 56 degs is sooner. Distance in time is speed. Same distance in shorter time is faster speed.

Heres another example. You think oem gm cams are aggressive? They have to last 100,000 miles on springs that are 100 lbs or less on the seat.

stock 01-02 ls1 cam. 70 lbs seat pressure 220 open. Revs to 6000 easy
advertised .006”. 281/287 deg
.050 dur. 196/201 deg
.467/.479” lift with 1.7 rockers

thats a very mild lobe

 

Exactly my point. Of course there's more to it from an overall lobe perspective but I was directing my observation towards two profiles and the difference in lift-degrees. I'm calling one that has small gap in duration in the 1st 50 thou as being "faster" but I can see the choice of words may be interpreted in different ways. Now if you want to call one with a wide spread in lift-degrees as a "mild lobe" I can live with that.

 

You were saying 280 to 219 was quick.

Well its a quick drop in degrees, not exactly what you want for power.

I took that to mean you thought it was a faster more aggressive lobe. Faster as in opening rate. Im saying its not, its slow ramp opening rate.

 

I've thought about this far too much. And I see your point and agree.

 

Just as a FYI, at one time Erson (part of the Accell group) ground the "LPE219" cam and the specs were 280/219/0.525-112. Later Comp started grinding the cam and from what I’ve been able to tell the only difference at that time was that the ones ground by Erson had 4-degrees advance built into the cam (108IC/116EC) and the Comp grinds didn’t (112IC/112EC).

However, it appears judging by the instructions for the CURRENT LPE219 on their website there has been at least one revision (don’t know when) since that initial transition. It is now listed as 270/219/0.527-112.

You can’t say for sure how similar two lobes are since you only know three lobe parameters, but the closest thing Comp has to the “new” LPE 270/219/0.527 lobe based on those three parameters is the 3034 Xtreme XFI “exhaust lobe” at 270/218/0.521. Judging by the current LPE219's recommended Comp 977 spring’s seat pressure of 135lb (@1.9") and a spring rate of 441lbs/in, my bet would be it is based on or closely to the XFI lobes – which as a whole are pretty aggressive.

 

Couple of quick questions for you GD.
What would the factory head gasket thickness have been?
You mention decking the block and the result was .025" down. What amount was removed? What was your final compression ratio?
The reason for asking is that there's another chap here at 3rd gen with a new L31 (yet to be purchased but it'll be new from Scoggin-Dickey or similar) and he's looking towards a Vizard spec'd cam (he's bent on going with an 108 LSA as is Vizard's approach) to go along with the factory 9.3:1 CR. Kind of puts him in the 262-270 advertised duration range and probably going with a Lunati/Vizard offering. DCR with the 262 is 7.95:1. With the 270 it's 7.75. Not sure if there'd be a decent bump in CR with a change to a shim gasket as you've done.
​​​​​Do you have a part number for the PAC springs and related hardware?
Thanks in advance.
EDIT: Reread your posts and I see your CR is 9.8:1.

 

Well - I don't know what amount was removed because the block was also line honed and the rods were resized for ARP hardware..... so my machinist may not have actually changed how far in the hole they were at all. Or maybe he did...... but after the machine work they are all the same. That was mostly the goal.

The gasket I used is the 0.015" shim from FelPro. Stock compression would be about 9.5, and I calculated mine to be about 9.8. The exact compression wasn't much of a concern to me - I was after the quench being 0.040"

The PAC 1218 springs are what I used. 1218 is the part number. You need the COMP 787 retainers.

And NO HONING! Didn't touch the bore's with 177k on them. They looked great and performance is excellent.

GD

 

Well..... Looks like I've likely cracked one of the Vortec heads. They did have 177k on them and were not the ones with exhaust valve seat inserts. I have excessive crankcase pressure and now cooling system pressure that's pushing coolant into the overflow. No coolant/oil mixing thankfully. Oil looks clean. And no steam out the tail pipe or roughness on start. Doing more searching it does seem that Vortec heads cracking is rather common and I sort of massively abuse this high mileage set with ~400 HP. Can't say I'm surprised and hey! It's excuse for the AFR upgrade to test out the power increase on the dyno!

So today I ordered a set of AFR 195's. 65cc, straight plug, with 7000 rpm springs. Fortunately I had the forethought to have Ken drill my FIRST manifold for both stock and Vortec intake patterns.

3-4 weeks out. So I have some time for tear down and failure analysis. I'll post back with pics, etc.

GD

 

Hmm. Seems to me you have "willed" this to happen. I like your glass half full look at it too.
The 195's from Vortecs is a step function change and one thing will lead to another. IIRC correctly it's a stock bottom end?

 

Will be interesting to see how closely the gains match the Desktop Dyno graphs I posted. Which showed about a 44hp gain, and power peak moved from 5500 to 6000.

 

Was that heads only?

 

Between the two, yes. I based everything else off what was listed at the beginning of this thread.

 

The Vortecs could make 440 HP and more with the right cam. I see the AFR's are 270 CFM so that could be 540 HP. But again with the right cam. So I can see a solid 40+ HP gain with heads alone as predicted. Target the new head airflow for a new cam spec and that makes up the difference.
Question is GD. Are you gonna go big or stay home? Those AFRs have a lot of potential.

 

Well - if I were to change the cam - what would be the crowd's recommendation? I wouldn't want anything that idles worse than the unit that's in there now. I have about 12-13 in/Hg, and I keep the idle around 900.

These heads, as built, will do 0.650 lift and 7k rpm.

And yes the bottom end is stock 97 Vortec. I do have it blueprinted with very strict tolerances and I have amazing (shocking actually) oil pressure that is typically 45+ at operating temp with 30 weight. I have spun it to 6500 without any complaints.

GD

 

Mistakes were made. I've been working on the cooling system and also getting the AC working with the new Sanden 8 piston compressor and the engine did, at one point at least, hit 250 F on the coolant temp. Not a huge amount over "normal", but not ideal either.

Additionally there was a period where the ignition advance wasn't working due to a mistake made in translating my tune to a newly released LINK product I was evaluating - didn't catch that right away so some time was spent at WOT with the timing locked to about 8 degrees or so. That certainly drove EGT's through the roof and almost certainly was a contributing factor....... the price you pay for proto-typing new hardware sometimes. Better it happens on my test car than in a customer's.

The heads had 177k on them. Were rebuilt and pressure tested but that just removes material and these heads didn't have the hardened valve seats. From what I read the consensus is that somewhere between 1 in 3 and 1 in 2 Vortec heads are already cracked upon tear down and are not suitable for rebuilding - and that's in stock 250 HP form. Doubt I did them any favors on a high power build in a chassis notorious for cooling problems.

GD

 

Exactly why im hesitant to recommend vortec builds lol.

i would run it as is with the head swap if you arent looking for worse idle. To really step up i think more duration and lift would help there but that will hurt your low speed characteristics. 280 xfi comes to mind

or i would go to a custom Xfi intake lobe 224-226 duration and either xfi exhaust or xe exhaust 230-232 or so. That will get you more lift on intake side. 112-113 lsa would idle better. Even tho i would like 110-111 lol

small difference in cam to go with the heads, probably only few hp to be found within same power band, but either will work ok. The nitrous hp is not terrible and you should spray it later anyway

 

Keep the cam. Same tune. Same compression ratio. Then dyno it and compare it to the Vortec (naturally).
It would be interesting to see if the AFR's lose anything in the lower RPM ranges. You'll most certainly make more upper RPM HP.
As for another cam recommendation, considering what your objectives are, there's probably not a lot to be gained with a "sideways" move away from what you have. Now if you want to stretch the AFR's legs, then it's a different matter.