Fordnatics List Archive

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Mail From: (email redacted) ( Steve Sadler )

I've talked in the past about my 351W stroker plans, and gotten a few
great answers.

Finally I've begun the quest: I bought a machined block and a 400M crank.

MY QUESTIONS:

A)
The crank does not fit in the block. How much of the outside diameter do I
need to grind off the crank?


The rod journal on the 400M crank measures 1.780".

I miced the three rods I had laying around:

351W: .835
351C: .837
289: .834

None of these are going to work (if I stack two side by side, and shoot for
.025 clearance, I'm still (1.780-(2*.835)-.025) .085 too wide.

I can use 351W rods if I add material (and then machine down) to the sides
of the rod journals.

I another option is to use Chrysler Small block rods and Keith Black pistons
(KB189), but I have to offset grind the crank to 4.075", bush the small end
of the Chrysler rods to .927", thin the rods to .880", and spend $40.00 each
piston. This combination yields 415.8" @ a 4.030" bore.

Of the two, I like the Chrysler rod idea better, because of the longer stroke
and the longer rod. I really would like to have forged pistons instead of
hypereutectic.

Can anybody else give me some ideas? I've got to decide which way to go
before I go any farther.

Any help anybody can give me would really be appreciated. If you'd like to
call and give me some advice, my phone number is (916)399-1789. Or, if you
leave me email with your number I'll call you back.

Thanks,
Steve Sadler

(Hopefully, soon to be the happy owner of a 6.8L small block)

This read-only message was archived from a public mail list.
Mail From: (email redacted) (Dave Williams)


-> The crank does not fit in the block. How much of the outside
-> diameter do I need to grind off the crank?

On the order of 1-1/2". The counterweights aren't round, they're sort
of football shaped. I recommend cutting it down to almost to the rod
journals. That will help with piston clearance (bottom of piston to
crank cheeks) later.

Your crank shop can do the counterweights in about two hours using the
crank grinder, but it'd be a lot better to find a place with a lathe
big enough to cut it with a lathe. It'd save a lot of money.


-> The rod journal on the 400M crank measures 1.780".

Sounds like it was either made too wide to start with, or reground too
wide. Not much you can do about the side clearance.


-> Of the two, I like the Chrysler rod idea better, because of the
-> longer stroke and the longer rod. I really would like to have forged
-> pistons instead of hypereutectic.

The Chrysler rod is probably stronger than the Ford one. I wouldn't
worry much about forged vs. hypereutectic. If you go Chrysler, you can
offset to 1/8" and use a common Chevrolet 1.3-ish piston. Or you could
offset the crank to 4.13 and use the 6.205" Ford 300-6 rods and KB112
pistons with the 1.21 pin height.


-> Can anybody else give me some ideas? I've got to decide which way to
-> go before I go any farther.

You'll need to notch the block at the oil pump boss to clear the front
counterweight. There's a ring around the front of the crank, ahead of
the front main. It has to be machined off so the lower timing sprocket
can move back in line with the upper. The keyway needs to be extended.

Personally, I'd use the 351W rods and 302 pistons. It'd all match up
without any extra machining and save you a sizeable chunk of money.
Longer rods are better, but that'd be a very expensive eighth of an
inch.