68FirebirdAP

iTrader: (3)

I am restoring a 68 firebird and will be buying a donor car(LS1/LS2&T-56) in probably 6-8 months. I am not sure if i should spend the extra money to go for an LS2 or get an LS1 and modify it.

I would like to make 400-450hp and get 25+ mpg highway (i will be doing a lot of highway driving). I have never messed with engines newer than the late 70s before, so i am not sure how easy it is to work on/upgrade these engines.

Any recommendations are appreciated

bczee

iTrader: (12)

Go LS2.. it will be easier to reach the 400-450hp mark... key in on researching and getting recommendation on the Cam if you expect to get good MPG as a DD or Highway cruiser.

But a LS1 can get your there with the right parts (H/C/I) and a good tune. Might cost less to start with, but will pay more to get where you want.

BC

91FormulaKiller

iTrader: (28)

have you thought about LS truck engines?? Far cheaper and accept all the same mods with the same results. My 67 Firebird is getting a stock 4.8L with a single turbo and will push out over 600hp for half the cost of an LS2 drop out... just my .02. Good Luck

Tommy69z

iTrader: (4)

or go LS3/L92/L99, currently getting ready for an L92 into my 69 camaro...500rwhp is easy as a cam swap

superdave84

Actually my LS2 dropout only cost me $3200, although admittedly most of them are more.

Super Chevy did an article back in 2008 on the common upgrades for the LS1 and LS2. One of the reasons I chose an LS2 (after my 5.3 plan fell apart) is that the LS2 is so incredibly responsive to upgrades. In the article, just bolting on a set of long tube headers to an LS2 took it from 405hp to 462hp.

Now of course, results will vary. You'll need a tune to eliminated the VATS, emissions, etc, at which point you can also add a performance tune. I was told mine would be roughly 30 extra hp. Plus a few for a CAI....and we're talking some real numbers.

I don't expect all those numbers to add up on top of each other and be like 490hp, however 450, 460 is easily achievable with an LS2...and that's before a cam upgrade or a 'charger.

Here is the article: http://www.superchevy.com/technical/...s/viewall.html

HCI2000SS

iTrader: (2)

Your cheapest option would probably be a 6.0 LQ4 or LQ9

Pop N Wood

iTrader: (1)

Carb'd LS2 motors are rated at 440 HP right out of the crate. I have one in my 240z and with a stock cam and 750 DP get 25 mpg highway. It would probably go up a couple of mpg if I had a 6 vs 5 speed trans. Turning a few too many RPM at 70 mph.

LS2's have quite a few improvements over the LS1.

http://www.gmhightechperformance.com..._look_feature/

Also the 4 inch bore allows you to upgrade to LS3 heads

nofun

I'm going with a 5.3 in my 68. For the money you can't beat it.
But I'm not looking for 450hps, just a nice highway car.