3 deuce intake for staight 8, update

[Bob]

Aaron has sent me some pictures of a straight 8 manifold he x-sectioned. He thought someone might like to use them for reference. You will now be able to find them in the Buicks.net shop at:

http://www.buicks.net/shop/reference/str8_xsection.html

Thanks!

[53Special2]

/Users/Castillo/Pictures/iPhoto Library/Originals/2009/Roll 137/!BV6WE9gCGk~$(KGrHgoOKkEEjlLm(0GPBKU53vkqKQ~~_1.JP G

[presten]

I may be a bit late on this thread but will put my oar in and row anyway. I have just finished building a heated (very important by the way for a street car) four carb manifold for my modified 320. So far it appears to run very well on the test stand with terrific off idle acceleration with no hesitation or stumbling. I used Holly-Weber 2 throat progressives from Ford V-6 small pickups. I have used these on modified Chevrolet engines in both two and three carb setups with great success. It gives you kind of the best of both worlds with smaller venturi for cruise and then bigger secondaries when you crack the throttle over 3/4. Also they are very easy to jet and adjust.. If anyone is interested in further details on this setup, contact me at presten@comcast.net.

I have since built a three carb version of my original design. This is out of aluminum, uses the same carbs and linkage, same heating system but with one less carb. Here is a picture of it as well..minus carbs. It was a bit more expensive to build since I had to have it professionally TIG welded but it is lots lighter and still cool looking!

[krinkov58]

Awesome! Hot water heated?

[39CENT]

I think you have a good combo there, with progressive throttles and heated manifold, which keeps the fuel in suspension.

[presten]

Yes it is heated by hot water. I simply tapped into the hot water supply for the car heater right at the water pump and returned by the heater return fitting. Simple tees do the job. By the way, I have been made a true believer in manifold heat by Tom Langdon, a former engineer in the GM Engine Division who now owns a company that supplies hot rod parts for GMC and Chev engines. He says that every case of stumble or hesitation off idle he has helped with was cured by heat! Otherwise the fuel simply pools in the bottom of the plenum. I got the hot water heat by welding 3/4 by 3/4 angle full length to the bottom of the plenum chamber to make a triangle shape channel. That forms a nice channel where the hot water can apply heat directly to the bottom of the plenum and never gets too hot like it can happen with exhaust heat unless it is controlled by some kind of baffle or valve. The water goes in one tube and then I loop the opposite end tubes to bring the water back the other way in the other channel. Simple but effective. I start getting heat within about 2 minutes of starting the engine...long before the thermostat opens. The only regret that I have was that I wish I was a better aluminum welder and I would have made it out of aluminum!! Much lighter. As much as I have tried, when I weld aluminum it looks like I put it on with a butter knife!

Addendum: I have since found a good guy to build me an aluminum version of this manifold and went to 3 carbs since the clearance on the back carb to the firewall was not very good. The aluminum version also has the same hot water sytem and work very well!

[markyboy64]

Going way back to the first entry in this thread regarding unequal runners creating leaner mixtures towards the outer cylinders. I'm wondering if the designers of old knew something back then that's been overlooked?
From my experience with multi cylinder race bikes, centre cylinders are often jetted richer to deal with overheating issues. Easy to achieve with multiple carbs.
But how do you do it with only one carby? It's possible that the "leaner outer cylinders" might be viewed as richer inner cylinders to average out cylinder temperatures.
Any thoughts ???

[39CENT]

thoughts on manifolds. -- Buick stock 2 carb intake, heat risors are under each carb. I have heard there was one man heading the development of the dual carb Buick intake, and also was involved with the 4 barrels. I think there was a lot of thought on these at GM. My 2 carb runs silky smooth, and you can hear and feel it come on just like a 4 barrel. The one thing about Buick intakes is thier radical 90 deg. bends. The only reason for them maybe is that a wet flow fans out against a 'wall' which is what those turns are. Most aftermarket inline manifolds have 90 deg. turns, however Packard made a nice curved runner intake, and also nice exhaust manifold. 37 and earlier Buicks had curved intake runners, 35 and earlier heads had tapered ports into the combustion chamber., so many different designs---

[gtopite1]

I just pulled my str8 from my 1950 Special and am getting ready for it to head to the shop. I am looking for a different intake and exhaust manifold set-up. I was checking out the multi-card red intake, and I did like it. Has anyone made a new intake or had any new successes in the str8 modification land. I am looking for ideas before starting my rebuild. I know I saw a post where someone was fabricating a new piston for the 248, and seeing as I am about to rebuild one, any new mod info is awesome. Please let us know what new pieces have been added to the list. It has been sometime since anything new has come up. Either that or there is a loop in which I am way out of.

[presten]

I understand your pain....there just isn't a lot of off-the-shelf stuff out there for Buick 8's. There are several things however that you can do especially if you plan to rebuild the engine. These are pretty much "boiler plate" mods and have been tried and true on engines of all sizes and shape. First of all, go to a good piston maker and have them build you a set of forged aluminum pistons to get the compression ratio out of the dark ages! Look for something around 9 to 1 or so. While you are at it, look at boring at least .080 over stock size. You may have to run premium gas as the shape of the combustion chamber is not optimum for lower octane gas at that compression ratio but it is well worth it! Next to more cubic inches, compression ratio is probably one of the biggest factors in making power. Second is to get a different cam ground with a little more lift and duration. There are several good cam grinders around that can help you select a grind based on the mods to the engine and the kind of use it will get. An updated electronic ignition is a low cost but good investment and there are some that will even work with 6 volt if you plan to stay with that. While you have the head off, now is the time to put in hardened valve seats and put a nice polish on the valve heads. If you have the time and inclination...polish out the intake ports at least and the exhaust ports if you are not sick of being coated with black grinding residue by then.

Now comes the part you were asking about...the intake and exhaust system. The exhaust system is easy as there are some excellent custom header manufactures out there that will build you a set. The intake manifold is a bit more to deal with. If you scroll up on this thread you will see the one I made for a steel 4 carb setup and an aluminum 3 carb version. That 4 carb version may be a bit much for your engine but the same design using three of those progressive two throats on a custom built (aluminum is nicer) manifold would do the job quite nicely. I would strongly suggest using the hot water heat system on it since your headers will not generally have a connection to heat the intake manifold like on a factory set. An unheated intake manifold is not a very fun thing to drive on the street. Depending on how far you want to push this project you can look at a modification to the oil system for a full flow filter system, shot peen the rods, final balance of the engine and of course, a beautiful paint job on the block and head!
If you would like me to recommend some suppliers for the parts I have mentioned, send me an email direct to "presten@comcast.net" and I will make some suggestions. I don't like to put specific dealers into a forum response. (some people get a bit miffed if you don't mention them)