My machine shop has a pontiac performance freind that tells him, if he puts the pistons in backwards(to where the notch points to the back of the engine) tye 60 400 engine will make more power. Anyone heard of this? Thanks

My machine shop has a pontiac performance freind that tells him, if he puts the pistons in backwards(to where the notch points to the back of the engine) tye 60 400 engine will make more power. Anyone heard of this? Thanks

Somebody's smokin' dope! http://forums.performanceyears.com/g.../icon_razz.gif

I've heard of guys doin this in small block chebs to get rid of side loading on the piston and free up a few ponies.It moves the pin in closer to the cam and for all practical puposes does its job but decreases the longevity of the engine due to increased loading of the crank at the main caps.And we all know about loading Ponts in the mains causes cracked webs http://forums.performanceyears.com/g...s/icon_eek.gif and such.I do not recomend it for street car.Maybe in a properly preped race only block but if you have the money for that then have a set of properly designed pistons made to move the pin http://forums.performanceyears.com/g.../icon_wink.gif.

http://community.webshots.com/user/stripleduce

I don't think it works.

The real reasons why the pin is offset are:

A.) Quieter running engine (less piston slap noise on cold start up).
B.) Easier on the rod bearings (a "glancing" blow on the bearing the the spark plug goes off is easier on the bearing than a "straight on" blow).

Most racing pistons have the pin location centered. I can't imagine why anyone would want to run an OEM piston backwards in any application nowadays.

http://kurtspontiac.homestead.com/files/bbaker.jpg

It is an old hot rodders' trick. It works...just look at the stock Hemi piston offsets. By moving the offset you geometrically create more dwell at TDC making the engine work like it has a long rod.

It does increase side loading on the cylinder wall at BDC and not recommended for a street car.

Dave "Big Injun" Anderson
www.pontiacdragdays.com
www.geetotiger.com
http://www.pontiacdragdays.com/BigInjunPlate.jpg

The negative long term effects outweigh the small amount of added performance you may gain. There are many other upgrades you can do that would be much better for the engine than this.

This is an old Joe Sherman trick, and it does work at the expense of additional engine noise and perhaps decreased engine life.

I think some of the "stockers" do it. Shave off the arrow and restamp the piston top.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Skip Fix:
I think some of the "stockers" do it. Shave off the arrow and restamp the piston top.<HR></BLOCKQUOTE>

I think NHRA rules allow for the stocker to have the pin relocated to the center of the piston. They also allow for an overbore (but not much). They're not using OEM cast pistons in Stock or Super Stock.

http://kurtspontiac.homestead.com/files/bbaker.jpg

As Big Dave said.

It works.

Not for daily use.
As it was a racing trick that "Everyone" knew. http://forums.performanceyears.com/g.../icon_wink.gif

Build it fast, build it right, build a Pontiac.

http://PontiacDude.cc

Brian, some of the guys still use TRWs and they are on the NHRA approved replacement list. Venolia, and some others have some. I know John Schloe was still using factory RAIVs in his motor when I talked to him a few years ago. I think the pin offset has to stay the same in stock, most guys use a Dykes top ring though.

Super Stock pistons are wide open though.