[78 gp]

My +.030 400 has forged TRW L2262f30 pistons and I was wondering if anyone has ever heard of installing pistons 180deg. (backwards) from the recommended position? i.e. arrow marked front facing to the rear. I heard that doing so would increase performance, something about the wristpin centerline being moved, at the risk of longterm durability( increased piston rock or something about piston thrust against the block).

[78 gp]

My +.030 400 has forged TRW L2262f30 pistons and I was wondering if anyone has ever heard of installing pistons 180deg. (backwards) from the recommended position? i.e. arrow marked front facing to the rear. I heard that doing so would increase performance, something about the wristpin centerline being moved, at the risk of longterm durability( increased piston rock or something about piston thrust against the block).

[78 gp]

Hello,
I am a new member to the site, but I've lurked since the day's of the old board. I take it from the lack of response's that no one has heard of installing them backwards. How about just thought's on the idea. A local pontiac guru once mentioned it and I wonder how valid the idea is? I posted on the race board since, although a basic question, I think that the more expierenced people might have some ideas about the subject. I am not saying that expeirence = speed or any other deductions some might make. At any rate any input would be appreciated. thanks
78 gp

[T Hutchinson]

This was an old trick use on BBC. I just recently read (I think on this board somewhere) a discussion about rod/stroke ratio, in it this modification was briefly mentioned and discarded as not reccomended. Sorry I cant give more info but I think any performance gains would be marginal, and at the expense of longevity. Otherwise the piston manufactures themselves probably would have employed this "trick" long ago.

Todd

[Guy Mazza]

I have heard of this trick.....I've never done it, nor do I know anyone who has. I try to keep my Pontiac motors simple. Those engineers at Pontiac had it goin on! My ole 455 went 11.79 @112.00 in a 3700lb 69 GTO w/ STOCK 16 heads,STOCK RA IV cam, cast rods, and STOCK TRW replacement pistons installed in the stock manner! Good Luck, Guy O.P.R.A.

[Old Man Taylor]

I do not recall the details, but I do remember reading one article of someone who did this on a Pontiac. Their conclusion was that it did not provide measureable benefit. It is my understanding that the stock Pontiac configuration has the wrist pin offset slightly to reduce piston noise. Pop-up pistons are centered as they can only be installed one way.

------------------
Jim

[Big Injun]

The trick you are speaking of is an old trick used to increase your piston dwell.

Big Mopars came from the factory this way.

------------------
Dave "Big Injun" Anderson
www.PontiacDragDays.com
www.PontiacEnthusiast.com

[T Hutchinson]

Jeez Guy... 11.79? I've run that exact combo with high 12's and thought I was doin good. Can you tell your secret? Or would you have to kill me?

Todd

[PROBRD]

Hey, that is impressive Guy. I've run almost the same combo only difference is a 400 block for high 12's. Where did you hide the bottle? LOL.

------------------
PROBRD
([email protected])

[PONTIAC DUDE]

Yes, this is an old trick, but you have to remember, back then your choice of parts was 1/3th that of today so no big deal now. Any little help was needed then for records in NHRA. Stock class was ALOT different back then. Same as putting in a longer rod (moving the pin outwards) but harder on the sideload of the piston. But who cared back then. Later. http://Pontiacpower.cc

[Guy Mazza]

No real trick guy's. I must have read Jim Hand's article way back when "street fighting ponchos" (HPP) This combo ran the 11.79 @ Pontiac Enthusiast magazines "Tribal Challenge" in Carlsbad,Cal. (sea level, good air...bad traction). Anyway, old combo also had 10in TCI conv, 4.10 gears w/spool, 29.5 x 10.5 M/T slicks. Out of the box (unjetted) 750 DP carb. 6 point bar. Shifted 1-2 4800 & 2-3 4800-5000! Ran this combo UNTOUCHED for 4 years....NO BOTTLE. Kept it real simple.
Long May Lou run!, Guy O.P.R.A. www.geocities.com/racedagto/der_judge_.jpg

[This message has been edited by Guy Mazza (edited 07-04-2000).]

[78 gp]

Thanks for the info,
I will sleep better now. The engine was assembled that way several years ago and since the engine is currently out right now, I thought I would ask about the practice and depending on the response leave it as is(backwards), or change it around. So far it looks as if it will be staying as is. At any rate I will be posting a new thread (titled "400 sugestions") with my combination and hope to have suggestions I can take advantage while the engine is out. By the way, it's a Crane RAIV cammed 400 w/16 cast# d-port heads.
Thanks again,
78 GP

[78 gp]

Forgot to mention that the new post will be in the Race forum since the compresion ratio is not all that streetable.
Later,
78 GP