It’s obvious in your engine picture that that vacuum booster line simply turns outward and then does a 180 back toward the engine….most assuredly goes to back of carb. Factory routing was just directly inboard to back of carb. So ….it’s not a problem.

As for air conditioning….it was and is, an option. If you don’t need it where you live you are far better off without it. Just a bunch of complexity and garbage to deal with. Besides a Corvette is made with t-tops for a reason……I put 5000 miles a year on mine and about 4500 of those miles , t-tops off and windows down….and it gets hot and humid where I live….no problem.

As for engine power, all it takes is lots of money mostly, and knowledge on what to do to make a lot of power. You will have to spend slot of time learning. It’s not a simple thing. But let me add this. All cars today are fast….old corvettes can be made to be fast, and a Chevy v-8 is one of the most modified engine around. Don’t chase the idea that big HP is mandatory. Consider what you want out of the car, and realize the true joy of this car is in driving it, and experiencing it classic appeal. Any 4 cylinder boosted modern Honda or Subaru will waste you in a race. Improving the torque and HP can be made within some minor changes but don’t expect a 600 hp engine, without lots of money and way more knowledge. It’s not really worth it. If you want to really go fast, you should buy a modern car…..almost any of them. I have have spent ridiculous money chasing torque and HP in my 77, and it certainly has more acceleration than it did with stock 180 hp, but it really doesn’t matter that much on a street car driven responsibly.

 

That fixed fan setup is definitely costing some hp compared to the factory setup Ive seen that fixed type cost upwards of 40hp believe it or not on engine masters fan shootout episode. As far as the carb size 670 is more than enough for most 350s even the factory carb didnt actually deliver more cfm on a stock engine because the engine couldnt pull it or use it. The larger carbs can deliver m a few more peak hp at WOT but at the cost of throttle response everywhere else.
https://drivemag.com/video/cooling-f...-masters-ep-20

 

See, here i gotta disagree with you. Or half disagree. If you want to go really fast, but are not a builder/tuner... then yeah, maybe a new car would be better. If you want to build a really fast car, i honestly cannot think ov a better, cheaper, easier platform for sheer, ridiculous speed, than a C3. They are low, wide, sleek, relatively light, simple (compared to new cars), have a ludicrous aftermarket and tech support, and they come pretty damn impressive... if you can tune a CAR. With little money (again, relative to a new car), they can be FAAAAAR lighter, make 5-600HP with ease, and there is so much suspension and brake upgrade available you wont be able to choose. That also means this stuff ACTUALLY appears used here and there. Someone on FB was just selling a full Vansteel suspension upgrade for little over a grand. My friend just sold a 406cid Brodix headed 500+ engine, built by a famous builder here, for a few grand. Parts EVERYWHERE. Aside from a first gen RX7, i honestly cannot think ov an easier car to straight-up win races witthout going broke. But again... thats if you like to do your own work, and can.

 

People define “fast” in different terms. Your previous posts make it clear that your definition is way way faster than most people, and certainly me. There is nowhere in Western PA that anyone should be driving faster than 80 mph and that really is irresponsible. Most roads are safe at 60 mph in a Corvette…..if you are paying attention and careful. The OP in this thread needs to consider this, and maybe not me worrying about unneeded and useless HP. When people drive on the streets like on a racetrack they risk the lives of everyone around them, and is immature and irresponsible. If I lose a loved one over this nonsense….the fool who did it will pay a steep price. People are dying every day in this country because of junior race boys playing games. I know this is not popular on a Corvette forum…..but the make / model of the car does not change the facts. Or does the irresponsible behavior of the person behind the wheel. That’s why there are speed limit laws.

 

Im just going to point out there are other uses for a fast car... Many take them to the local drag strip on the weekends..And a lot of folks just take them to cruise nights and car shows and enjoy having a fast car without ever actually finding out how fast. I myself prefer the zippy low end torque combined with street drivebility. If speed, power and improved handling at higher speeds (AKA sportscar performance) were not a driving factor behind the corvette or sportcars in general regardless of speed limits, You wouldnt see that as the driving force behind the marketing and you wouldnt see the evolution of the vette to a 600hp mid engine platform.. The reality is people own these cars or any car or truck for different reasons and its just that simple.

 

Yes and the OP needs to decide what HE wants out of the car. And should be realistic about it.

 

power and the makes sense stuff is out the window?
Nobody "needs" to go over the speed limit but knowing you have it under your right foot alone can be a thrill.

Fans may draw a little power but Ive never "felt" the difference from the drivers seat. When it comes to cooling, safety stopping
Ill make a sacrifice somewhere else and leave those systems be.

OP..know most these crates are tested in ideal conditions..140 deg coolant, hot oiil cold air piped in to the carb, dyno headers, no accessories.
So if you want an honest 350hp order a 400hp engine or youll be disappointed.

 

…and reassuring. I recently drove my 2017 Camaro SS thru Chicago traffic for the first time. Knowing I had 455 hp under my right foot and awesome big brakes to get me out of tight spots made the drive much more palatable. Of course, then the stress was paint chips from all the damn construction…

 

Oh, I totally agree with the bold face statement above......my joy of driving the Corvettes I have is NOT about what speed they may be able to attain....its about the fact the first, its an American icon, one that I wanted most of my life, till I could finally afford it in my late 50's. Secondly,....I do like acceleration, the sound of an American V8 engine through a great exhaust system, the great handling the cars have on the twisties I drive on,.....and the fact that I built the car better than Chevy did. Going excessive speeds is NOT on my list.....because a Corvette is NOT something special in that regard. ALL cars today go fast....and most people drive fast.....irresponsibly, without regard for others. And as a result....people die, innocent people. Speed matters on a race track. So.....again....the OP is asking a question about HP improvements. I have made LOTs of improvements on my 77 with the 406 SBC, and will on the 69 with the VortecPro big block........but I will NEVER use the power to its potential. Nothing wrong with that for me, or the OP.....its just a matter of understanding that much of the potential will never be used. I am okay with that. If the OP, or others, plan to race on a track...then, by all means, it matters.

 

I agree. I know it's just me but those flex fans give me the heebie-jeebies, always looked at those as being spinning razor blades. A correct clutch and fan blade would be in my future.

 

Only safe flex Ive used is the black plastic flexalite.
Weigh a few oz..you will never break a blade on one .
Quiet for a flex and move plenty of air. Had a clutch fan let go and take part of the water pump with it did a number on my hood.
BB chevy hitting passing gear..made an expensive noise

I wish..somoene would do a clutch fan with a plastic blade for our chevys Id be first in line.
Make it adjustable (temps)

 

Not likely though due to electric fans kinda making that idea obsolete... I realize there would still be a market for the nostalgia and simplicity though.. kinda like points vs solid state electronic ignition systems

 

100% agree!

 

Why not an Electric Fan setup?

 

One way to look at it is, the more you have... power, performance... the less you have to use it. No different than being a 220lb weightlifting black belt. Its nice walking around knowing that if you NEED performance, you have it. Further, the more you have, the easier your car does average, or above average things. And there are indeed many times when you do need to go over the speed limit, sometimes not just a little. I'm not talking 'schooling Mustangboi' either. A stock 68-70 anything Vette, pre-75 L82 vette, or post 79 Vette, in good tune and real tires, should be able to get around anything or past anything it needs to in traffic, or in the canyons. That should be the minimum. I had no idea how important this was until i'd driven other peoples cars, or rentals (back in the day). Could not pass a dangerous truck. Could not survive a true emergency braking. Could not out-deke a sudden spill on the highway or some dipshit being a dipshit. I even had a case one time, driving a rented Yaris (whatever the hell that is) on Toronto's 401. I was in the middle ov like, 6 lanes, and there were maybe 5 cars TOTAL in sight. So complete jerkoff roars up behind me, and tailgates... aggressively. I am literally the ONLY one on the highway, in 6 lanes. The ONLY thing to do in this scenario was outdrive him, leave the ***** behind and get on with my day. Well, except maybe stopping to fight. Well... i COULDN'T. That woke me up. This world is quite literally too shitty and stupid to not be prepared... WELL prepared (see 220lb weightlifting black belt above...). You dont need a 2017 ZR1, but its nice to have capacity. The more you have, the less stress on the car, and the more probability ov success you have in navigating lifes bullshit. If you're TRULY safety-minded, as Corvettepassion is, then that is very important. I'm daily driving an ill-handling 115HP minitruck now, an older one, while i sort this Corvette bullshit out, and i'm back in that hell, and i hate it. I wont even take it on the highway.

 

And I agree that excess capacity or quality is a good goal. It is essentially the reasoning behind most of my decisions on rebuilding both the 77 before, and the 69 now. But my purpose is not to use it for excess speed, it is for reliability. If I choose to build the engine / car with high quality components meant for high levels of performance,.....then it seems to me that it will be very reliable under lesser stresses, speeds, etc. It essentially provides a safety margin, much like aircraft component design that is always built with large factors of safey margins....ie. built much stronger than needed under normal, and even abnormal use. The upside is that I also have excess capacity for short bursts of acceleration,.....which is one big fun factor for me in these cars. I also just like to buy and own quality components in my cars and motorcycle. As some of you followed, my 406 engine was built will many top notch parts.....some of the best in the industry, and it is very unfortunate that the builder made so many mistakes.......I had the right idea on parts....selected the wrong builder.

So to the OP original questions.......I recommend focusing more on quality parts and quality workmanship, and less about building HP and torque to some arbitrary number. It is very easy to build more than 180 HP into a small block Chevy.....there is countless ways and countless parts to easily make way more than that.....BUT.....don't get caught up in dyno numbers and bar stool bravado trying to beat all your friends and idiots in Honda Civics on the highway.....THAT is my point. Focus on quality, and accept whatever numbers you end up with knowing you have a strong, reliable and well built engine. And remember.......there will ALWAYS be someone with a stronger engine....because ALL it takes to make ridiculous power is MONEY. Its not a fair contest. I have posted several threads over the years asking for recommendations on a build,....mostly trying to build a quality engine.....and many of the existing and previous race boy posters here continuously crank up the narrative with bigger heads, bigger cams, bigger displacement till the only thing a guy could do is spend all his money building a monster motor.......so, you have to ignore all that, and find your own place.

 

^ What always gets me is how many people get caught up in the hype to make big HP numbers which on a sbc 350 typically results in an engine thats a no fun to drive on the street unless you change out the rear gears converter if its an auto. They often end up disappointed and sell the car... People mistake torque for hp. back in the 70s car and driver rated the L48 corvette as more peppy and fun to drive on the street than the l82 because the l48 has more low end torque which really helps get the car moving with the gears these cars came with. While theres plenty of room for improvement at both ends its easy to get carried away with a huge cam and an engine built to make its power at rpms the owners often will never really see... all for bragging rights in many cases.

 

They are great, I love mine. but they are more of a modern design like fuel injection that these cars didnt come with and some folks prefer to keep it old school. and depending on what era a person started turning wrenches often determines what they are most comfortable with... Plus there were lots of incorrect assumptions and shadetree mods made popular by word of mouth at different times and there was a time fixed flex fans were the rage. they look fast and that matters more than actual performance to some folks.

My uncles 76 came with incorrectly installed poor quality electric fans that ran 100% of the time (which also give them a bad rap) and his friends installed a fixed flex fan which made it even worse as far as overheating... In the end the best choice for him was for me to find the correct clutch fan and add the shroud seals. I should have just installed better electric fans but then I would have needed to update his electrical setup to handle it and well I have my own car to build.

Wow we really took the OPs thread off the rails with all this... Sorry OP!
I am not sure if its been mentioned but you can also do a compression test which will give you an indication of not only health but also combustion chamber upgrades.

 

Why try to out engineer the GM engineer? A property installed and operating OEM cooling system works just fine.

 

I agree 100%, with the caveat that if you seriously increase horsepower, you will need to enhance the OEM setup. I’m not talking reinventing the whole system, but perhaps a larger radiator is appropriate.