3.8 pistons in a 350

so is this a direct fit or is there a mjor difference between the two?

 

direct fit other than the v6 pin height is lower making the compression height VERY low. Call Postons Buick, they have stock replacement or flat top hypers with valve reliefs for 350 in stock.

 

Depends on your build... If you're sticking NA, then go with postons direct replacements.

If you're doing a Twin Turbo build, then I'd think Turbo V6 pistons would probably be better.

That's what I'm going with when I do the TT build for my 350. But I plan on going all the way and running alot of psi... so low compression won't really be an issue:Brow:

Of course.. if actual forged turbo 350 pistons are available when I do it, that'll be my ideal choice.

 

will higher compression v6 pistons help?

 

the 3.8L is a shorter deck block than the 350 / 340 as it's based on the 300. the pin height is shorter to help the piston get down to that lower deck height.

it would be easy to make it work if you were going to put new custom rods in it.

 

quick question is there any longer rods availible to put the piston where it needs to be?

 

i would think you'd have to have them made custom but you'll need to work out the rod length needed for the compression depth you want.

IIRC, some of the SBB guys in the smaller displacements have been turning the crank down a little and adapting Chevy rods. i don't know how this would work for you. offset grind the crank a little and you could also stroke the 350 just a teensy bit.

 

JE pistons list a 3.82 piston w/ 29 cc dish, 1.85 Comp. Ht. Set of 6 for $537. If your pistons are in the hole at least .040, these would work.

 

If someone wants forged pistons and rods then you need to get either both custom pistons and rods or only custom pistons if you go the sbc rod direction.

Eagle makes a forged rod ($500) that is 6.3 and has a 2.00 big end, it just needs to be narrowed a bit and then a custom piston of course. All together about 1300 fro the sbc rods modified and the custom pistons so still cheeper than what I am using (1295 for Herche rods and 800 for Diamond pistons). I am VERY pleased with my herche rods though do not get me wrong but custom parts cost big money, the diamond pistons are EXCELLENT as well!

 

In one 350 we had we used V6 flat top pistons and stock 350 rods and that combo worked out good .

 

i did some caunculations and i think itd come to 8.55 compression ration even making up for the difference in crank throw,is this right to anyone else?

 

If you are talking about the motor I just referred to the compression ratio was 11.7 , that was figured through very careful calculations .

 

Why do you want to put 3.8 pistons in a 350? I have a set of stock Federal Mogul/Forged Power .030 pistons I need to get rid of for cheap

 

im looking to put in forged pistons in and im lookin to keep the cost down. i think i can do it for cheaper buying 3.8 turbo forged pistons than i can with 350 pistons. that and i might do some turbo/supercharging later.

 

you should buy the pistons fron the above post, he wants around $250 and that will be cheeper than any other option. I used the same pistons on my 398 hp 8.3:1 engine. The forged v6 pistons will leave you very low on compression. To the tune of 7.5:1 if using the turboo pistons and the regular v6 pistons leave you at around 7.9 which is not so bad but no forged pistons available in the regualr v6 spec. The 3.0 v6 option is ok if going for a naturally aspirated build for racing that will be closer to 11.7:1 due to the full flatt top on te piston.

 

For me 11.7 made a nice street motor , not my good one though . But then it all depends on the heads . I have seen 8.5 pistons produce 12.6 with the right head combo .

 

well if i come up with $250 before he sells ill give him a ring.

 

As far as Im concerned- you need them, I have them. So I have no problem holding them for you until your ready for them. But if you decide to go another route let me know so I can offer them to someone else.