Kingtal0n

The Blower is on the way, and now Im ordering a camshaft to go along with it. I dont want a Crane Cam, thats for sure. Im pretty sure im going with Lunati, But they make 2 Models Im deciding between. I will be ordering this weekend....
Duration:
Intake: 234 (I) @ .050
Exhaust: 244 (E) @ .050
Intake: 303 (I) Advertised
Exhaust: 313 (E) Advertised
Intake Lift: .488" (I)
Exhaust Lift: .509" (E)
LCA : 112°
---OR---
244 (I)
254 (E)
313 (I)
328 (E)
.515" (I)
.536" (E)
112°

Im not worried About the Idle Quality, Ive got a 3500 Stall converter so Idleing is not a problem, What im mainly concerned with is the top end performance, I realize more radical cam will make more top end, but it may push to far out of my power band...
#2 can ride up to 6800 RPMS, #1 6500 RPMS,
The shift in power curve (#2) will likelly make my torque peak later, closer to my stall point, which may give me alot more off the line power with the blower, BUT, The Horsepower Peaks above 6200 RPMS and i wont be revving past 6000.... Naturally, Im not concerned with gas mileage but I dont always beleive bigger is better. The #1 cam may yeild better street manners, and wont care about my single pipe-exhaust as much... I have no clue what to choose, Im leaning towards the Smaller cam though, just because...
What are your thoughts?? #1 or #2 I should have done a Poll heh....
It will be a B&M 144 Powercharger, 6-7 PSI of boost, 355 Engine, 2.02 / 1.60 valves, .575 max Lift, Performer RPM heads, 8-9:1 Compresion ratio, 750 Holley blower carb, Th350 3500 Stall, Headers with Hooker Y-pipe and 3" back to single muffler and out.
Desktop Dyno estimates 450 Torque at 3400 RPMS and 580 Horsepower @ 6500 RPMS. I wont be going past 6000 Though, which puts me at 540 Horsepower and the torque is still peaked from 3400-6000 RPMS, around 450... which is why im leaning to the smaller cam, big flat torque curve right in my stall range....

IROCKZ4me

Those don't sound like numbers that most blower grind cams have (at least not for a 355 redlining at 6000 RPM) so I'm assuming they are designed for naturally aspirated engines.
You don't need as much duration on the intake side with a supercharger to make excellent top end. You can improve bottem and midrange, that way, and by widening the LSA to make more cylinder pressure earlier, getting your power curve down under your 6000 RPM redline where you can actually use it.
A lot of people like Comp Cams blower grinds. I would reccomend giving them a call to see what they would suggest for you.

Compaire the cam specs (particularly duration) for the two blown 434 CI small blocks with really big heads in this post.

Kingtal0n

Thats just it, Why go for midrange or low end when i dont even SEE midrange or low end with my stall? This car has to be all top end, otherwise its a waste. thats why im considering a much smaller stall, but then the car becomes too streetable and blah blah blah i get concerned with gas mileage then i wana go lockup which puts me 700R4 and more more more money. Just cheaper to throw a big cam in it that can use the top end of the stall i figured. Those cams ARE lunati blower grinds. the 112 i assume instead of the 114 will help 2 things from my point of view:
1: Bleed some compression off because im over 9:1
2: Exhaust valve will open later than a 114 for more power.
Im just concerned, I had a similar cam in it before, it ran very nice, but without the blower... It looks like the blower shifts my power curve over the 6000 mark, without it, the cam puts peak horsepower right at my shift point. I guess ill just revv it to 6500... It should handle that, with no more than 7 PSI of boost. I guess. If not, I blow it, and i repace it with somthing to go 7K and only rev it to 6500 and it will last forever

B4Ctom1

please check out this thread it is very pertinent https://www.thirdgen.org/techbb2/sho...threadid=83372

dmair5_0

I hope that this car isn't a daily driver or anything. Cuse ther is one thing I know and that is a street car that is all top end is no good!! I wasted a friend repeately around the street with a motor he comfortably winds to 6500 with MY STOCK LO3. Quarter mile is a different story, I know that, but point is, for driving around the street you want TORQUE! But it sounds like you'll have a nastly little racer there.

IROCKZ4me

Something else to think about, just in case you didn't know:
That 3500 stall converter will flash alot higher than before once you bolt that roots style blower on there with all the increased torque it will generate.
You may already know that and it may not even be an issue for you, just making sure you know.

Kingtal0n

IROC thats the main reason i invested in a blower. Before with the "mild" cam profile and engine profile it would only flash to about 2600 RPMS... Pissed me off in reality. I decided the quickest route to power was a blower in my case, without a rebuild. Little did i know i spun a rod bearing... i found out AFTER i decided to rebuild it anyways. It would have blown sky high if i just bolted the blower on...
Anyways, yes i am HOPING for a much higher stall when i mash it, and the mind numbing power that follows.
I ordered all new stuff for it, Lunati rods, forged crank, lightweight forged pistons, lunati cam, Timing GEAR set, and of course the blower. here are some interesting pics...

Kingtal0n

here is a pic of the blower i set on top of my block while its in peices...

If you look CLOSELLY you can see the piston rings i bought. I File Fitted them for each bore, and they are resting in the bores awaiting my new pistons. Moly Plasma File fits by SpeedPro---

Kingtal0n

here is the stuff i pulled OFF the motor prior to being pulled out.

Kingtal0n

And Say, i suddenly want a daily driver out of this thing. Sure 8 MPG isnt a bad thing, but i could get more. MUCH more. How?

Cam Swap + torque Converter Swap = Daily Driver

Nice mild cam to replace this 7000 RPM screamer, somthing that will take advantage of the low RPM tire shredding torque these blowers are good for, and a nice tight stall to match, like 2000 RPM stall. Insta-Daily Driver with 500 horsepower

And gas mileage to boot

anesthes

iTrader: (12)

I think that cam might be a little too big. Unfortunately, I'm not at my shop right now so I can't run your numbers. I'm a little concerned about the duration, and how much boost you may loose out your exhaust.

-- Joe

Kingtal0n

I had a choice, 114 with lower duration, or higher duration with a 112. the 114 sounded good until i realized the cylinder pressure would be insane at 10 PSI of boost down the road, i backed off to the 112 so scavenge some exhast and bleed some compression off. i added duration because I like revvs and a lopey exhaust note. Im also running 9.5:1 compression, which makes the 112 all more feasable. Its coming together as we speak...

Damon

I have the very similar Weiand 142 on my 78 Malibu right now.

Here's what I can tell you about it from expereince (this is my 3rd install of this type of blower): It won't feed a fire-breather. It just won't do it. The factory (Holley) recommends no more than 5500 RPM redline with these units. I spin mine to 6000 and it works fine. But don't try to crank out 6500-7000 with these- you won't like the results.

The little 142/144 spins the lobes at roughly a 100% overdrive right out of the box, to make up for it's small size/displacement. But spinning roots blowers to insane RPMs gets you quickly up into the part of their operating range where they become very inefficient (they heat the air up a lot and boost starts to fall off).

Go with the smaller of your two prospective cams. In fact, it's probably too big still. You think putting in a small cam is gonna jack your cylinder pressure way up but that's not going to be a problem here. You're running 9:1 compression which is perfectly acceptable for use with this blower. I run 9:1 on my motor now and it's nowhere near detonation at 6 PSI on pump gas with iron heads. You really don't need more than about 225-230* of intake duration. And I wouldn't go any skinnier on the lobe sep than 114* unless you take the duration under 220*. Overlap allows the boost to blow right out the exhaust which is the one thing you NEVER want to have happen on a boosted application.

Your comment about building power above your stall point is a valid one. However, in general I think you could do better with your cam choice.

BTW- How are you goign to build 10 PSI of boost with that blower? It only comes set up to make 6 PSI on a mild/stock 350. And there's only one smaller pulley available from Holley to bump you up to about 7-8 PSI. ??

Kingtal0n

Weel there are pulley available to get it to 10 PSI of boost... according to holley. I understand the whole duration thing, 232 IS a mild duration for this engine.
Figure this:
I HAD a 224 Duration cam in it, Idled Smooth as stock at 500 RPMS.
<b>Problem: NO POWER! Overstalled, (3500) Undergeared (3.08) bad engine combo (Hyperucraptics + stock rods) =
CRAP!</b>

Im sure you will agree that was a bad setup no? A cam that made power right off idle + a 3500 Stall ???
OK NOW:
I already have the stall, Im not changing it! its brand freaking new....
Since it stalls to 3500 RPMS, Doesnt it make sense to begin the peak torque curve at 3300 RPMS? with this cam (234/244) it will begin around 3300 RPMS -Under Boost- and carry all the way to 6500 RPMS... Ill probably shift at 6K just for Longevity / Overdriven blower reasons... like you suggest... I AGREE....
BUT... A cam with LESS duration will DROP my power curve BELOW my stall, and cause me a lack of power-off the line.
AND Figure THIS Into the equation:
I MAY remove the blower at some point in time, and this cam is PERFECT for the 3500 RPM stall even without a blower...
<b>SO....</b>
You see the cam may not be <b>IDEAL</b> but it will Suite my Application just fine,
<b>I agree</b> a smaller cam would be more street friendly <b> but so would a lower stall</b> and i cant afford it right now...
In no more than 6 months i will probably changing my cam out for the more desirable 224/234 and lowering the stall to Near stock speed, therefore giving myself an excellent daily driver / street rod.
<b> does this make sense now? </b>
I appreciate your help its making my life much easier, im very interested in what you have to say.

Damon

Well, if you're gonna intentioally overcam the motor I'd overcam it a LITTLE, not by a lot. I know what you're shooting at here and I agree in principle with your thought process. It's just that I think maybe you're going a little too far. Stick with the ~235 duration cam.

It will still idle very smooth, but don't be fooled- it will make power where it's supposed to. The lobes of the roots blower do a fantastic job of preventing intake reversion back through the carb. Result- smooth idle even with a lumpy cam, versus a n/a application.

I would HIGHLY recommend you measure your boost with a boost gague and not take Holley's word for it. They rate the boost based on a near-stock 350, not a heavy breather like yours. Even my mild 383 outruns the blower pretty bad- I get barely 4 PSI max boost with the stock "6 PSI" pulleys.

With my Weiand 142 blower there is only one step up from the stock pulley. It's a smaller driven (top) pulley. 2.85" versus the stock 3.15" pulley. Maybe the Holley version of the blower has a broader selection.

BTW- make sure you have a BIG carb on top of this setup. If you're trying to feed it with a tiny little 650 double pumper forget it. You want a big honkin' 850 to feed this beast. The carb isn't under pressure so it must flow a LOT to keep from being a restriction. Totally different than a blow-though type application. No better way to kill top end power than by under-carbing a blower app like this.

83 Crossfire TA

iTrader: (2)

Wow, you’re working on a mismatched setup. You’ve got a blower that likes low and midrange and picking a cam that’s all top end. The converter, well, it really depends on the brand but the converter is probably too high a stall for the blower and too low for the cams that you’re listing (hopefully it’s something like a PI or Yank that is a pretty good compromise between high stall and drivability).

With a positive displacement blower you really want to go with something a little on the small side then give it a couple of extra degrees LSA. That way you don’t blow most of your boost out the exhaust and the little bit of loss that you get from the small cam at the top end is made up for with boost.

Best case scenario is if the whole engine is built around the blower you’ll have much larger exhaust ports then normal, then you’ll probably want to look at something like a 215-220 @ .050 intake and exhaust with a 114 LSA. With normal heads you’ll want to go a little smaller on the intake and larger on the exhaust, still with a 114 LSA.

To give you an idea, my brother just went 118.7mph (spinning the whole way) in a 3300# car with a 302 ford (think small chevy with crappy heads) and a small Eaton M-90 blower, seeing only 4-5psi boost (that’s a mid to low 11 with traction). His cam might be a little big, but it’s a 218 226 @.050”…

- mmp

Kingtal0n

Sigh* its not put together yet. The cam is 234/244 @ .050 LCA 112

Now youve all got me thinking.... alot...

Ok let me check if i can *sigh* return the cam in exchange for a new one, and see if that guy still wants to buy my stall converter...

The carb is a who-knows-what it came with the blower, front powervalve is blocked off, back one isnt, adjust-a-jet installed on it, No main jets (of course) 50CC Accelorator pump.. i cant tell if its a blower carb or not tho...

Would you all recommend... say... 224/234 @ .050 LCA 114 on the cam? thats what i just pulled out....
and as for the stall... if i sell this converter, what converter should i buy and what stall... im thinking it will idle smoothly around 600 RPMS in gear so i could even use stock stall, but maybe a little less tight? blah... now im done for...

B4Ctom1

eek, edelbrock heads, you may wish to consider "E-bay"ing them off for something more substantial (they are barely larger than stock port size) unless they are victors (then sell them just to me he-he) atleast you got aluminum. those trick flow heads ($895) look pretty good compared to the performer and RPM heads. your ride is goanna have so much torque, man!

Kingtal0n

<b>
Damon:
Your comment about building power above your stall point is a valid one. However, in general I think you could do better with your cam choice.

83 Crossfire TA :
Wow, you’re working on a mismatched setup.
</b>
Im getting this sick feeling in my stomach. this post has done me wonders so far, kept me out of the pit, but now, i think im falling headlong into it.
Building a street / Strip car, isnt as easy as it may sound apparenty!

According to desktop dyno (if you trust it) The smaller of the 3 (three, my old cam being unmentioned) will yield more power and torque below 6000 RPMS:
224 / 234 @ .050 LCA @ 114
Apparently Desktop Dyno sees this cam as a savior, restores all my torque below 3000 RPMS and adds more.
this cam:
234 / 244 @ .050 LCA @ 112
Proceeds to <B> BLOW </b> the First cam away after 6500 RPMS, Where i WONT likelly be spinning since this blower is <b>NOT</b> very fond of spinning high RPMS i hear.

I think im going to return that $200.00 Lunati camshaft and simply re-install my OLD camshaft, NOT A BLOWER GRIND its actually a BLAZER cam, by crane. In THAT Light of evidence, Do you agree with me? and also, does everyone agree I should LOWER my stall speed seeing that i Love to drive this thing on the street?
And above all, does this make sense? Does desktop Dyno really prove a point, make it worth it?
Suggestions very helpfull at this point, Im about to put it together!

83 Crossfire TA

iTrader: (2)

We’re just trying to help you to the best of our knowledge to get a combination that you’ll be happy with.

My experience with desktop dyno is that it is fairly accurate with NA applications, and almost as accurate with positive displacement blowers (we modeled my brother’s engine on it and got very similar results to what it predicted), a little less so with centrifugal, and way off with turbo motors (the turbo sizing appears to work backwards, if you put a turbo that should flow more air you get less power no matter what you do, to the point that to get substantially more power then na you have to put an insanely small turbo on it). The point of inaccuracy with all combinations is how accurate is the information that you give it, all combinations tend to give slightly ambitious power #’s, and with superchargers it almost seems like it doesn’t account for losses to drive the blower (in other words, it’s worthwhile for examining trends, but don’t expect to pull the # on the dyno, especially on a blown car).

What happens when you take the cam timing down to about 218/230 with a 114 or 116 LSA? Make sure that you keep the cam ground 4 degrees advanced, try this (double check this because I’m working it out in my head while I’m typing and don’t have a copy of DD on my laptop to check it, these are .050” #’s):
Open Close
Int -1 39
Exh 53 -3

This _should_ be 218/230/114 ground 4 degrees advanced. (this should be very close to a popular Comp Cams blower cam)

Then try advancing and retarding the cam 2 degrees from there, if one gives you more of the power band that you’re looking for try 4 degrees. Tell me what you get.

I’d say that the smaller cam that you’re describing is much closer to what you want to run, considering that you want to drive it on the street, I’d bet that in the car you’d be happier with something a little smaller (say 215/225 with a 114LSA) even though I suspect that DD will show it substantially down on power at the top end.

I’ve told people this before, that running the bigger cam will make the motor feel like it’s running a bigger cam, more brutish, which is fun for about 10 minutes, but gets old fast when you run slower at the track and you can’t tool around as well, have problems tuning it for anything but WFO…

What converter is it? What are the specs on the blazer cam?

Building a street strip car isn’t hard, building one that works well is. I believe that 90* of them are mediocre combinations, but the owner rarely knows that it could be better or what to do to get there.

Kingtal0n

Int -1 39
Exh 53 -3

Your cam profile sort of shifts everything to the left a LITTLE... the horsepower drops a LITTLE and the torque comes in a LITTLE sooner, but not much at all. its about the same. at 4* Advance it looks OK but it looks alot better and smoother at 2* advanced.

The blazer cam is:
Int 3 41
Exh 56 -2

they are almost identical. and i already have the blazer, sitting here, its brand new, i broke it it, then pulled the engine apart. i could throw new lifters on it and be done with it.

My stall converter is a TCI 3200-3800 Stall 10" Converter. I dont like it... seems to eat gas eay too much for me!

I would love to sell it, and buy a better one with less stall. what stall do you recommend for me? At 2000 RPM it shows 400 Ft. Lbs of torque, so I imagine near-stock stall wont be a problem. I HAD the cam in my car before, it idled smoothly at 600 RPMS without lope, pulled 15" of vaccum at idle. i hated it... but it may work out for the best i suppose. whats a good converter for my application? and what will the blower do to my idle?

Damon

The idle quality question I can address. I touched on it before but I'll lay it bare here........

A roots blower will cover up a multitude of tuning sins. They are fantastic at taming down a wild cam and even marginal tuning. 2 reasons:

1. They act as a one-way valve into the engine completely preventing the intake reversion so common with a lumpy cam.

2. They thoroughly blend the A/F mix before it goes into the engine. Like having a food processor between the carb and the engnine. Good atomization and near perfect cylinder-to-cylinder distribution are the result.

A 2400-2500 stall would work well with this application, IMHO.

Just a final though on the cam...... As I said before, I think the 234* cam is too big (83Crossfire and Desktop Dyno agree with me) BUT..... you may try plugging it back into desktop dyno and open up the Lobe Sep. Angle to 114* or even push it out to 116*. I think part of the reason your smaller 224* cam is making more torque below 6000 is only partially related to the duration. I think the overlap is at play here, too. The total overlap on a 224*duration/114* LSA cam is MUCH less than that on a 234*/112* LSA cam. All that overlap with the larger cam is opportunity for the boost to blow straight out the exhaust, lowering your torque production at moderate RPMs. Play with the Lobe Sep angle and see what you get. Some cam manufacturers (Comp, for one) will give you a cam with whatever lobe sep you want for only a little more $$$ over an off-the-shelf grind.

Kingtal0n

<b>A 2400-2500 stall would work well with this application, IMHO. </b>

Thats the ticket. I've finally decided on my route:
2400-2600 B&M Holeshot converter.
234/244 @ .050 112 LCA camshaft.

My reasoning is sound, i think, although desktop dyno likes the lower duration and wider separation angle, the changes in power are small, and this engine will likelly be revved up alot. the camshaft has a red-line of 6000 RPMS which is perfect, while the SMALLER camshaft has a redline of 5200 RPMS, which I dont like. this assy will easilly spin to 7K however. spinning it to 6 only will make it last a LOT longer. the blower too...
I've had this camshaft installed in the engine a while back as well, without a blower, and it was great. the smaller cam, however, created a dog out of my car. The cam is the best of both worlds, if i ever remove the blower it will still run great, and with the blower it still moves along. not to mention, it does make an extra 50 horsepower @ 5500 RPMS on desktop Dyno, which is important to me. Im lowering the stall so i can drive it on the street more frequently and save some gas.
Ill update you all when I start getting it together, the machine shop has my rotating assy right now.

83 Crossfire TA

iTrader: (2)

I didn’t mean to imply that the cam that I gave you was perfect for you, it was more of a baseline, since you were mentioning 3 different cams and I had no idea what the timing was on the blazer, I suspect that it didn’t make as much power as the blazer did in DD.

One thing that you’re not clear on. The #’s that I gave you should have automatically put the cam 4* advanced, when you are saying that it looks OK 4* advanced do you mean 4 more (in other words 8*), or as ground (I guess that would answer the same question for 2*)?

The rest of what you’re saying is the about right about that cam, it should just barely lope more then stock, though I’m surprised it idled at 600, probably more like 800. That’s sort of the problem, often with power adders, the best solution is not the one that sounds the coolest, turbos are worse then this in that way.

Aw hell, how does this sound (best bang for the buck):

When it comes down to it, in the real world I really doubt that a few degrees going either way will make that big a difference, the blower and it’s size is what is defining your power band, it’s location and shape.

What would I do if I were you? I’d probably stick with the blazer cam (money already spent, and not bad), unless it’s going in a heavy car I’d probably retard it 2-4* to make it feel like a bigger cam while keeping the fairly low overlap that the 114LSA and fairly short lobe timing gives you (in other words, compromise between the low end that that blower wants and the race car feeling that you want and the save money that your wallet wants) . I’d try to sell the converter (would be difficult, not only are used converters a pain in the butt to sell because there is no way to really tell if they’re good without putting them in a car, but that one is not very good for street use), and any money made by not buying another cam/selling the converter would go toward a PI, Yank or similar converter (talk to them and go with what they recommend, they’re usually pretty good and I suspect that they’ll recommend something in the 2600-3200 range, but even at the high end of that it will feel very different from what you’ve got).

If with all this the drivability or times (fattening up the midrange with a smaller cam could make it faster) are not what you hoped for or it feels flat in the low to midrange then I’d look at smaller acting cams (ones with more LSA, maybe even the Magnussun or B&M positive displacement blower cams), or spinning the blower faster (I don’t know what that blower’s limits are though)

I’d bet that you’ll end up with a combination that will scare you on the street anyway.

Kingtal0n

I thought about sticking to the blazer but i already have the Lunati cam, and i cant return it so im stuck with it anyways. Ive had good luck with it in the past so im going to use it. not to mention I dont beleive that blazer cam is very good, i hated it when it was in my car. its got less than 300 miles on it. thats how bad i hated it, i removed it right after it went in. NO, no, i think ill stick to lunati...
As for the converter ill try to sell it on Ebay, and I cant afford a yank or vigilanty so Ive gota go B&M, for now at least.

83 Crossfire TA

iTrader: (2)

Well, if that's the case then I'd stick with the TCI, the B&M is similar at higher stalls and no better then stock at lower stalls, now worth wasting the money on (also very commonly will trash a tranny). TCI is fine in a race app, but sucks for street...

Kingtal0n

So If i want a 2500 RPM Stall converter for my TH350 where should i look?

83 Crossfire TA

iTrader: (2)

I told you what I would do. I've had good experiences with PI and yank, and have heard good things about coan and a few others.

Hell, I'm getting 2200-2300 stall from my stock converter behind a stock L98 (as per the data logs that I've done). Not sure why anyone would buy any of the lower stall B&M's, they feel about the same, run about the same and I've seen at least 3 trannies where there was evidence that they caused the failure. My brother threw his in the trash after seeing what it did to the input shaft on his tranny.

If you don't have the money stick with a stock one or the TCI you have, save it till you do have the money. Or waste it now and do it again with an added tranny rebuild later.

Kingtal0n

<b>I've had good experiences with PI and yank, and have heard good things about coan and a few others. </b>

Thats what i was asking, Where should i look? Ive never heard of ANY of those and cant find where to buy them from.

83 Crossfire TA

iTrader: (2)

PI (precision industries) makes the vigilante for GM trannies and stallion for Ford.

Yank, well is Yank.

I believe that both have web sites, I don’t know what they are off hand, do a search. Yanks is something like www.converter.cc

Kingtal0n

Thanks, Time for research.