Crisdimel1

Supercharged 401?

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Hello all,

I am looking for information on supercharging a 401 nailhead. I cannot find much beyond pictures of engines. I would like to use a 4-71 or a 6-71. Where can I find engine components? What kind of HP can be achieved? Is there anyone that you would recommendto build a motor like this? Any information will be greatly appreciated.

Thank you

Dirk

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Dan,

Thank you. I guess there is not very much info available and fewer people that build nailheads. I will give him a try.

Dirk

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Try the nailhead forum at V8Buick.com. There are a couple of guys with super/turbo buicks and lots of good information.

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IF you really want something period-correct AND might not need a big hole in the hood, research Latham superchargers. They were mainly in the later 1950s and were "turbine-style", as I recall. Lower boost levels but also didn't heat the intake charge as much as the GMC blowers did. Used side-draft carbs to generally fit under a stock hood.

OR . . . you could emulate the still-born Buick turbo 401 for the '62 Wildcat, which didn't happen. One of those prototypes is on an engine stand somewhere in MI, but used to be at the Flint North Engine Plant, for display.

What trans are you going to use?

Enjoy!

NTX5467

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ONE thing to remember about supercharging or turbocharging is that the base mechanical compression ratio of the engine will need to be about 8.0 to 1, rather than the more-normal, naturally-aspirated motor's 9.0+ to 1. The base mechanical compression ratio might start out at 8.0 to 1, but "the huffer" will stuff enough cylinder pressure into the motor to let it "think" it's got more compression.

Modern engines get around this situation with a combination of sophisticated electronics, combustion chamber design differences, and blowers that don't "boost" unless they were needed to "boost". MUCH different from just "bolt-on and go", as used to happen when the 401s were new.

Enjoy!

NTX5467

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You can do a search on you tube for modified 401 with corvette supercharger and it's shown running. local street rod shop did the car. I was at the initial dyno test of 401 naturally aspirated with tri-power b4 blower manifold was fabricated. Eng builder used Chev pistons and rods,lowered compression in anticipation of blower, ported heads and beat factory numbers on the dyno. Was sent some dyno numbers, but I'll have to see if I can find where they are now. Hmmm? custom profile on cam(read secret)

Hello all,

I am looking for information on supercharging a 401 nailhead. I cannot find much beyond pictures of engines. I would like to use a 4-71 or a 6-71. Where can I find engine components? What kind of HP can be achieved? Is there anyone that you would recommendto build a motor like this? Any information will be greatly appreciated.

Thank you

Dirk

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Look for the you tube video. the mans name is Guy Henson. Last I heard he worked for Ravenworks in Plymouth, MN a suburb of MPLS MN. I asked about the specs, but he was not willing to provide them. I believe he used big blk chev forged alm rods and they had to be narrowed to fit on the crank pins of the 401, however, this gave him a wide array of pistons, stock and aftermarket that were much cheaper than resorting to custom pistons for the stock buick rods. His partner Tom did the porting on the heads. Guy specd' the custom profile on the cam. His customers can afford to pay for one off modifications, as evidenced by the nice blower manifold they designed and built for the 401. I don't know how to post links, but I can try and find the file I saved the you tube video in and attach to an email. The dyno run was a bizarre competition, where two highly regarded builders were both paid to build for a dyno test, with the winners build going in a 1940 Ford 2dr street rod with the Corvette whipple blower. Done and done! I will hunt up more pics and details as I can, but specs I don't believe will be available, considering the client for the build doesn't care to have that expensive info disseminated for free, or I'd be building mine that way already! The old saying "speed's expensive, how fast do you want to go".

Edited by 2carb40 (see edit history)

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Found dyno video again. posted by Oldcarwiring guy. shop is CCR. in Blaine, MN. You can talk to the owner of the shop Jim @ 612-209-7346. The client is very concerned about personal privacy, so I would appreciate line of questioning to specs not identifying who owner of car is, thanx. If you can't find video, you can PM your email to me and I can send as attachment

Edited by 2carb40 (see edit history)

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Thanks for the updates and information.

The reason I was wondering about pistons and rods was that I know that a piston (or piston ring) does not know which engine it'll end up in, provided the size is the same. Bore size was a main question (even an oversize of a standard bore that would, or COULD, be used in the Buick, even if it was not a different end-size than a normal Buick oversize bore size), with rod length and compression height being the next specs I was wondering about. End result is that if a Chevy size or rod length might work in what they were trying to do, having "available blanks" to build these things from would certainly be an advantage. Narrowing the rods with different piston pin diameters would be more "machining operations" than "custom build" situations. Having existing piston blanks to work with would certainly be a consideration IF lighter-weight pistons were desired (with lighter-weight piston pins, too).

When the 401s were new, there were LOTS of custom pistons and alum rods available for them. They WERE considered to be a good alternative for "power" engines, as TV Tommy Ivo proved with his Buick-engine dragsters. Then, too, this was when starting with a large-displacement factory engine was a plus for any engine swap situation (as the beloved Chevy V-8 hadn't grown past 327cid back then (although I have a HOT ROD magazine article on building a 400cid engine from a 283 Chevy V-8 . . . all custom stuff well before the later 400cid small blocks were built . . . but with an existing architecture of parts to work from). This was in an era when the largest factory V-8s were generally considered to be the best starting point for a serious hot rod engine . . . with the Chrysler Hemi V-8s being especially desired from the regional wrecking yards. Other "luxury brands" engines also had their place in this whole situation, too (i.e., Cadillacs, Oldsmobiles, Pontiacs, Lincolns) PLUS the transmissions and rear axles which were used with them, too.

Those were my main curiousities, from an engineering point of view rather than trying to scoop "trade secrets" as I know that in such higher-end builds, it's much more about "execution" than about basic specs, by observation. PLUS being able to use "existing items" as starting points, when possible, rather than "wheel reinvention".

Enjoy!

NTX5467

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this is a very cool project, but to do it right would be very expensive. Turbos are becoming stock items for most new cars for obvious reasons and they have them pretty much down pat. You can shove more gas and air into any engine, but to have it stand up to the heat, pressure and keep the mixture correct will take some major work. Old turbos had terrible lag and really didn't boost much. Newer ones are amazing but what he had to put into that project was quite a feat- a bit beyond what I would be willing to invest but definitely fun to follow. Modern engines are so much lighter and all the engineering has been done, but a 425 is such a cool engine

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Well it has been a while since I have started this thread and am just now getting this off the ground so to speak. The motor is out of the car and stripped. The block is clean and deburred, the heads stripped and blasted. Everything is in decent shape so I have a good block/heads to start with. I have spoken to Russ Martin and I am talking to Mike Lewis about porting. Because I am using forced induction I am going to port the exhaust side and not spend a lot of money on the intake side. My compression ratio will be right around 8:1 and I will be using forged Ross pistons. I am going to convert a 6-71 from its original diesel blower configuration over to be able to create boost on a gas engine. I am planning on 5-7lbs of boost.

On a seperate note I will be selling the parts I will not be using. What is a fair price for 1965-1966 factory 425 2x4 intake manifold worth? It has carbs but I believe they are not correct for 425 2x4 set up. They are two 1965 single four barrel carbs. I can't find a 2x4 manifold for sale so have no idea what it's worth.

Thanks

Dirk

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Thought it might be time for an update. I have changed the build a little bit but nothing too major. My heads are currently with Mike Lewis of Pro Tech. I bit the bullet and am having him do his stage 3 package. New Manley 11/32 stem valves to increase the flow and he is focusing on maximizing the exhaust flow. He is also port matching the supercharger manifold as well. I have decided to go with a full roller cam. I have purchased the cam blank and am talking to the grinders about the specs. We can't finalize the grind until I have the flow numbers from the heads. I am going to use hyd roller lifters and roller rockers. I have talked to the guys at alkydigger about the supercharger snout, pulleys, etc and possibly putting a EFI system on the motor. Just not sure I can afford that!!! But I am not in a rush to finish this so I may just take the time and save more money for it. We will see..

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Yes, I have made some but not a lot of progress. Mike is in the final stages of finishing my heads. I have the roller cam blank in my possession as well as roller rockers and roller lifters. I have a lot of concerns with the stock crank and rods. The rods are a fairly simple issue to solve. Aluminum and steel rods are readily available IF I have the rod journals ground to the 2.2 big block Chevy dia. A blower crank drive is also next to impossible to find for a Buick. The stock riveted balancer can be machined and modified but I think I'm going a different direction. I'm also not sure just how much the crank itself can take. I would hate to build this motor and lose the bottom end.. So I have contacted a few companies about making a billet crankshaft. This solves a lot of issues. I will have the journals made to the BB Chevy dia and change the crank nose to Chevy. The crank will also be made to be internal balanced instead of external. I'm looking at a 4-5 month lead time for the crank to be made. I realize this is no longer a "true" nailhead motor but this was never my goal. Finding out how much power/torque can be made with a 401 is my goal. 

 I also found a wrecked Cadillac CTS-V super cheap and will be putting the interior into the ole 65 Riviera. 

 Dirk

Edited by Crisdimel1 (see edit history)

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On Saturday, November 29, 2014 at 0:15 PM, NTX5467 said:

Thanks for the updates and information.

The reason I was wondering about pistons and rods was that I know that a piston (or piston ring) does not know which engine it'll end up in, provided the size is the same.

NTX5467

Here's an FYI for all you nailhead junkies.  The bore diameters are the same for the nailhead 401 and the Buick 430, and the nailhead 425 and the Buick 455.  Only the strokes are different.  The rings are the exactly the same/configuration.  So if you can't find those 0.030" over 401 rings, look for some 0.030" over 430 rings.  :D

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