40 mercury flathead with columbia 2 speed

Swarm

Swarm

Member
Hey got a question that I was hoping to get insight on. I have a chopped 40 merc that has the original drive train. I was gonna have the trans gone through while I have the flathead rebuilt. Might go 10 over with 1:6 valves and a mild cam nothing crazy just a cruiser and put a columbia 2 speed in.
My question is should I just go with a single big 97 stromberg or dual carbs or even a 4 barrel carburetor. This is just a cruiser not a hot rod or anything im going to go crazy in. But I will be driving at sea level in Central valley California up to 7k ft elevation up around bass lake and sometimes shaver lake.
I was even thinking of putting in autotrend efi, but I am wanting to stay traditional and I know that will be thrown out with the efi. What would be a good carburetor set up for this. I am stumped, oh ill be putting on sharp heads and sharp intake...i don't know what to do
 
Since you seem to be spending quite a bit on the whole drivetrain, I would be increasing the cubic inches with more stroke and a bigger bore - which will give you more torque to pull the Columbia in high gear. I'd probably also consider a few performance upgrades - cam, headers, etc.. If it was mine, I'd probably bore it to 3 5/16 and run a 4" Merc stroke crank for 276 cubic inches . . . in the end, there is "no replacement for displacement" - like most other engines. ;)

Since you're up at higher elevations, you'll appreciate more HP and torque with the Columbia - even though you'll still have to take it out of high-gear on steeper inclines.

What actual year/model of engine is in the car? If you want to PM me and then have a conversation (on the phone), no problem.
 
PS: Drop us some pictures of your chopped Merc. I also have a stone stock 40 Merc Coupe (a West Coast car - no rust). Truthfully, I can't stand the body style of a stock Merc coupe, but I REALLY like a nice chopped one! One day I'll have to get this car done - as I have every single piece for it and the metal is really nice.
 
So if I do what all you are saying then I should go with a 2 carb setup then. Its the original 40 flathead that came in this car from the factory. The car needs more metal work and stainless finished. Its gonna be the family hauler
 

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Swarm said:
So if I do what all you are saying then I should go with a 2 carb setup then. Its the original 40 flathead that came in this car from the factory. The car needs more metal work and stainless finished. Its gonna be the family hauler
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The actual induction system pretty much comes down to how you want it to look under the hood. It can run well with a single Rochester, a single Big 97, two regular 97's or a small 4 barrel. Most of us on this site prefer the looks of a dual manifold and dual 97's (regular ones), but I know plenty of guys that run later 4 barrels and are more than happy.

If it was mine, I'd ask myself "what era" and I trying to stick too and not mix/match too many different motifs in the car as a whole. Given the rest of the car, it pretty much looks like a vintage custom to me, so I'd be going with a vintage style in everything I did to the car.

Who is building your engine? Are they recommending Sharp or is that coming from you? For a dual manifold, one of my favorites is the Edelbrock Slingshot - which allows you to run the generator in the stock location. If I was running the Edelbrock Slingshot, I'd probably run Edelbrock block letter heads to match the era (40's).

Lots of ways to go - and a million ways to skin this cat (with as many opinions as you know whats :rolleyes:).

If you want to talk about it, drop me a PM and we can have a chat - will save us BOTH a lot of dang typing. I can help you define some complete engine 'packages' that you might want to consider . . . at least give you some options with varying performance and associated cost levels.

It is important to think about the complete package (including the driveline and usage), before having anybody build you anything . . .

Best of luck,
B&S
 
I don't know if it will make any difference but the early Mercury cars had an integral pinion and drive shaft. This shouldn't affect the installation of a Columbia OD but it can affect the situation if a person wants to change ring & pinion gear ratios. It's getting harder to find the narrow Columbia ODs but there are likely some still out there. It's a good idea to have them updated to make them stronger. This is a good link for info.
http://www.columbiatwospeedparts.com/
 
yeah i bought my other columbia for my 36 that was bulletproofed from the early ford store but the guy who owns the columbia 2speed parts website told me to go to another guy near me for my next columbia that will go in my 40. I think ill go with 3.78 gears, good for the highway and decent for up hill drives in the mountains
 
That is one nice looking car!!!!! I would go with the 2x2 manifold as well. And the larger cubic inches.
 
yup looks like I'm gonna do that, probably a 276 that way I still have a little room for a rebuild later if need be
 
If your Merc has the original block in it, it may be one with the thin steel sleeves. Check the passenger side of the machined surface where the intake fits for a stamped 99T HS.


If you have the HS, you will be better off with the stock bore, removing the sleeves and having the bores cleaned up can lead to thin spots on the bore failing. I would go with the 4" crank and the stock bore, light flywheel and a good street cam.


You will have a long search for a 3.78 ring and pinion with the drive shaft attached. Most 39 & 40 Mercs came from the factory with a 3.54. The exceptions were the ones sold in mountain territory. I haven't found a specification for the 40 Merc's sold with a factory installed Columbia. The pinion gear is part of the drive shaft on the Mercury
 
A little added info on Columbia's and carb's.

The '42-48 Columbia's are better units than the early units. The electric over vacuum shift controls from a '46-48 makes the Columbia's very user friendly. The '42-48 units are two inches wider than the '36-40, using the '40 drive-line and banjo with '37-38 radius bars, will bolt the whole thing together. No machine work or welding. If you can find a '47-48 Columbia it will have built in provisions for a factor sway bar.
For trouble free driving, especially if you drive into higher altitudes, a four barrel is better that multiple carbs. The four barrel should be somewhere around 400 CFM.
 
Hey Swarm, IF you have your 81T heads handy would you mind posting pictures of the temp sender tapped holes (inside the tapped hole) in the heads on each one since you say they are the originals????
 
This is the only picture I have of the engine. I'm currently stuck in the middle east, otherwise I would have been more than happy to snap some pictures for you
 

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TomO said:
If your Merc has the original block in it, it may be one with the thin steel sleeves. Check the passenger side of the machined surface where the intake fits for a stamped 99T HS.


If you have the HS, you will be better off with the stock bore, removing the sleeves and having the bores cleaned up can lead to thin spots on the bore failing. I would go with the 4" crank and the stock bore, light flywheel and a good street cam.


You will have a long search for a 3.78 ring and pinion with the drive shaft attached. Most 39 & 40 Mercs came from the factory with a 3.54. The exceptions were the ones sold in mountain territory. I haven't found a specification for the 40 Merc's sold with a factory installed Columbia. The pinion gear is part of the drive shaft on the Mercury
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Great info thanks
 
blucar said:
A little added info on Columbia's and carb's.

The '42-48 Columbia's are better units than the early units. The electric over vacuum shift controls from a '46-48 makes the Columbia's very user friendly. The '42-48 units are two inches wider than the '36-40, using the '40 drive-line and banjo with '37-38 radius bars, will bolt the whole thing together. No machine work or welding. If you can find a '47-48 Columbia it will have built in provisions for a factor sway bar.
For trouble free driving, especially if you drive into higher altitudes, a four barrel is better that multiple carbs. The four barrel should be somewhere around 400 CFM.
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Appreciate the help with Columbia's and the carb
 
I have a 39/40 Merc Columbia,3:78 ratio. Just measured from flange on the diff where the torque tube would bolt, to end of driveshaft, looks to be 74".
 
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