I was just curious if you can use the 3.4l crank and connecting rods and put them into the 2.8l standard block?

 

not witout boring it out i beleive.

but you can throw in a 3.1 crank with your pistons i believe

 

3.1 crank and 3.4 crank are the same. the only diff between the 3.1 and 3.4 is the bore. your 2.8 pistons (if those are what you are planning to use) might have a different wrist pin location. i'm not 100% sure though.

 

Yea all your doing is turning it into a 3.1L.
Get some 3.1L pistons and you will be good to go.
You can tell people you stroked your 2.8 (to a stock 3.1L ).
You will have to make sure you have the right 2.8L block, 87 and up I think it is.

 

All there is to it is you will be changing your stroke. you will need different pistons.
The rods are the same in all 2.8/3.1/3.4 engines, they all have different pistons and the 3.1 and 3.4 share the same crank shaft.
Think of the 3.4 as a bored 3.1 (don't try to bore the 2.8's or 3.1's 3.50'' bore to the 3.4's 3.62'' bore, the 3.4 is it's own block casting).

 

Perhaps explain the value of obtaining a 3.4 crank and rods from a 3.4 engine, to install into a 2.8 block.
Meaning
what is preventing you from also taking the whole 3.4 engine?
Especially considering the 3.4 block is unique and a 2.8/3.1 block (not enough metal for boring to size) cannot be made into a 3.4 engine.
A complete used running 3.4 engine can be had for as little as $210 (the lowest price obtained so far).
Why waste any effort for machining costs of a project like you are thinking? Least not forget the parts (pistons, etc) needed.
Go find the right answer (a complete 3.4) for a low cost & enjoy your car. There are thousands of those engines available.

 

www.car-part.com

 

Lol I didnt say I wanted to put a 3.4l crank and rods into my 2.8l, was just curious about compadability. Whats preventing me from doing 3.4l swap is lack of knowing people that could do it for me and not knowing how to do it myself and lack space and tools to do such a job.

 

Plus I'd bet it'd have to be an 87-89 2.8 block, since '87 was the first set of 2.8 crankshafts to have the extra counterweight. All 3.1's and 3.4's got that counterweight, so I doubt a 3.1/3.4 crank would fit into an 81-86 2.8 block.

But I think AM91_Camaro's right, I think the 3.1's pistons' wrist pins were closer to the top of the piston b/c of the extra "throw".

The rods are really the same on all 60 degree v6's?? I didn't know that!

 

Read my 2.8->3.4 Long Bock Swap Boogie Thread and figure it out!
IT is attainable for most, even yourself!
Give the thread a reading.

 

These guys sell short and long block 2.8 that have been stroked / bored to 3.4L So apprantley it can be done. If you read the notes there is some modifications that need to be done to the block it self in order to make it reliable.

My question is how far could you take the 2.8/3.1 block or even the 3.4 with a custom crank? Not that there would be any cost bennifit over droping a larger engine in, but just curious. How much stroke could these blocks take?

Edit, Dam forgot the link. here it is

http://www.engine-parts.com/GMV6/gm2834stkr.html