FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: fastback 427 on August 21, 2015, 04:28:47 PM
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My buddy is looking to rebuild his recently deceased 390 in his f250. Doing this on a limited budg(newer wife,new baby, new house). Truck is a 76 f250, 4spd, 4.10, spd, 37" tires. Use is some towing, winter driving.
He is looking at staying with the stock crank and rods, as a 445 isn't in the budget. Looking at a line hone, bore with torque plate, polish the crank (hopefully). He has a,750 carb, new performer rpm, new set of heddman Elite headers. Wondering what would be a good rebuid kit and cam. Last time it had to much compression, about 10.7,
and pinged horribly. Maybe some hypereutectic or forged pistons. Wondering if you guys had some thoughts on how you would build it. Thanks.
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How is he at 10.7:1?
That would take a domed piston in a 390 with common +/-72cc heads...
More info please.....
I sell pretty normal basic kits as do others. They include a flat tappet stick - but any of us would need more data before selecting the "right" piston and cam package.
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He has the pistons out but cannot find a number yet. They are flat tops with 4 valve reliefs. He was told they are car 4bbl 10.5 to one. Heads are c7ae-a and have been more milled a little. He will c.c. the chamber this weekend. He sent me a pic of the damaged thrust bearing and cam bearings. The cam bearings look like they are melting out around the cam. Trying to post it but having trouble.
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In a truck like that, I'd likely go 270H, between 9.5 and 9.75:1 compression, tight quench (.005-.010 below), then spend the money on a real good valve/port job and distributor recurve.
The more money in the heads, the more power it will make on the entire curve. I also think at the RPM he'll be at, I'd run stock hydraulic rockers and just make sure valve stem and pushrod lengths are perfect. Keep in mind, he is likely stuck with the low port exhaust with the truck headers
Hypers or forged pistons will work fine, just needs to pick based on hitting numbers above (if he chooses that route)
The key is good blueprinting, don't guess at any of the numbers or just guess at all of them :)