248 straight 8 power

3

37special

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I am working on my Special's 248 inch straight 8 by adding some custom parts. I have a Buick compound carb manifold that I am using with two new 38mm 2 barrel Webers (the nonprogressive type carbs) and 2 custom built adaptors to make the connections. I plan to make two cover plates for the heat cavities under the manifold and plumb them up for water circulation to aid street use. I will fabricate a tube header that is an 8 into 2 into 1 set-up with a 3 inch exhaust all the way to the rear of the car. :D I plan to deck the block, shave the head, and install the thin, metal type head gasket to get a safe 8:1 comp. ratio. I have a set of mid 1940s NOS pistons to help also. Of coarse, the head will get a mild port job with slightly larger BBC valves and hardened exhaust seats. I would appreciate any refferals as to a porting specialist who has experience with the Buick 8s. The stock cam will get a performance regrind once I can find the correct specs.
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Wow! You took the words str8 out of my mouth! That's pretty much what I'm working on. What are you using for a manifold? Is it original? Also where are you getting your headers done? Or parts? I'd also love to see some pics of the motor! I can't help you with the porting specialist, But Terrill Machine (De Leon TX) is a good source for parts and Maybe info. His number is (254) 893-2610

Mark
 
Mark,

My name is Mark too, by the way. The manifold is stock and will remain that way. The parts I will add will be bolt-on. I will have to mill the two heat areas that mated to the original, non existant exhaust manifolds to get a watertight seal. I'm not sure how necessary it is to get heat in there but I'm sure it can't hurt driveability, especially on cooler evenings.
The header will be custom made by myself. Headers by Ed sells preformed J-bent tubes and pipe in various diameters, bend radii, and thickness to make just about whatever you choose.
The engine is disassembled now while I work on the chassis. I will continue work on the engine once the chassis is complete (hopefully by fall of this year). I'd be happy to share any info with you.
By the way, let me know if you need a set of pistons. I have two sets of NOS .030 over replacements with two different styles of crowns to replace the stock flat tops of the '37. I haven't decided yet which set I am going to use, but I would make you a fair deal on the unused set. I should know within a month or so.
You can see the car on my homepage that should be listed in my profile.
 
Heat to the from the exhaust manifold to the intake manifold is strickly for faster smoother running before the engine is warmed up. The heat riser on the exhaust manifold places a resriction on the flow of gases forcing them through the passage under the carberator warming that area. Once the engine temperature rises a bit, the riser opens allowing free flow to the exhaust system.

When eliminating this, you will notice that the car will run rougher on start up and will need a little more "playing with" until it will settle on the fast idle of the choke. Not much of a problem, it is popular to plug the "cross over" on a v-8 on a performance minded engine.
 
Thanks Mark, but I've already rebuilt my motor using parts from Terrill. It runs great but my manifold had some major vacuum leaks which I've patched with weld. I'm not sure how long this will hold, so I'm considering building my own, based on the Edmunds(I think) dual carb setup.

Bob, The only thing that bothers me about not having the heat to the manifold is that on the str8's, the manifold sits awy from the engine. On the V8's after the engine heats up, it provides heat to the manifold so you don't need the crossover as much. If the temp is 60deg or less you can get carburetor icing. I had this happen on a VW, in Ireland, and it drove me nuts trying to find the source of my problem, until one morning I yanked off the air cleaner fast enough to see a golf ball sized chunk of ice sitting on top of the carb. It melted in seconds as I watched! I found out that the heat tube to the exhaust was missing. Once I replaced it I never had the problem again.

Mark
 
You do get carberator iceing, but that is not why. It is related to the outside air temprature and the velocity of the air moving through your venturies. The way to stop it is by regulating the incoming air tempreture. This is normally done on stock aircleaners with a flapper that uses some air from the outside of the exhaust manifold and piped into the air snorkle. When you go to full throttle the flap valve is opened for cold air. So you are most likely to run into the problem with things like open element air filters or flipping the tops etc.
 
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