Questions regarding the 390 GT engine and build options? - Vintage Mustang Forums

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post #1 of 6 (permalink) Old 02-25-2005, 06:46 PM Thread Starter
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Its a little ways down the road, but I saw this article and it got me interested in exploring my options.

My car currently has a 289 so I will have to start from scratch to put a 390 back in it. I thought I would pose a few questions to the experts here and start planning from there. Im hoping to learn the basics of building a 390 up from scratch with EFI, and whether it would be affordable or a huge financial endeavour

1) As I understand it, there are 2 different types of 390s produced by Ford, a 390 GT engine and a normal 390. What are the differences between the two and would it matter which I started with, if I wasn't trying to build a stock engine? If it does matter, what models/years were equipped with that 390GT engine

2) What would probably be the most cost effective way to do it? Buy a remanufactured complete engine (like from Jasper), look for a used engine from a scrapyard to rebuild, or buy a block from a place like DSC Motorsports and purchase components individually and assemble myself?

I searched several different phrases but all the answers seem to be one step past my knowledge level.
Thanks in advance for any help.

1967 Mustang Coupe
Too many ideas to fit in one car

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post #2 of 6 (permalink) Old 02-25-2005, 06:59 PM
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The 390 "GT" engine had the same camshaft from the factory as the 428CJ,,heads were of the C8AE-H variety,,,nothing special,,just drilled for the 14-bolt exhaust pattern,,,blocks were garden variety with flat-top pistons to give around 1o.5:1 compression. Full size car blocks are the same,,,but the better 390 blocks to get are the truck blocks with the ribs down the outside of the block,,,i believe they have a D4TE casting,,cranks are generic,,,but put a 428 crank and rods in a 390,,and that takes it to 410 cubes,,kinda stroker.Thats what i have in my 69 S-code Mach.Buy the Edelbrock aluminum heads from Jegs,,,bolt them on out of the box,,with a alum. intake too,,and either headers,or 428 CJ exhaust manifolds and a hot cam and electronic ignition with a 3:25 Posi gear,,and you will have one hell of a powerhouse.Just BE SURE to drill the oil passage in the block from the pump to filter adaptor to at least3/8 or bigger,,,this hole is only 1/4 inches,,and is the reason a FE wont last at high revs,,,also #1 main bearing doesn't line up it's oil hole on the block side,,you have to chamfer that gallery hole a little to make it line up.ALL those FE's were like that from the factory.Hope this helps. Jeff K.

Professionally restoring 65-73 Mustangs,,Full-size Fords,,,AND 67-81 General Motors Firebird,,,Trans-Am.Located in Simpsonville Ky.,Shelby County.25 years experience,,,,,with emphasis on building beautiful and unusual musclecars,,to include full-size too.Advice and questions are always welcome. (502) 338-1218 Thanks.
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post #3 of 6 (permalink) Old 02-25-2005, 11:58 PM
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First of all, start with a budget. Saaaaaaaayyyy $5500. :rofl:

Now take that budget and DOUBLE IT! Been here, doin it, and the t-shirt ("FEAR begins with FE!") is in the mail.

DSC is a great place to start. Fortunatly, (or unfortunatly), he's 10 minutes from my place! Tell him Jim sent ya! :joker:

P.S. FE and Affordable DO NOT go hand in hand. Make sure your wife gets ANYTHING she wants before you start, or you'll never here the end of it. (SWMBO got herself an '02 T-bird!)

P.P.S. I don't fit in the T-bird.

1968 GT/CS S-code Resto-Mod in process.
416 cid w/ported Ed heads, Crower 280HDP cam, Blue Thunder intake, etc!!

Heeeerrrre cheby, cheby, cheby!
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post #4 of 6 (permalink) Old 02-26-2005, 03:04 AM
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If you go the 410 route with the 428 crank, make sure you use the 410 pistons. With out them the longer 428 stroke will cause the 390 pistons to strike the cylinder head. You could also use low compression 8.5 to 1 390 truck pistons. I went with the Ross forged 410 racing pistons for my 416(.30 over 410) they're pricey and over kill, but what the heck you only live once.
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post #5 of 6 (permalink) Old 02-26-2005, 08:06 AM Thread Starter
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Thanks for the responses. This certainly does clear up some things for me. When it comes time, I will see if I can buy the parts separately as money permits and assemble myself.

1967 Mustang Coupe
Too many ideas to fit in one car

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post #6 of 6 (permalink) Old 02-28-2005, 09:08 AM
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In addition to the engine itself you will also need all the brackets and mounts, the correct transmission, the correct radiator, driveshaft and rear end. ALL of these parts are different on a big-block.

The CHEAPEST way to go would be to find a complete big-block Mustang or Cougar and pull everything off of it. You could probably find a non-running example for about $5K. Then you would have most of the parts. You will NOT save any money by trying to buy all this stuff one piece at a time.

If you can do it for less than $10K my hat will be off to you. When I bought my 68 big-block vert it had a small-block drivetrain in it, so I'm doing the same thing you are. I'm figuring about $15-20K to get a built big-block drivetrain in it, but I'm going with a turnkey stroker motor.

I know that you don't want to hear this, but it would be cheaper to sell your car and buy a running big-block car. It's almost impossible to rebuild an FE motor for less than $5K and that's just the motor.

John Bednorz

1967 Shelby GT350, dark green, 347 stroker, 5-speed, inboards, #2206
1973 Mustang Convertible, white/white, black stripes, Q-code (351C-4V), ram air.
1968 1/2 428 CJ convertible, R-code, red/deluxe red, auto, finally finished.
"If you find the car of your dreams, ignore the price guides and pay whatever you have to in order to get it."
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