I'm sure this has been beat to death but I searched and couldn't find exactly what I was looking for.

Ok I have been looking into possibly getting a weiand 144 blower. I can get it through work (advance auto) for less than 1100$ tax and all.

I would like to make 400-450hp tops with some decent heads (maybe world products sportsman II's or ported stockers (not my swirlports i have thought)

I may just stay with my current camshaft (lt4) and throw in some roller rockers.

Will be running 1 3/4'' slp shorties to a 3'' hooker catback.

My question is......

Will this blower fit under my 3'' cervini cowl hood?

How much boost do these blower make?

The version I am getting is made for V-belt cars....(serpentine ones are 300$ more). What would I need to change to make this blower work with: serpentine or what would need to be swapped for me to go to v-belts.

Car will be street driven a lot. Probably 8000-9000 miles a year. I have heard roots blower wear out fast. Is this true? I also want to stay with one carb...maybe a 750 double pumper.

Would that setup make over 400hp and be street friendly? I have 9.6:1 compression now but If I decide to do this I will be getting 72cc-76cc heads to raise the compression.

Last but not least should I do this or just go with my original plan of installing a 100hp edelbrock nitrous system?

 

Let me see if I can help here....

Getting the regular long-nose Weiand 142 to fit with a serpentine belt ain't gonna happen. The blower belt and the serpentine belt will want to be "occupying the same space" near the water pump by about 1/4". Weiand makes a super-long-nose version of the blower that will clear the serp belt but has limited pulley diameters available for it. namely, the bottom pulley is only available in 6" diameter (the smallest) and you will be limited to about 400-425HP even with the smallest top pulley. Maybe you can live with that. I was pushing about 5 PSI against a mild 383 using a 6" bottm and the smallest top pulley available. That would equal about 6-7 PSI on a mild 350 and make about the same HP, all expe being equal.

Fitting under a 3" cowl hood... Marginal at best. I have one on my 78 Malibu with a 2.5" hood and it's REAL tight. I played around with my air cleaner combo for days to optimize it, but it's still real tight. Your 3rd gen has less hood clearance than my Malibu to begin with by about 1". I would think that a 4" hood would be MINIMUM on a 3rd gen.

Possible solution- the Holley 144 version of the blower sits about 1/2" lower overall than the Weiand 142. That would buy you a little room. Just mke sure they have a version that would clear your chosen accessory belt configuration. Lots of variables to juggle when you think about this. I'd DEFINTELY call Holleys tech support and tell them what you are trying to do before you choose. An extra $300 might be money well spent and save a lot of headaches.

Roots blowers last a good long time if you watch the blower oil level. Mine has been on my Malibu for 2 years of weekend driving and no problems. It's consumed maybe 1 oz. of gear lube in that time. The main thing with these "mini-blowers" is to NEVER EVER OVER-TIGHTEN the blower hold-down bolts. Directions say 12 ft/lbs MAXIMUM and you damned well better believe it. You'll feel awful goofy using a torque wrench set at 12 ft/lbs on a giant 3/4" bolt, but you better do it. This is the #1 killer of these blowers. Short engine life beyond that is almost always due to improper tuning (too much advance, running lean) or bad parts selection (too much compression, bad cam choice, weak bottom end). Beleive me- follow their recommendations on total spoark advance. 28* maximum sounds real wimpy for a N/A engine, but it works just super on a blower motor. I run pump gas, 8.7:1 compression with aluminum heads and 28* maximum advance on my combo, and I leave the secondarys jetted rich just for safety's sake. Much safer than my old combo with 9.2:1, iron heads and 32* advance. The old combo had definite signs of detonation going on when I tore it down.

You want to keep your compression LOW for a roots blower. 9:1 with aluminum heads, 8.5:1 with iron heads for a pump gas street motor. It won't take super high flowing heads to make a REAL 400 flywheel HP. I was making about 425 with a set of box-stock Dart Iron Eagles.

Call Holley and ask some questions. Then feel free to email me and I might be able to give you some more real-world pointers from there.

 

I had around 25k miles on my B&M 144 (now Holley) when I rebuilt it....it didn't need the rebuild but I was being safe, probably could have gone another 25k before it really needed it!

 

whats the spec's of the lt4 cam

you can make an ez very streetable 425hp with that blower

 

The 142 is the one I was looking at. My bad.

I would switch to V-belts if I could get more pulleys and parts for it cheaper. I only have alt, ps, and water pump anyways. I wouldn't care to switch it over.

What is the max boost?

I have 9.6:1 with 64cc heads but if I decide to do this I'll probably get some 76cc heads.

With a stock bottom end how much boost could I get away with?

 

I have a question....what kind of carb should I run? Besides the expensive supercharger carb from holley?

I heard somewhere that I would need a specially modified power valve. What is the story behind this?

 

is this because of case flex?

 

do a search, Damon has talked about this

also do a search here to

http://www.nastyz28.com/cgi-bin/foru...e=5&LastLogin=

a sc carb would make things a little ezer i'd think

 

I run a home-tweaked Qjet carb on mine. There's nothing special about it. It's got the same claibration as when I ran it on a N/A motor except I fattened up the secondary rods a smidge, just to be safe.

Boost-referenced power valves aren't really necessary for the street at modest boost levels. On my engine I'm still pulling about 4-5" of vacuum at the carb when the motor just begins to jump into boost. So I'm still into power enrichment (mine is calibrated to kick in around 6" vacuum) by the time the cylinders see positive boost. In other words, a stock 6.5" (or slightly higher) Holley power valve would probably work just fine for the street.

On a mild 350 you should be able to get as much as maybe 8 lbs boost with the highest pulley set available, but your cam and heads make a BIG difference in the actual boost produced. If your engine is near-stock you can make more boost than you probably really want. On a modified engine with good heads and a bit of a cam you'll see a lot less boost. I have a 383 with AFR heads and a 224* blower cam and I see 5 PSI with the next-to-highest pulley set available from Weiand/Holley.

Mr. Dude- Yes, the hold-down bolts on the 142 and 144 tighten from the TOP of the blower case all the way down into the lower intake (a big XX-71 type blower has lots of little bolts around the base of the blower case, and so, they don't exert distorting forces on the blower case itself). The blower case gets "squeezed" by the bolt torque. Too much and you bend the case just enough to allow lobe-to-case contact when everything gets heated up, instantly destroying the blower. Holley will repair it in their reman department, but it'll set you back about $600. Expensive mistake to make. Ask me how I know.

 

When you have these blower rebuilt what is the approx. cost of the rebuild?

I am trying to decide if I want a roots blower or nitrous. The way gas prices are looking these days nitrous doesn't look so bad anymore. I think it would be badass to have a roots sitting ontop of my 350 though.

I'm worried about hood clearance though. I have a 3'' cowl already.

 

Huh, are those hold down bolts necked down or something? Typically, 12lb-ft is nowhere near enough to keep a bolt that size torqued down/properly stretched. You'd have to neck it down to about ¼", maybe 5/16" to get it to clamp correctly.

 

They're not necked-down. They're like hardware store bolts you would buy to bolt the deck together on your house. Getting stretch on them is not anywhere in the plan. They are there just to hold to blower LIGHTLY in place, without warping the case. They come with special brass washers that help them "bind" in place so they don't back out. I've run my blower for 2 years at only 10-12 ft/lbs and never had one back out. Plus the blower case itself provides the "spring" action to hold constant pressure on them.

Like I said- you'll feel alwful silly setting these big, huge bolts down to only 10-12 ft/lbs with a torque wrench but it IS the only right way to do it.

PS- I also make sure they spin REAL EASY in their threads before applying torque to them. At only 10-12 ft/lbs even a "tight" thread can throw off the torque enough to cause problems. After destroying one blower from over-torqueing these bolts you get real **** about stuff like that.

 

Rule of thumb: if you can't turn it by hand, the threads aren't clean enough.

FWIW, when stuck with low torque values like that I usually resort to an inch pound torque wrench, which instead of being at the very end of it's scale will be in it's happy place...