I've been working on a buddy that owns a salvage yard that has a 66 tbird and I want the 390, know absolutely no history on the motor. Recently found that a freind of a relative has a somewhat rusted 68 f250 camper special(2 wheel drive) with a 390 running that he is parting out, told me I could have the motor/trans if I wanted it. I have done a little research and the only hard numbers I could come up with say 200hp, the Tbird is 315hp. Does this sound correct? I cant see a half a compression point droping 115hp, or is the rating wrong. Also where is the compression difference, the head or dished pistons. Would I be farther ahead by getting the truck motor and using the heads and intake off the Bird. The bird looks like someone may have partially gone through it ie.. lead plugs in one head I can see, holley carb, and oozing silicone. I'm looking to replace the 352 in my Galaxie with a little more pep. Also wouldn't the trans be a C6, would that be a better option as well (cruise-o-matic) with my 3.00 gear.
the compression difference is in the pistons, they are a lower pin height version and are down in the hole a bit. its a lot more than half a point on the comp ratio. the 66 bird trans is probably a cruise o matic still. i think you're better off with the bird motor, swapping the heads will get you a little better flow over 68 truck heads but with no compression its not worth it.
Your correct on every point,and I would take the heads off that 66,they are better than the 68 heads(same valve size but bigger ports).With the heads off you can see if the pistons go to the top of the bores .Some of those late 360-390 were up to .08 below the deck. That 66 390 would have flat tops (sort of ) about .04 center dish with no valve reliefs.The 67-70 pistons were big dishes and big valve reliefs. Lose those gears...go for some 350s or 370s. Hey what year Galaxie ? I have a 65 XL fastback..good luck with your galaxie,hope to see some pix!
The 66 bird is not a cruise ,its a c-6 (ford part number c meant 1960s ,6 meant last year ... c-6 = 1966 c-4 = 1964
Some early 66 T Birds still came with Cruise a Matic trans. Look at the data plate, code 4 is a C6 trans, code 8 is a cruise a matic. You can also look at production date and the Cruise was fazed out in mid November of 65 (the 66 cars started production in August or September 65)
If I remember it correctly, I believe that a 67 390 with a 2bbl on it was rated at 265 hp. My father had one in a 67 XL. It seemed light years ahead of a 65 that he had with a 352 4bbl.
on the c-4/c-6 the date code of the year of introduction was adapted to be the part #, it wont neccasarily denote the year of manufacture. the c-6 was a late model year introduction, most '66 models still had a cruise o matic. the '67 model year was really when the c-6 became the standard.
You might want to try going to Ford FE .com for any questions about the 352,390 and transmission choices.There are people there that have vast years of F.E. knowledge and can really surprise even the experts here!
Somewhere around 1970, manufacturers started quoting horsepower figures in net horsepower instead of gross horsepower. There was a dramatic decrease in "numbers" without an actual decrease in performance. I wonder if the pickup is rated in net horsepower. Larry T
There is a world of difference in the two engines: Carburetor: T-bird - 4-barrel Truck - 2-barrel Compression: T-bird - 10.5:1 Truck - 8.6:1 Horsepower ratings: T-bird - 315 HP Truck - 255 HP And while I don't have specs readily available, the cams are also different. Jon.
Quote: Originally Posted by RichT in Sanazay The 66 bird is not a cruise ,its a c-6 (ford part number c meant 1960s ,6 meant last year ... c-6 = 1966 c-4 = 1964 "I'm pretty sure that this is incorrect, not that it matters to the OP. I've always known the C4 to be the lighter duty auto trans (separate, removable engine-specific bellhousing, cast iron main case) and the C6 to be the heavy duty trans (bell and main case one piece, with the different cases for different engine bellhousing bolt patterns). I have been wrong before though..." mjlangley Actually, both are correct. The C4 is a lighter duty trans than the C6, and the C4 did come out in 64 with the C6 coming out in 66
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What you said here regarding Ford's parts number system has nothing to do with C4 or C6 transmissions
The 66 T-Bird IS a cruise-o-matic. The C-6 was used in 7 Litre cars and GTA Fairlanes. Full size Fords and Birds got the cruise-o-matic. The cruise-o-matic can be compared to an FMX trans, but the cruise-o-matic has a cast iron case. C-6 became more standard in 1967 ans has an aluminum case.
Check the VIN...."Z" is the 390 "Q" is the 428....they look exactly alike. Go with the Bird engine, several years ago Street Rodder built three of the FE 390s. One was stock spec, one was a mild street hop up and one was an all out thumper. The stock spec (except the compression ratio, 9.5 in order to run pump gas) pulled 298 HP on the dyno through stock exhaust manifolds. Says a lot about the heads and cam for that engine from the factory.
TRANSMISSION CODES 1966 Thunderbird CODE/DESCRIPTION 4 C6 Dual Range (Automatic, 3-Speed) (Installed with all 428 engines, and was used exclusively after mid-November through remainder of production) 8 Cruise-O-Matic (Automatic, 3-Speed) (Installed with 390 engine only in early production, and discontinued in mid-November)
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