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Stroker motor w/good heads vs. mild blower motor

4K views 14 replies 8 participants last post by  pdq67 
#1 ·
I have been thinking about this for a long time, and was curious what everybodys thoughts was on this. From info I have gathered over the years thru magazines and books, you could build a mild blown 350 with similar output to a built n/a 383 for about the same amount of $$$. From the dyno charts I have seen, a smog headed 350 with a small blower will make tons of low end and midrange power (up to a little over 5K rpms), while a n/a 383 can make the same kind of hp/tq numbers with a little more rpms (around 6K), meaning the 350 would need less convertor and gear, theoretically. So what would be the pros/cons of going either way?

Personally, I have never driven a car with a blower, although I did get to drive a grand national back in the late 80's and was VERY impressed. There is a guy around here that sticks blowers on everything. He had a heavy '78 camaro with 2.73's and a nearly stock 350 with a blower and 2 holleys on top, and it would run 13.20's easily with no traction. He also had a ratty '72 chevelle with a stock smogger 350 with the same induction and a mild cam and 2.73's that would burn a set of 275/60's off the rims at 40 mph. I have been playing with the idea of building a similar 350 for my old '78 truck that way I could keep my highway friendly 3.08's and still move 4500 pounds with some authority.

Any thoughts?
 
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#2 ·
Typical gearhead -- gotta go faster! Love the attitude! If you got room for a blower, Roots type, and carbs on top, go for it. Then you'll have the notorious belt whine.

My neighbor had an 87 GNX, 3.8L intercooled turbo,I was impressed, not only into the seat back, but, sitting idling, you would have swore it was a BBC listening to the pipes.

Some engine considerations are bigger ring gaps, looser piston fit, bigger radiator due to more heat generated, etc. I'm not a professional blower engine builder, I'd thinking out loud.
 
#3 ·
I was talking about this very thing to a friend last night. he was all geeked about wanting a blower motor, but cannot afford to build a new motor if he gets a blower and vice-versa.

I personally would go for a new 383 over a mild near-stock motor with a blower - seems the NA 383 would have a better chance at surviving a while.
 
#4 ·
And then down the road - add a blower to the 383!

Wretched excess!!
 
#5 ·
Travis, a guy here in town bought a new GM crate 350 and swapped in a blower cam, added a B&M 144 and a good Holley 750 with headers.It's in a '86 SWB truck and it's ran awesome for 10+ years this way.
I have talked to him on several occations and he said he would do this over again in a heartbeat. It has alot of streeability, torque and almost maintenance free since the build.

I have considered the same build for my new truck, but like the fuel injection too much...
 
#6 ·
If you take it easy with the boost and do the proper maintenance there is no reason a blower engine would not last just as long as a N/A engine.

I know a guy with a small single carb blower engine (400 block with a 327 crank) 2nd gen Camaro full interior, turbo 400, drag radials and runs in the 10's on pump gas. Also saw a guy at the track in a full size late 70's Blazer with a 350 small single carb blower, 20" or so rims low profile tires (not the best for traction) he was running low 12's/high 11's pass after pass.

Your question is tough to answer, because you are comparing two different beasts. I think they would run pretty close to the same, depending on how they were built and what size blower. For ease of tuning the N/A 383 would be the way to go. If you put a good set of heads on the 350 with the blower then that would change everything.

Run a timing retard and take it easy on the boost, I think a blower would be a lot of fun. What hot rodder never thought about or wanted a blower? Just something about them.
 
#7 ·
Originally posted by RickD:
And then down the road - add a blower to the 383!

Wretched excess!!
wisdom

this same topic comes up everywhere
tom izzo, owner of speed inc in schaumburg IL, was talking about why to do a big inch LS6 over a blower motor
the basic response was drivability and in the end longevity vs. maintenance
a mild blower would be lots of fun, but a good stroker can equal it

but I say add the blower later
 
#8 ·
The best approach is not to build a N/A performance engine and then add a blower. You have to build them differently. If you plan on building an engine with boost you need to have wider ring gaps, lower compression, forged parts are nice to have (not always a must), different cams specs (for best performance), etc... These same things that are great for a blower are not optimum for a N/A engine. The same rules hold true with all things being equal the larger engine will make more (torque and HP).

I am not sure why people think a blown engine will live any shorter of a life than a N/A engine. They are very easy on engine parts if set up correctly. There is added maintenance (oil in a roots type), bearings and the added expense of getting them freshened up every few years.

If you build a N/A engine that will make the same power (as a comparable blown engine) the reliability/longevity would not be any better (I would bet it would be far worse, due to RPM's, cam, and compression you would need to achieve the same level of performance).

The major drawback (only drawback IMO) to building a blown engine is the COST $$$, blowers are not cheap, and by the time you add the right carb/s linkage, fuel system, etc.... You can build a N/A engine much cheaper.

There are some pretty good books out there you should read up on it if you are seriously thinking about it.
 
#9 ·
What I was thinking about is one of the little weiand pro-street type blowers. I have a low mileage rebuilt 4 bolt 350 that came out of my nova and i have been trying to decide what to do with it. It only has about 8-1 compression, but runs great. I was thinking of just adding a mini blower and a blower cam and running it in my '78 1/2 ton. It would probably even fit under the hood with the right air cleaner, and should make lots more low end and midrange than the engine that is in there now (it is getting tired). Supposedly one of these little blowers will add around 100hp or so, which would be perfect.

What books would you recommend on the subject?
 
#11 ·
I just sent Holley's supercharger tech support an e-mail with a bunch of specific questions for my application...curious to see what they come back with.

Rather than start a new topic, I'll just ask this here. Why is it that most cam companies and supercharger companies recommend a single pattern cam for a milder blower application? It seems to me like you would want a little i/e split on the cam to help with the exhaust breathing. The intake side will pretty much take care of itself. I fully understand the need for a wider lsa, but why a single pattern?
 
#12 ·
Where did you see the single pattern cam recommendations. You are right in your thinking. All my research shows a wide lsa 112-114 and usually more exhaust duration and lift. The blower will have no problem filling the cylinders, you want to make sure you get all the "bad/burned" gas out of the cylinder. Typical stock Chevy heads have weak exhaust flow, that's why the most gain when porting stock heads can be made on the exhaust side (meaning if you were only going to do one or the other).
 
#13 ·
Take a look at Lunati's and Crower's line of blower cams...almost all are single patterns. In Holleys supercharger guide, they specifically recommend their Lunati line of cams (of course) and the 1st 3 cams are single patterns. Comp and crane only offer dual pattern blower grinds though.

Considering the relatively poor exhaust flow of the 882 heads I have, I think I would have to go with a dual pattern whether Holley recommends them or not.
 
#14 ·
LOL, of course Holley would recommend the Lunati cam. I agree with you I would run a dual pattern. Even in blower engines with good flowing heads they recommend a dual pattern. You might want to give Engle cams a call.
 
#15 ·
This might sound stupid but there was a mag. test done once that pitted the good old CC 268HE Against the newer high zoot cams in the same range and for mild applications, (which, I think is what we are talking about here), it came out on top down low and IF I recall up to like 4,500 to 4,800 or so rpm...!! Then the high zoot cams took off.. AND I don't see this trend differing even with a blower....

BUT to me a mild engine isn't going to like running above about 5000rpm anyway, blown or not!!! I.E., imho, -- BUILD THE SUCKER FOR GRUNT!!!!!

I personally would go with either a CC 268HE or a Crane 272/272 Energizer but ground on a 112 to 114 center for a setup like being discussed here!!

And I bet for an almost stock motor the Crane 266/210 cam on a 112 to 114 center with a blower will run GREAT with highway gears AND nice tires!! As always, jmho...

Again, I'm talking about MILD motors here, like one, maybe two steps above stock!!!

pdq67

PS., I think all the blower makers say that a stock cast piston motor like a Goodwrench will take 100 to 125 horses like the mini-blowers can put out easy if not rpmm'ed above the mild cam's generally recommended rpm's limits!!
 
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