Hello all. I got a 72 FE 390 bored .060 over. its making some noise in the mid/bottom end and is due for rebuild. I would like to put some better parts in it, but not quite the best. Modist budget build. What would all ya'll suggest for this, mainly daily driver, some towing, and off-roading.

 

Check the bore. See if you can get away with honing it again, or if it needs to be overbored again. If it does need to be overbored again, you'd be at .080" over, and it would be best to have it sonic checked to make sure it will handle the bore. Sonic checking should be relatively cheap, as I recently paid $30 to have a V6 block checked. Also be aware that your piston options change when you go .080" over. Summit doesn't even sell .080" over 390 pistons! You may have to consider a new block if yours cant stay at .060" over.

Anyway, as to parts:

KB / Silvolite number KB150 pistons
Crane 343901 camshaft
4 barrel intake, 600cfm carburetor (I prefer Holley myself)
Home clean-up / port the heads
Headers

Should run good.

 

If the walls are thick enough to go .080 over, and you need to, that would be 4.13, 428-piston size. =)

 

This is true. Ford even made this motor combination, being 4.13" bore and 3.784" stroke. They called it the 406, and it was the predecessor to the 427.

However, I challenge you to find pistons that work in this combination! I'm not saying they aren't out there, but I at least haven't been able to find them.

Now, if he got a 428 crank he would be good to go at 4.130" as then he could use one of the multitude of 428 pistons available. Really, he would then have a 428!

 

I know it will take the rotating assembly for a 427 as I have one.

 

Well yeah... 390's and 427's have the same stroke!

 

Whats the difference in a 390 and 427 crank?

 

Some 427 cranks are forged. Some of the forged ones had grooved main journals, and some were cross-drilled. There was also a Nascar crank with wider rod journals.

 

Well I think thats a big step for most 390 blocks,,going out to a 4.130" bore..remember you need to keep a min of at least .100" thickness on the thrust side walls...Or you'll run into overheating problems...and Possible cylinder failure..

If it Might help anyone..I'll post the sonic check in my gallery of my CJ block..

JMO..

RJ

 

My 390/427 has about 1500 hard Miles on It in about 5 years. Don't use it often. but when I do. It makes the 100 miles to town generally empty and return loaded. Last load had 2 ton on truck and 1000 gal septic tank with all heavy wall 4 inch pipe for leach field on trailer. Plus what ever else we couldn't get on truck. This on mostly old logging roads posted at 25 MPH. Only remember going to 3rd a couple of times on the passes. Top speed on gearing is about 55 MPH. 3rd around 30. The harder she pulls the better she runs. Must be a good build as she held up well and loved the work out.
I was told that it was line board to take a heavy 427 crank and had steal billet main caps with the rear having 4 bolts. If it would ever quit snowing I will bring her to the shop to overhaul the Holly. As the gaskets have dried out and she was losing gas at bowl and sucking air. I plan to drop the pan and do some miking. Kept braking cams (two) during break in. Didn't know to drop one valve spring then to break in big cams. I put a little better than an RV cam in It when I got it and have had no trouble. Got a cube van now and don't have to tie load in. Just stack it in and roll the door down. Now if i was to put that box on the ford and sell the Chebby. All would be well in my fleet. But it is a 24 foot box and the 66 only has a 12 foot bed. Don't really want to lengthen frame but have been there and done that on a lot heavier trucks so know how. Would like a wrecker body or shop truck utility body for her if anybodies got one?
Would like to add that the block, heads and intake were shipped to a speed shop in Seattle. They Checked the block (Said it was good to 427) did the boring and decking as well as porting. They also balanced the rotating assembly. Still trying to find what shop did the work so I can get a copy of the build sheet. PO hasn't found his yet.

 

Interesting...

"line bored to take a 427 crank"

This should not have been necessary. 390 cranks and 427 cranks share the same main journal dimension at 2.7488". Maybe they were not straight or something, but no line boring should be necessary. A 427 crank should drop into any FE block.

That must be one weird block to have 4 bolts on the rear main bearing. Normally IIRC the 427's were cross-bolted on the 3 middle mains.

I'd start a thread on this. Something fishy is going on here...

Oh and Russ, that's why I told him to have it sonic checked! That way he will know for sure what his block will do. Takes the guesswork out of it.

 

thanks for the info guys. not sure what will happen yet, still have to get my car on the road. so lets hope it holds until then.