I am looking into build my 350 low compression so i can add a blower later on. It will be a daily driver completly street car and I am aiming for 400hp. My question is what compression should I build as a base? I'd like to be able to run my car on premium or super if necessary. My other question is what compression will acheive premium gas or super w/o ANY chance of pinging? PS roots blower clear a 2.5" cowl?

Never mind did some net research cuase the sites search failed me and I found the 142 is optimal for a 350.

you dont need a roots blower to make 400hp

I know that but I'm building a 330-350hp engine and putting a weiand 142 ontop to make around 450-480hp...

I don't know that a 142 will move enough air to support 400 HP.

I'm really not sure I am trying to get this information seeing as how holley's site is quite lacking. So you think that it wont boost my power past 400hp? Is there a reason besides it being a small blower? Whats the next step up...

PS: I am keeping this all under a 2" cowl

It's a small blower intended for adding some power to a stock engine. It'll be hard to find a roots blower that will give you 400 HP and still fit under a 2" cowl.

Why do you want a blower anyway? You can easily do 400 HP NA without all that stuff on top of the engine..

So a roots blower isnt a major power adder like all the other blowers and turbo setups I see? I dont understand its still a blower how does the engine not benefit whether it has 240hp or 350hp? If it is true I think I'll leave my engine at around 300-320 (if I do roller rockers) and blow it for whatever it will give me. I dont mean to doubt your knowledge but saying that it wont boost me past 400hp doesnt make sense to me. More air is more air whether its into a 200hp motor or 350hp motor.

To make big power with a little blower you have to turn them faster. There is a limit to how fast you can spin em and this will generate more heat and be less efficient. You should be able to make your 450 with the blower but I dont think it will fit under a 2 or 2.5 inch cowl(not sure though). Somewhere on this site there is a walk through where a guy put one on his malibu(maybe in the tech articles) you should try to check it out its very informative.

More air is more air, but the question is whether a weenie little roots blower would actually be providing more air.

what about the 177? I read an article on here about how to acheive 500hp with a mild 350 with a 177 ontop...

That would be damon, see the main page of TGO's tech articles section. Basement of 12's IIRC.

I went with 177, still building the motor so I can't say much but I'm sure I'll like the torque it will make.

A couple of links:
Adding a Small Roots Blower for More Power
Danger Mouse Test Engine

you are looking more like a 4" cowl and that might still be not high enough with the 142 on it. i am running a 7" crank pulley with a stock upper pulley and know that my hp is above 450. i am pushing around 7.5psi of boost. if you read up on me and damon you can see are talks on are builds.

check out the new magnuson 122-HH. CHP stuck the little blower on a 400cid and made like 500hp.. rediculous.

I like the bypass valve it has to reduce pumping loss during cruise.


btw if you are going roots for the wow factor... just get a 6-71 and cut a hole in your hood.

If you do a good home porting job on the heads(or good aftermaket heads) the small roots blower 142 will cap out at around 500hp (smallest pulley and fresh blower) to the crank perhaps 480 or so since ideal conditions are rarely met. I would shoot for 7.5 to 1 compression or 8 max, giving you a higher volume of air possible per combustion process (this is key to detonation and optimazing the most power out of a blown motor). The 177 mini blower will allow you to reach 500hp goal with slighly less work on the heads especially at higher rpm, the 142 will produce slighly higher torque numbers down low. One thing never mentioned is that at 400 hp roots blown is NOT at all the same as 400hp on an NA motor. On the street there is no competion, the blown motor WILL be on the power band right now everytime you need it. 400-450 hp on either blower can be achived without trying. I dont recall 100% but i believe the 142 with drop base air cleaner can fit on a 4inch cowl hood with no problems. I didnt have a hood when I played with mine. :-)

I dont recommend a Big 6-71 blower if you have your car as a daily driver. It attracts to much attention and you cant leave it anywhere. Plus no visibility!!!

Put the 142 on you wont be dissapointed. word of advice....start working on your lack of grip now!!!!

Well my machinist tells me that theres no way you can put a "big boy" blower on a street car and run 92 octane. I told him hes wrong and that this blower only boosts compression 1.95:1 and if I build a motor for 7:1 it would be perfect for 92 or 93 octane. He told me to give me motor a run and I'll find that 300-330hp is far more than enough for a daily. I am thinking that once I get a good job I will put a motor on my stand that will surpass any LT1 or gen 1 around my town. I'm thinking in terms of 396 punched 30 with a roots sticking out of the hood. IDK if having that buldge out is illegal in NJ though but I certainly hope not. At that point Ill retire my car to weekend warrior/strip car.

a bbc blown is retarded for killing GenII/ GenIII cars... you can easily do that with a SBC and still have resemblance of gas milage.

As for a 6-71. It can be done on pump gas. it will just be a chore to drive. As for when it rains or you needa leave the car alone in public... get a bigger cowl lol...

shoot you get used to having a cowl stickin in your face and it seems like nothing after the first 2 days

I agree with AFBCamaro and Saigon_Bob exept for the rain part, I have driven in downpours for extended periods of time and have never had a problem....except for the clean up lol....as far as 400 HP that will be easy out of a 142/144 blower and will run fine on 92 if you keep your compression in the 7.5 to low 8 range. As far as hood clearance for what it will help this is a pic of mine back in 86 with a B&M 144 but it had a almost 2" dual carb adapter on it also





if you want to go bigger this is what you end up with lol

I live in Florida and have driven my 6-71 blown camaro in celestial hurricanes and it will not skip a beat so definately not a problem with water.

oh i always thought about the bug catcher taking in water... i guess it doesnt?


you live in Ho-lando.... i gotta check out your car... lemme know i live in stank cloud

LIttle water can get into the catcher (the street types with filters) and what can, with a blower helping beat the hell out of it is no big deal.

Saigon_Bob, You live in St. Cloud but it says on your profile kissimee, I live in Kissimmee but my profile says Orlando. Paranoids!! LOL

Saigon_Bob do you know someone who does good custom exhaust work. I have some 2210 hooker headers and side pipes... I have two cutouts as well and need to have it all installed. Dont have the equipment for this stuff. (I had shorty headers before with no cutouts but the small headers actually do not even cover the exhaust opening of the heads so i had to upgrade. I should be road worthy in about two-three weeks, then the exhaust (running open headers get the cops angry. Ill let you know when I have it running again and Ill contact you, maybe we can talk cars.

Uh if you don't mind driving into kissimmee you might try Road Runner Mufflers on Michigan and Osceola Pkway.... i dont know much of Orlando shops.

yea we can talk cars for sure... i know a lil.. lol graduated from UTI and i work at a car shop so i know the basics lol... well and i helped out at PCC Auto/ Twister Racing Engines machine shop soo... lol ok let me stop.

take my phone number... you can call me anytime after 6pm i guess, no phones at work policy.

407-908-4759
-Alex

Sure man Ill give you a call in about 2-3 weeks when the car is done (well running on the streets). I would go to road runners but the yerks dont want to make custom exhaust, it takes them to much time. They are just after the quick buck, (install a rice burner pipe and off you go).

yea true.. maybe this place in St Cloud... kinda far but my dad got his RAM 1500 done up pretty nicely by them... quick too