Engine Mods

mark20 · Feb 15, 2010

What is the difference between Super M pistons or 400 pistons? Can I run both pistons in my M block with no sleaves? What is the difference between a M cam or a Super M / 400 cam? I take it that the valves in a Super M head/400 head must be bigger than a M head? Is there one better than the other?

Andrew Z · Feb 15, 2010

The Super M and 400 are almost the same engine
they are both the c-264. if you want to improve
upon the Super M you need to look for C-281 (450)
engine. The overbore for the Super M/400 is a 4
1/8" piston this is the stock bore for the 450.
These sleeves will fit right in the Super M
without boring. As for the head deck it, if you
want more then look for a 450 gas or better
450/400 lp head. But i would not spend the money
for one.

Andrew

mark20 · Feb 16, 2010

the cams are the same I take it ?

Anonymous-0 · Feb 16, 2010

New reproduction 450 cams are available, right around $190.00

450 cam had a better grind for performance.

Chad

mark20 · Feb 16, 2010

a 450 cam will fit in a '43 m block ? Any problems with running a 450 cam, 450pistons with a #8060 head decked. Everything will bolt in? Just trying to cover all my bases before I start buying and building.

Andrew Z · Feb 16, 2010

The 450 Cam will fit right in, the 450 pistons will
not fit in the M block without boring. The largest
you can go without boring in the M block is a 4"
piston. the Super M/400 engine will except the 4
1/8" without boring.

Andrew

mark20 · Feb 17, 2010

Would i be better off to bore the m block out just for the 450 pistons, bore it out to except 450 sleaves or just run the super m pistons.Much power diff?

Anonymous-0 · Feb 17, 2010

450 pistons, in the M block with no sleeves, no boring.

Counter bore rings made from the M sleeve.

Or deck the block to eliminate the counter bore flange in the block entirely. No counterbore rings needed.

ChadS

mark20 · Feb 17, 2010

Looking at the engine kits , a overbore kit for a super m is also 4 1/8 piston , but the 450 piston is the better way to go ? better performance? My engine ser# is 62358. By the way it looks , there are 2 differant piston pin size , 1 inch and 1 5/16. The 450 piston I think is a 1 inch pin , any guess on what mine is. thanks for all the help !!

Anonymous-0 · Feb 18, 2010

You will have the big pins. Order for a Super M, the pistons will go onto your M rods.

450 set might be lighter, but the wrist pin bushing used in the late 400, were pretty heavy too.

I have some used pistons for sale. 4.125 bore, very high compression. ChadS

Engine Mods

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