hannes_slanec

Hello guys, I built 78 Trans Am with a LT1 with the matching 6-speed tranny.
Before the ECM gets a new program I would need which low budget modifications I can make to the LT1 since later I dont want to send the ECM again for re-programing.
I cannot spend much as it is frame off restoration but thinks like

Cam
Air Filter
Air Intake System
Porting of the heads and Throttle Body

and stuff like that I can do.

What I have already is

94 LT1
the 6-speed which belongs to the engine
long tube header (I guess hooker)
2,5 mandrel belt dual exhaust with X-pipe
Dynomax SS freeflow-mufflers (I think that is right name)
Usual 2,73:1 limited slip rear end
15 x 8,5 torque thrust II
BF-Goodrich Radial T/A 265/50/15


Ok now I wait for your opinion what are the best things.
If you recommend parts like a cam for example please
specify exactly which on and which datas the cam should have. It will be a fun car but the economy is also a point as
the liter gasoline costs 1,50$ in Austria.

Thanks and best regards

Hannes

Captainofiron

iTrader: (1)

well first what kind of power are you looking at making? Also since you mentioned the price of gasoline I assume you want it to get good fuel economy. If you arent looking to spend lots of money I suggest just putting the stock engine in and spending the rest on the body and interior, but if you dont mind waiting on it to look perfect, then get the performance goodies.

Also I dont know how much it would cost to get the heads and intake shipped over here, but there are a few guys that lots of people seem to use and be really happy with their work, e.g. Lloyd Elliot.

As far as the filter my suggestion would just be an open element cone filter mounted after the MAF, that would flow nicely and be cheap. Anyways really cool project hope everything goes well

rob97ss

iTrader: (1)

How many miles are on the motor?I would freshen it up before i do a cam or head work.Also get aleast 3.42 gears.Good luck.Ohh and stay away from the Pontiac boards,they'll torture you for putting a chebby in that Trans Am..LOL

Jditlfm

iTrader: (26)

Those 2.73's are going to kill you with a 6 speed i would get 4.10's. It will make the car more drivable

Captainofiron

iTrader: (1)

Can you imagine the shipping cost of a Pontiac 400 overseas, GOD. lol

yea I was tempted to throw the line out there: first mod buy a Pontiac 400, haha

but yea thats good advice for the 3.42s, sixth gear is really really tall, I would have to say to tall for the 2.73s

hannes_slanec

It is crazy, before half an hour a friend was here and told me also the 2,73 will be too short
I would like to buy a 12 bolt posi for this project but first I dont know if it gives one for this car and if so, the price would be crazy.
I wrote that certain 10 bolts are very durable and stable but I dont know which one are that, I think the 8,5 but how will I find out which one my Firebird has???
I think 4,10:1 is a bit too short, I want that the engine turns not to high on the highway.

Thansk for the answers so far, keep posting

Hannes

Captainofiron

iTrader: (1)

I dont know for sure, but I think the 78 Trans Am has the 8.5 10 bolt rear axle.

hannes_slanec

I found this 10 bolt posi carriers. The first two I dont know. I think the second one is one of this limited slip carriers (is not a real posi right?)

The last one looks like my 12 bolt Impala Posi but it is 7,5 10 bolt.
Would that be the right one if I find it for 8,5 rear ends?
I would like a real posi as I plan to accelerate with power by 3-4000 rpm (6-speed).

http://cgi.ebay.com/ebaymotors/GM-7-...QQcmdZViewItem

http://cgi.ebay.com/ebaymotors/1978-...QQcmdZViewItem

http://cgi.ebay.com/ebaymotors/Chevy...QQcmdZViewItem

Any hint?

camar0corey

iTrader: (22)

4.10s are ok with the 6 speed, at 70-75 I'm only turning 2000-2200 rpms.

hannes_slanec

Sounds interesting, the first gear will be really short, right?
I hope I am fast enough to click the first 3 gears!
For that short first gear I would need a real posi.
I have heard that all he 70-81 Trans Am/ Firebird/ Camaros have this limited slip diffs but I dont know if it is ok for my use.

Hannes

camar0corey

iTrader: (22)

Yeah first gear goes to like 25mph or something.

If you want to spend less get the slp short throw shifter and their is a stick on ebay I'm running, I'll PM you the link. Its the cheapest shifter setup I think you can find and there is basically no way you can miss 3rd, the thing just about makes you quicker.

Ah seems you don't have a private message option??
Also seems the guy doesn't sell it as a combo anymore, but still I think the SLP shifter is like $99 most places, and then the stick is less than $20.

Captainofiron

iTrader: (1)

honestly you should be ok with a limited slip, the posi is good, but the limited slip will do better in normal driving conditions and in turns than a posi unit would. Plus limited slips are easier to find

hannes_slanec

I have to look, I think the 70-81 F-Bodies had a limited slip anyway.
You think if I declutch at 3-4000rpm the limited slip will do the job fine?

Hannes

speed_demon24

iTrader: (6)

[QUOTE=camar0corey]Yeah first gear goes to like 25mph or something.
QUOTE]

You must have 6.30's in it or something like that to only be able to do 25 in 1st.

hannes_slanec

Sorry Speed Damon, I did not understand what you mean.
The first gear will not go higher than 25mph with 4,10:1?
What about the 6,30 you stated?

Thanks Hannes

camar0corey

iTrader: (22)

Your not the only guy confused now, I shift around 5400 rpm, when I had the stock 3.42 the car would hit around 35mph, now with the 4.10s it gets to around 25mph. I guess I should order tunercats and fix my speedometer to see what it really does in 1st, but typically I'm about 10mph high on my speedometer.

Jditlfm

iTrader: (26)

42 MPH with 4.10's and 5800 rpm and then 50 MPH with 3.42's at 5800 RPM.
38 MPH With 4.10's at 5400 RPM and then 45 MPH with 3.42's at 5400 RPM

http://www.f-body.org/gears/

Helps alot

hannes_slanec

My friend made a calclation and said also the 4.10 sounds very good.
What is your opinion, will the 265 BF Goodrich radial T/A tires only slip in the first or will I have at least a bit traction?
I think about to convert to a pro street 4-link as I have a good offer. If any body is interested I can post the link to it.
It is actually a ver short (short in the length between of the wheels, just a drag race rear end) from a 70´Camaro with wilwood brakes and, 12bolt
girdle and the 4-link. I would take the girdle for my Impala 12 bolt as well as the wilwood brakes, the 4-link I could use on the Firebird and the rest I would resell (is hard to get here in Austria and will sell).


Hannes

LT1MAN

iTrader: (6)

you need bigger tires. if you are going to run 15" wheels you need to have 15"x3.5"s up front and 15"x15"s in the back with mickey thompsons.

hannes_slanec

It is actually the car I built for my Girl and the whole project costs already 10 000€ (including frame off media blasting, T-Top conversion etc, etc...)
She bought the complete set of 4 Torque Thrust original with Tires and if I tell her now that she need other wheels she kills me and I think if I give widther rear tires next time (285 should also fit) it will work.

Hannes