transamws6_97

iTrader: (5)

After hanging with the guys for the past few days gets me thinkin about my car again and maybe I should start planning to save some stuff for a rebuild since I do have 166k+ So I have a few questions. Since the trans am will most likely be my dd for a long time the rebuild wont be crazy. Right now I'm getting 20+ mpg on this tired old motor and I'd like to keep it that way. My thinking would be freshen up the bottom end to a 355 and do a cam and maybe port stock heads. So my questions are

1. What kinda cam would be good for streetable power (midrange) and keep decent drivability and good gas mileage.

2. With respect to roller rockers...does it make much of a difference going from 3/8 stud to 7/16 and for a street motor is it really beneficial to go non self aligning.

3. Would porting the heads do much for fuel economy...good or bad?

4. What would be a good compression ratio? I'll be running premium gas.

RamAir95TA

iTrader: (2)

1.) Read the cam sticky at the top of the page. For what you're looking for I would recommend the Crane 227 or one of AI's emissions-friendly custom grinds.

2.) A 7/16" stud is far more rigid than their 3/8" counterparts. Non self-aligning rockers are far more stable at higher RPMs than self-aligning.

3.) The point in porting heads is to increase runner volume and velocity in an attempt to put more air/fuel mixture into the combustion chambers, increasing fuel consumption. A big part of fuel economy also has to do with the tune.

4.) Static compression ratio has nothing to do with whether or not you can run pump gas. There are guys (like myself) running closer to 13:1 running on pump gas without a problem. It is far more dependent on the cam choice and your overall dynamic compression ratio.

SexyTransAm

iTrader: (6)

if it aint broke dont fix it

badass383formula96

i agree with above, mine had 195,500 miles on it and i threw h/c/i an bolt ons on it and drove it without a tune for 20k cuz i didn't care. i wanted to spray it so i threw a brand new motor in that i had just rebuilt for another car that i could spin to the moon. sold the stock 195k motor an now its in another car. If it runs good sounds good id leave it alone, there's a good amount of lt1s running around with well over 200,000 miles on them that are still DD.

transamws6_97

iTrader: (5)

well I'm not gonna pull it for nothing. I just think it'd be good to start gathering parts for when it does go. That way I'm not dropping a huge wad when it goes.

Z28 boy

My thinking was exactly the same. I just finished a 355 rebuild with Hotcam and full exhaust and a tune. It is my only car. The reason i wanted it rebuild was because it was going to be seeing 3 hour drives often because of where i go to school. There was probably nothing wrong with the motor. These things last a long damn time. I saw one in town for sale that had 250,000 miles on it.

Its all up to you..........................but it is a good excuse to make it faster.