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Discussion Starter · #1 ·
I saw a link to an article that said what all they came in and also how much are pistons for a 4.1 also I know this is a dumb question but is a 4.1 better than a 3.8

Thanks
Brent
 

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Someone Crown My Ass!
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Not really. You can get forged J&E pistons for about $500-$600 a set or run hypers like I have for about $150 a set. I will post some more info when I get home.
 

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Some important things to note about the 4.1 production block:

-Open lifter valley style on the 4.1 unlike the 3.8 which is reinforced and more of a closed style. Never heard of one cracking there but nod goes to the 3.8.
-The deck of the 4.1 is .125" thinner from jump than the 3.8 deck. Potential for deck cracking is greater and less meat to deck. Nod to the 3.8.
-The 4.1 bolt hole threads in the deck to secure the heads come to the surface draws from that area where the 3.8's deck threads are deeper in the cylinder and do not come to the surface. Nod to the 3.8.
-The bottom ends are virtually identical in all areas. Even.
-The 4.1 is siamese bore which could create a cooling problem although I never heard of it.


The 4.1 will make more power but could give up the ghost quicker too. That being said I have both and will run the 4.1 hard when it gets put in the car. I think you can get most all the makeable power out of the 4.1 with hyper pistons and if it should give up the ghost you aren't loosing a bunch of cash. MHO
 

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The price of pistons has been the biggest deterent to running a 4.1 V6.
From Summit one can buy the proper Federal pistons and rings for the 4.1 motor. They are less then $200 (for both pistons and rings!) and they are in stock. Yes they are Hypers and yes that is cheap. Scottie has gone 10.30's so far (3.8 Hypers) and I have gone 11.15 with the 4.1 version. Until I prove myself wrong I will keep building 4.1's and I will be using the hyper pistons... headbang
 

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Next week I will be taking my T down for a few runs (first time in over 1 1/2 years) dunno :D and feel I will get a 10 something. I am going to run it on alcohol and limit the boost to 23 PSI or so. Pretty much full weight TR with Hyper pistons. I guess I will be the test mule to see how they hold up in the 10's. loser
 

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First post. Staying on the 4.1 theme.

Here is the project. We have a 4.1 to build. It will be a carb (Q-Jet) turbo from an '83 3.8. We have exhaust manifolds from '85 turbo and will fabracate the up pipe to the turbo.

The plan is to bore .030 and purchase hyper pistons and rebuild kit, up the intake valve size and do some home port work.

We will most likely use some type of water/alky injection, probably after the turbo.

Any suggestions on cam selection and compression ratio.

Any other suggestions.
 

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The FM hypers will keep the compression around 8:1. As for the cam I personally will use a stock GN cam in my next 4.1 build. If you wanted to buy new, keep it simple and get something as close to stock as possible... Those are my thoughts.. powersix
 

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frank:
Here is the project. We have a 4.1 to build. It will be a carb (Q-Jet) turbo from an '83 3.8. We have exhaust manifolds from '85 turbo and will fabracate the up pipe to the turbo.
Cool. :cool:

The 83 Turbo V6 used the same exhaust manifolds as a 84/85. No need to fabricated the up-pipe. Just get one from a 78/83 RWD (non-Riviera) Turbo V6.

I need to find a 4.1 yup
 

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So what is the likelihood of getting into the 12s with a turbo carbed 4.1 in a 2nd generation Firebird?

Also, actually are exhaust manifords must be '86 turbo, that why we need to fabracate the up pipe. Thank for the info though.
 
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