Need Some Engine Help

Mach1 Cobra Jet · 03-15-2002, 11:36 AM

I have a few questions for some of you FORD Mustang guru's. I have a 69 Mach 1 that I am restoring. I have a 390 Motor and want to put a 428 Crank in it and 428 heads. Will this work and do you know of what other modifications I may need to make to make this work. The motor is from a donor pickup. I don't know what to expect from the stock heads. Also I think the headers would fit fine and all I would have to do is switch motor mounts and get a drop down bracket for the power steering. The car was originally a 351W which is long gone. I am also looking for a top loader 4 speed for the 390 if you know of anything. Any help greatly appreciated.

Thanks, David

mean81GT · 03-15-2002, 11:49 AM

we are doing the exact same thing with our 70 fastback. Here is the info i have.

390 block
CJ 428 heads ( we are going with aluminum repro's from Summit)
428 crank, rods, pistons, rings (all in one kit from PAW)

as far as the toploader, we are trying to find one too...sorry.

if you have any other questions, i'll see what i can answer.

thunderbolt · 03-15-2002, 11:53 AM

That swap gets you to a 406. (not counting overbore) I am not sure if the pickup 390 was the same as the truck 390 (sometimes called the 391) but the latter has a slightly different size front bearing on the crank. (think this is right, front snout or something here, truck versions were larger than car versions and can be turned down to fit) If you find a 391 it can be bored to 428 specs and fitted with the crank. Not sure if you can bore it again.
Are the heads for the 390 different than the 428? I don't remember, seems to me like they were the same. I know you are not supposed to swap big valve versions onto 352's.
As you can tell I am no expert on FE engines but hope this gives you some help. That book "Ford High Proformance" has a large section on FE engines.

PKRWUD · 03-15-2002, 12:05 PM

I can't help much, but I'll share what I know. Except for the CJ 428 and the SCJ 428, 428 heads are the same as 390 heads. The 390 and 428 blocks are pretty much the same (except for the bore), and the rods are the same. Swapping a 428 crank into a 390 would work with either set of rods, but would require special pistons, depending on how far you overbore the 390. If you took it to 4.130", you could use any 428 pistons you wanted to, to obtain the desired compression. The one thing you have to remember is that the 428 crank is externally balanced. You need to keep the 428 balancer and flywheel together with the 428 crank, and have them balanced together.

Hope this helps.

Take care,
-Chris

03-15-2002, 11:36 AM	#1
Mach1 Cobra Jet Registered Member Join Date: Mar 2002 Location: Berkeley Springs, West Virginia Posts: 13	Need Some Engine Help I have a few questions for some of you FORD Mustang guru's. I have a 69 Mach 1 that I am restoring. I have a 390 Motor and want to put a 428 Crank in it and 428 heads. Will this work and do you know of what other modifications I may need to make to make this work. The motor is from a donor pickup. I don't know what to expect from the stock heads. Also I think the headers would fit fine and all I would have to do is switch motor mounts and get a drop down bracket for the power steering. The car was originally a 351W which is long gone. I am also looking for a top loader 4 speed for the 390 if you know of anything. Any help greatly appreciated. Thanks, David __________________ David 69 Mach1, 351 Cobra Jet, FMX Automatic, 15 X 7 Frt and 15 X 8 Rear Magnum 500's With Firestone Firehawk SS20 Tires. Hooker Headers, Flowmasters, Red With Black Interior. 9" Rear with 3:50 Positrac Gears. Also 70 440-6V Cuda, 4 Speed (Not A Ford, But Very Sweet) 2001 Dodge 2500 4X4 Ram 24 Valve Cummins Diesel, (Black Beauty). 1998 Dodge 4X4 Durango SLT.

03-15-2002, 11:49 AM	#2
mean81GT Registered Member Join Date: Nov 2001 Location: NY Posts: 299	we are doing the exact same thing with our 70 fastback. Here is the info i have. 390 block CJ 428 heads ( we are going with aluminum repro's from Summit) 428 crank, rods, pistons, rings (all in one kit from PAW) as far as the toploader, we are trying to find one too...sorry. if you have any other questions, i'll see what i can answer. __________________ I'm a glutton for punishment.

03-15-2002, 12:05 PM	#4
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	I can't help much, but I'll share what I know. Except for the CJ 428 and the SCJ 428, 428 heads are the same as 390 heads. The 390 and 428 blocks are pretty much the same (except for the bore), and the rods are the same. Swapping a 428 crank into a 390 would work with either set of rods, but would require special pistons, depending on how far you overbore the 390. If you took it to 4.130", you could use any 428 pistons you wanted to, to obtain the desired compression. The one thing you have to remember is that the 428 crank is externally balanced. You need to keep the 428 balancer and flywheel together with the 428 crank, and have them balanced together. Hope this helps. Take care, -Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

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03-15-2002, 11:53 AM	#3
thunderbolt Registered Member Join Date: Oct 1998 Location: Houston, TX, USA Posts: 380	That swap gets you to a 406. (not counting overbore) I am not sure if the pickup 390 was the same as the truck 390 (sometimes called the 391) but the latter has a slightly different size front bearing on the crank. (think this is right, front snout or something here, truck versions were larger than car versions and can be turned down to fit) If you find a 391 it can be bored to 428 specs and fitted with the crank. Not sure if you can bore it again. Are the heads for the 390 different than the 428? I don't remember, seems to me like they were the same. I know you are not supposed to swap big valve versions onto 352's. As you can tell I am no expert on FE engines but hope this gives you some help. That book "Ford High Proformance" has a large section on FE engines.