I miss my factory 3.1. It had plenty of power and at 70 on the freeway got 36 mpg.. But alas, it blew the bottom end at 135,000 miles.. So, I had someone replace it with a Chev crate rebuilt 3.1 but was never happy with it.. At 190,000 miles I noticed that the cam was flat on at least 3 lobes with one barely opening the valves.. Replaced the cam, lifters, timing gear and chain but have just never been happy with this engine. Right now it fluctuates between 20 and 25mpg, lacks power, vac is 18 to 19 at idle but steady, and uses a little oil. It's now at about 260,000 (so 130,000 on the crate motor) and since this is my daily driver, I want to build up a replacement engine and do a swap in a few months. I am pretty much a stock guy when it comes to my Camaro's since I consider them collectors. Thinking I would pick up a rebuilder from a bone yard. Looking for thoughts, comments, etc. about how it goes to rebuild one of these and any thing to look out for during the process. How far can the block be bored out and crank turned, where to get a good stock cam and lifters, etc. etc. etc...

Thanks...

 

skip the 3.1
go pick up a good condition 3.4, take the block over to a machine shop for a slight over bore just enough to clean up the cyls. and get new pistons and rings.
delta 260 or 252 grind cam.
self port the heads, and have the machine shop do a 3 angle valve job and cut the heads for a slight bump in compression.

reuse the stock 3.1 intake but gasket match it.

 

So, what does that do for gas mileage?

What doaner car and year for a 3.4L?

What's the effect of a 260 versus 252 cam?

Does the computer need to change?

Distributor or timing changes?

Drop in replacement for motor mounts and manual trans bell housing?

Thanks.

 

2.8/3.1/3.4 are all exteranly identical except the 3.4 intake
93-95
260 cam makes more midrange and upper rpm hp and tq
252 makes more low to low mid range power

u can reuse ur stock ecm but getting a new chip to tune for the ported heads and cam will make it run alot better allowing u to get the most out of the setup
with any mods liek cam and or ported heads u should get a new tune anyways to get the most out of them even if it is the original engine

3.4 has a dis ignition system , but once u swap ur 3.1 intake on u will be using ur stock distributor

yup direct bolt in with the exception of the oil pan, intake and front timing cover .
u really only need to change the intake , but if u dont change the oil pan and timing cover there is a slight chance ur factory y-pipe may not fit as the 3.4 oil pan is slightly deeper then the 2.8/3.1

u can just use the stuff of ur current engine though