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  Topic Review (Newest First)
10-07-2005 05:52 PM
Your suggestion about a mild 390 GT build up

Thanks ! Good info.
10-05-2005 06:07 PM
Your suggestion about a mild 390 GT build up

Haven't fussed with a 390 in years, but, the one thing you want to think about really hard is gasoline.

A good modern cam grind can make a lot of power with a lower static cr, and still be good to drive.

The big Ford manifolds won't clear your shock towers, or I'd sell you mine!

What I recall from my '67 GT is that is ran like a scalded rat to about 4800 or so, but the small carb and corked up exhaust kind of flattened it out.

To really run hard, it needs more carb and exhaust (cam's really pretty good) and MUCH better valvetrain. The GT's had non-adjustable rockers and valvespring that were a built in rev limiter.

I'll let someone who's built one in this century take the wheel here. But if you had the dough, it would be hard to beat the Edelbrock Performer RPM system.

The only things for sure to do:

Pick up a set of CJ nut-and-bolt rods, they're stronger than the S- or Z-code stockers, but not much heavier. Get the CJ oil filter adapter and match your block openings to the ports, you get better flow thru the filter. Use a windage tray and the 7-quart 427 pan, that keeps the oil down where it belongs. Get the adjustable rockers and use them with some good valvesprings.

If you're bucks up, you can stroke it to 410 with a CJ crank, or one of the aftermarket strokers. Just make sure all your recip weights are right and the block's not too thin in the walls ( the greater thrust angle can find a soft hole every time).

A 390 will probably never be the king of the street, but you can run anyone hard to 90-100 mph with one. And they look really cool all dressed out.

Good luck
10-03-2005 11:53 PM
Your suggestion about a mild 390 GT build up

It seems like the truck really was waken up ! That kind of performance would be adequate for the GTA.Sorry to bother you with these extra questions but have you got any idea about how much compression did the engine have? Were the heads ported? Was the intake stock? Any idea about the cam part number?
10-03-2005 06:48 PM
Your suggestion about a mild 390 GT build up

well sounds like you got a good thing goin for ya, with the parts you have mentioned, that thing really oughta surprise ya, hell we built a 390 for a friend of mine to put in a 66 ford truck, we just put us a small crane cam in it, to where he could still get away wiht the stock rockers and stuff, bored it .060 and put a 800 holley double pumper on it with a set of 1-7/8 headers and all and it'll run mid 13's in the quarter, thats with a stock c-6 and convertor with a 3.00 gear, damned thing just makes gobs of torque, i was really surprised with how well it actually ran, considering he aint got about 700 bucks in the whole motor/trans combo, yea a FE maybe a dinosaur, but at the same time it dont take much to wake up one of them sleepin giants,
01-21-2005 07:56 PM
Your suggestion about a mild 390 GT build up

The S code 390 engine in my 66 GTA has never been opened. I am planning for a fresh-up job / rebuild and am wondering about compression, cam, intake+ carb and possible headers.
I want to keep this car as much stock appearing as possible without being too strict. It will look stock in and out but I really dont mind having some extra power. Targeted powerband is around 1500-5700 rpm.
The 390 GT engine has 10,5 compression, 270/290 degree cam( same as 428 CJ) and "hi-perf" exhaust manifolds.Ok, they are a slight improvement over the standard 390 log manifolds but not a real hi-perf piece.
As for the intake side, A Edelbrock Performer manifold and a 750-780 vacuum secondaries carb sound like good pieces.
How about the cam ? 10,5 compression with a mild cam and 60s cast iron heads does not sound like too good idea. How good is the stock hiperf cam when compared to modern desins? I would think something like Comp Cams 260-268 Magnum or a mild alternative from their Extreme Energy series would fit the bill nicely.
Have also done a lot of thinking about the exhaust manifolds.I quess the ideal alternative would be a set of real FE high perf parts like the bananas for 63-63 Galaxies but at least those wont fit. Are there any FE shorties available?
I dont want to hear the full length header noice inside the car in this case.
Which combo of parts are you running and are you satisfied?
How would you build the engine ? This car is intended to be a nice comfortable cruiser which should do the quarter in less than 15 secs with radial tires and C6.

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