any advantage to keeping org block?

[Bumpside Bobby]

I'm getting ready to rebuild my 390. its the org block and is bored .30 over.
might be able to rebuild it at .040 over and keep the org block. Or, just buy one of them nice LONG blocks I see on Ebay. So, the Question: any advantage to keeping and rebuilding the org block?
Bobby

[jzjames]

Yeah, “Numbers matching” I guess. That’d be a personal thing probably unless it’s a rare show truck.

[JoshT]

Well in Ford trucks "numbers matching" doesn't really exist. Ford didn't stamp a VIN number on parts in most of their vehicles back then. Best you can hope for is a date code that matches or pre-dates the vehicle by a reasonable amount. Who knows what a reasonable amount is on an engine block.

If it were mine (and I plan to do this in the future) I'd get another block to build. That way I could take my time, build it right, and keep the truck working until it's ready to install. Then, if I had space, I'd store that original block for future needs or future owners.

[cep62]

any advantage to keeping and rebuilding the org block?

Yes , you can have the machine shop you choose , carefully build your motor.
then if you have a problem you can communicate with the builder.

I'd get another block to build. That way I could take my time, build it right, and keep the truck working until it's ready to install. Then, if I had space, I'd store that original block for future needs or future owners.

This a good idea also.

[Ranchero50]

A .010" overbore won't clean up a .030" bore.

I see an original vintage / year engine being valuable if you are trying to represent it as "original". Otherwise as long as you don't get too fer out of whack you'll be OK. With FE's you don't have a lot of choices. Find a good .030" short block and install some nice aftermarket heads, cam and induction package that'll play well together. Install and enjoy.

[tnlprt]

Numbers matching means nothing in the f100 world

Find any post 65 4.05 bore block and start over
Or bore yours to .060 over and have fun with it
Mine is .060 over and performs flawlessly
Mine also has more aftermarket pieces than most

Location will help find a block
I have 20 just south of St Louis

[jzjames]

So there’s no real differences in say, the casting, of the various F100 blocks?

[JoshT]

As far as I am aware, for F-100 FE blocks there no real difference from the stand point of a factory style engine rebuild.

In the greater family of FE engine blocks there were top oiler (standard) and side oilers, there were the standard 2 bolt main and crossbolt mains. Side oilers and crossbolt mains are rare to find and I don't think they ever came in the trucks. Some block castings are better for big bores and extreme high power production, Google has a lot of info on that stuff if you want to look for it. Once again it isn't really going to matter for a standard rebuild.

[tnlprt]

Lots of differences in the FE blocks used in the F series trucks
2 bolt motor mounts ...Pre 1965
4 bolt motor mounts ...Post 1964
2 finger main web.....Pre 1973
3 finger main web ....Post 1972
4.00 inch bore .........Pre 1968
4.05 inch bore...Pre and Post 1967
FE block ...Dist bottom hole
FT block...Needs a bushing in dist hole for FE dist

There is NO difference between a car block and the pickup block

Some prefer the 1973 and up mirror 105 blocks because it has the 3 finger main web

Be careful when using google when searching out facts on the FE engine family .
There is more bad info published than good info

[Ranchero50]

Weren't some thicker inside? Not like it means much to a basic rebuild.

[Bumpside Bobby]

WOW, lots of good advice. I think I will keep my block and have it rebuilt at a local shop.
I found some .040 over pistons online, but need to have the block checked before I buy them.
It has .030 over now and had real good compression before tear down. Thanks for all the input.
Bobby