Discuss some engine set ups? Need ideas

[LEWETHETIGER73]

So I need some automotive idea help here. Car has no motor or trans right now. So I am open to ideas. My main goal is to build a slightly fuel efficient car. Preferable 15- 20mpg. It is a 73 Pontiac Lemans 2dr. I was looking at either a 350 with an over drive trans with highway gears in back, LS motor and overdrive trans. What are some pros and cons to either set up. And any ideas what is all needed to do an ls conversion.

[Ricky Bobby]

go with the LS and trans u will have to do research on what all u will need for ur car

[Prince Valiant]

At 15-20mpg, it's hard to make something NOT get that...

I always recommend the most cost effective way, and really it'd be this:

Basic 350 short-block ~ 8.5:1 compression (so you can run regular).
Cam specing b/w 190-200 @ 0.050 lift, like the two smallest summit cams...the second smallest would prob be best.
Basic 3 angle valve job, or if you want to splurge, get some 350 eddy AL heads (closed chamber, bump compression ratio to 9.5:1)
Basic eddy or offy intake
Get a good distributer with vacuum advance
an eddy 500 and have someone who really knows how to tune the idle and part throttle circuits go through it good.
tri-y or cheap summit headers and 2, 2 1/4, or 2 1/2 inch duals

Pair that with 2.71-3.08 gears, and you'd have a VERY efficient car.

I ran a coronet that had 2.76:1 gears, 318 with a summit 204 @ .050 cam, eddy 600, headers and good distributer and got b/w 19.5-22 mpg coming back from maine where I bought the car...at speeds ranging from 70-80mph.

My valiant was running low 14's with an OD manual trans and 2.94 gears (made the effective final drive ratio 2.20:1), 9:1 360, mp 228 @ .050 cam (.455 lift) headers and good distributer and I could get 24-26mpg with discipline going 55-60mph.

It's pretty easy to get the numbers you're looking for...

[BR3W CITY]

No shock coming from me, but LS all the way.
You didn't mention what kind of power you wanted to make for the "slightly fuel efficient" setup. I'll assume you want something with enough power to smoothly get her around, and have some fun...but not a monster. I'd say grab a 5.3 and 4l60 combo (car-part.com, I know Rhine auto in plymouth sells pullouts). Mild cam and springs/rods with that engine will get you well over a mild 350ci power levels, smooth with o/d and you should see 20+ on the freeway. I'm not sure how heavy that thing is, but I don't see why 16-19 city wouldn't be possible with a decent rear gear. You could probably go a bit more radical on the engine and still get there with a reasonable right foot.

As for doing it to your car; Transdapt and about 10 others sell swap mounts; that is for sbc-to LS conversion. I dont know shit about BOP setups, but if the mount style is the same it shouldn't be a problem. They can move the engine forward or back depending on which one, so look at the overall dimensions to see how you need to adjust. If you want to keep the fuel injection, then you need to get the ecm as well, and have a harness made or adapt one yourself. If you like carbs' you can just swap the manifold and run a carb setup (there is still wiring of course) but they can still be economical and make great power. Carb or efi the ls would meet your power and efficiency goals.