???Aluminum Block???

[Nightingale]

I was looking at the original Indy beretta engine specs and I seen that it used an aluminum block . So the question is if I ever have to rebuild my 3.1L MPFI engine in my Indy would it be possible to use this aluminum block(if I can order one), and still use the orignal crank,heads and plenum. Reason being is the aluminum block for one is alot lighter and also the fact that it seems you can bore it to 92mm and get 3.4L displacement. Thanks for looking, and sry in advance if this was covered( I looked through the old posts and didn't see anything so).

Edit- Here is the block part number "10051141 Bow Tie Aluminum Block"

[Doubt_Incarnate]

yeah its a direct replacement

[Froggx]

According to the info listed on gmpartsdirect.com it can only be bored to 91mm safely and can only use an 81.28 mm stroke. 3.4 is 92 mm bore and 84 mm stroke. It is rough bored to 89mm. Sounds like it is very much designed to use 2.8L engine gear. I've heard the block can be clearanced to use the 84mm stroke crankshaft but I wouldn't quote myself on that.

[geoffinbc]

The Indy Beretta was a 3.4L was it not?

[Froggx]

The Indy Beretta was a 3.4L was it not?

I wouldn't know, I'm just quoting the information from that one site. www.gmpartsdirect.com , stick "10051141" in the part number search window and it will tell you the same thing. They could be lying, of course

[bszopi]

It had a custom crank to get it to the 3.4L. And yes it could be easily used if you have around $2k (usually) to spend on just the block.

EDIT: I was incorrect. It didn't have a custom crank

[Nightingale]

Yes the original Indy was 3.4L and I forgot it used a custom crank(as well as a few other custom parts). As for it only being able to be bored out to 91mm safely I just assumbed that 92mm would be the absolute most you could go considering it was done with the original indy block. Maybe I'll shot GM an email and ask them about clearencing for the crankshaft. Worst case scenerario would be to go with a new crank from a 2.8 I suppose.

[Doubt_Incarnate]

i though tsomeone on here had a bowtie with a 3.1 crank in it and said there wasnt any issues, but its been a while.

[eliteweapons]

bowtie block

I have the bowtie block and it'll cost ya $4000 from gm. I am still looking for a forged crank, and camshaft for it. All the other bases are covered. The block is a universal fit (so they say) and you may have to mod a few a/c brackets and definitely the oil pan. I am swapping mine out with my 95 3100 and there are a lot of mods that need to be done to make it work. Timing cover bolt holes are too small, oil pan differences due to the 4 bolt mains and as I said some brackets. This is an in progress deal due to crank and cam issues. Finding what I need.

[geoffinbc]

With that bowtie block you may have to use an older style stamped pan.

[eliteweapons]

I am going to try a pan from the grand prix turbo and see if it works withthe factory oil return stub

[Nightingale]

Hmmm well its some food for thought for sure. I think this will definitely be a backburner type project for me. Main concern is rewiring the car(short) and leak proofing it(something leaked and flooded the interior out). Something else came up is what about pistons and connecting rods? Would you have to go with custom forged jobs(aluminum pistons with fordged steel rods?).

[Froggx]

IMO if you have that much money to spend on the block I wouldn't worry about the costs of pistons/rods. Get custom pistons for under a grand easily then use SBC con rods.

[eliteweapons]

Yes I have a custom set of rods from crower and a custom set of forged pistons from arias. I am going to be punching 20 psi down this thing at max of 7500 rpm so I want it to hold together.

[Doubt_Incarnate]

personaly, i see no point whatsoever in the bowtie except for the whole 50lbs or so (not really a swell idea to remove weight from over the drive wheels is it?) and bragging. it stops at the 3.4l mark(if it gets there) and since all the new blocks have the sbc type oiling as well the much anticipated 3.9L displacment. i'd rater wait a few years and find a 3900vvt and thought the block is heavier, it has the makings of the big block of the 60* family. much larger 99mm bore with the biggest valves, since the ls1 shares the same bore, whos to say that you cant wriggle some monster 2.02" and 1.72" valves in. i think that motor will make the first 12 second all motor J.

even tho the bowtie bolts up pretty much, i find the much greater displacment a more appealing option. you can build up a sweet 3400 and make it fit and work for the price of just the bowtie.