Does anyone have a good source to order a short block from? I just looked over my local bone yard today and there was plenty of older 2.8L RWDs but no 3.4s. I may be better off just going with a short block for now and building it up.

 

www.car-part.com

 

It shouldn't cost more than 800 bucks to have a 2.8 rebuilt and bored to a 3.1, plus you'd have a new motor....

 

2.8s and 3.1s have the same bore. the difference is in the stroke length.

 

I hope I didn't loose any face by saying that..... but he could still bore it and get close with out having to getting another crank. I think it would be about 3.05L?

 

the way i see it is a 3.1 over a 2.8 is a 10% gain, and to to a 3.4 is another 10% (from 2.8). if you say no to the 10%, thats half of the gain you arent going to get. you could buy a 3.4 shortblock for an extra $100, rebuild that and get double the gain(bore & crank are only differences). and if you bore the 3.4 block, theres even more gain.

 

Naft is right on track with what I'm thinking. That and the earlier 2.8s like have were notorious leakers. I want to start with an engine GM got most the bugs out of rather than dealing with the older mill's problems. As of right now I'm thinking of going with the 3.4 block and heads, 2.8L carb intake and maybe a Weber carb or a TBI intake off of an S10 with a 2.8. Thanx for your input. You guys have been great.

How much of an overbore will these blocks accept?

 

if you get it sonic tested the upper limit is .070 i think, but that would be with a perfect block, and you wouldnt have any rebuilds left to it.

id say .030 is a safe bore, go .040 if you want, but anything higher than that and you would probably have to get custom pistons, and would be pushing it without getting the block tested. although people pretty much give away broken 660 engines, so maybe worrying about keeping the same block is pointless.

 

I did .060 on mine and repeatedly take it to 6500 without a worry. The pistons were on the shelf at the rebuild shop. No custom orders. Plus, if I have to get a new block at 150k, who cares. It will take me another 10 years to put that many miles on the car! But it would probably be more reliable to only go as far as .040 like he said. The 3.4 is a bore .120" larger than the 3.1 right?

 

its 3mm, so whatever that converts to . . . . .3/2.54 = yah .120

the aluminum 2.8 can be overbored 2mm, but thats still only .080 overall there ends up being around .2l that you can never get without starting from a 3.4 block

 

You guys are awsome. Does anyone on the west coast know where I can get a 3.4 motor complete? I'm back and forth between using and not using the Fuel injection. I think I should do it!

 

heh, im in the market for a 3.4 too, so if i find 2 ill be sure to let you know.

 

Mine needs to be RWD as well.