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I have a 68 Galaxie with a 302 that I'm putting a 351m with a c6 into it. What are some possible performance upgrades for both? I know the cheaper route so far is the valve train, intake, and upgrading to a 4 barrel. As far as the transmission goes I have no idea and for aspiration, turbo v supercharger?
 

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You most likely have a 2.75 or maybe a 3.00 rear gear. Change to say a 3.55 will give you a seat of the pants torque improvement.
 

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Hello,

Just a quick note, if the '68 galaxie 500 originally came with a 302 and FMX transmission, it will have that WER rear axle of which parts are nearly impossible to find sans wheel bearings and seals. To change gears you'll have to find a 9 inch and replace it. 1968 full size with 390's or larger came with heavy duty 9 inch axles, everything below came with the WER. I used to have a 1968 galaxie 500 fastback with a 302 and it had the WER axle and now we have a 1968 XL fastback with a 390 (cheesy Y code) with a heavy duty 9 inch and a 1968 LTD 4 door ugly thing parts car with a 390 Z code and that has a heavy duty Ford 9 inch. However both of those cars came with 2.75 gears. Most 1966 full size came with either a light duty Ford 9 inch or a heavy duty Ford 9 inch and most of those were 3.00 gears. Those axles should fit the '68. I gave two of the 1966 light duty 9 inch axles away last year. But I bet you could call around to places like CTC Auto Ranch or Desert Valley Auto Parts in Arizona and have one shipped to you.

Something to think about.

As for power upgrades you can look at it from two different angle, either getting more fuel and air into the engine to make more power and withcidentally use more fuel, or you can look at it from efficiency and do what you can to lower the power loss in the engine and transmissions. Apparently the C6 has one of the highest parasitic losses (mechanical energy turned to heat internally) of all the large old 3 speed American automatics. You can rollerize the transmission, but honestly I think you'd be better off with a 4R70W (built up if necessary depending on power levels and traction) that way you a wide ratio gear pattern to hopefully match the power band of the camshaft in the 351 (assuming everything else is properly matched) and you can have overdrive with lock up.

Concerning efficiencies in old engines one of the largest energy vampires is the friction of the old style ring packs. Modern engines use modern materials and skinnier rings to reduce drag and free up horsepower as well as efficiency. I have noticed more and more aftermarket pistons using the skinnier ring packs for older engines. Other not so popular engines like the FE require custom made pistons and currently having a set made for our other 1966 galaxie 500 XL. A roller camshaft will lend itself to more of a performance upgrade (assuming you pick the correct profile) as the faster opening and closing rates of the valves allow for more of an aggressive flow without sacrificing low end power. I was able to squeeze just north of 500 gross hp from a 396 (30 over 390) peaking at ~5600 RPM while still getting 15 inches of vacuum at idle to run the factory HVAC system and power brakes, as well as the power rear vent (1966 4 door hardtop). The engine has enough low end torque to spin both rear tyres rather violently at about 1/2 throttle off the line and lots of seat of the pants feel, even with the stock 3.0 gear.

But all that comes at a cost, loads of custom made parts for the engine was about 11K to build up the old cheesy 1966 Y code 390. To rollerize the C6 for average person of buying the parts about 1500. This is not for everyone as everyone has to weigh the cost benefit ratio of their situation.

Good luck.
 
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